1 //===--- TokenAnnotator.cpp - Format C++ code -----------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 ///
9 /// \file
10 /// This file implements a token annotator, i.e. creates
11 /// \c AnnotatedTokens out of \c FormatTokens with required extra information.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #include "TokenAnnotator.h"
16 #include "FormatToken.h"
17 #include "clang/Basic/SourceManager.h"
18 #include "clang/Basic/TokenKinds.h"
19 #include "llvm/ADT/SmallPtrSet.h"
20 #include "llvm/Support/Debug.h"
21 
22 #define DEBUG_TYPE "format-token-annotator"
23 
24 namespace clang {
25 namespace format {
26 
27 namespace {
28 
29 /// Returns \c true if the line starts with a token that can start a statement
30 /// with an initializer.
31 static bool startsWithInitStatement(const AnnotatedLine &Line) {
32   return Line.startsWith(tok::kw_for) || Line.startsWith(tok::kw_if) ||
33          Line.startsWith(tok::kw_switch);
34 }
35 
36 /// Returns \c true if the token can be used as an identifier in
37 /// an Objective-C \c \@selector, \c false otherwise.
38 ///
39 /// Because getFormattingLangOpts() always lexes source code as
40 /// Objective-C++, C++ keywords like \c new and \c delete are
41 /// lexed as tok::kw_*, not tok::identifier, even for Objective-C.
42 ///
43 /// For Objective-C and Objective-C++, both identifiers and keywords
44 /// are valid inside @selector(...) (or a macro which
45 /// invokes @selector(...)). So, we allow treat any identifier or
46 /// keyword as a potential Objective-C selector component.
47 static bool canBeObjCSelectorComponent(const FormatToken &Tok) {
48   return Tok.Tok.getIdentifierInfo() != nullptr;
49 }
50 
51 /// With `Left` being '(', check if we're at either `[...](` or
52 /// `[...]<...>(`, where the [ opens a lambda capture list.
53 static bool isLambdaParameterList(const FormatToken *Left) {
54   // Skip <...> if present.
55   if (Left->Previous && Left->Previous->is(tok::greater) &&
56       Left->Previous->MatchingParen &&
57       Left->Previous->MatchingParen->is(TT_TemplateOpener))
58     Left = Left->Previous->MatchingParen;
59 
60   // Check for `[...]`.
61   return Left->Previous && Left->Previous->is(tok::r_square) &&
62          Left->Previous->MatchingParen &&
63          Left->Previous->MatchingParen->is(TT_LambdaLSquare);
64 }
65 
66 /// Returns \c true if the token is followed by a boolean condition, \c false
67 /// otherwise.
68 static bool isKeywordWithCondition(const FormatToken &Tok) {
69   return Tok.isOneOf(tok::kw_if, tok::kw_for, tok::kw_while, tok::kw_switch,
70                      tok::kw_constexpr, tok::kw_catch);
71 }
72 
73 /// A parser that gathers additional information about tokens.
74 ///
75 /// The \c TokenAnnotator tries to match parenthesis and square brakets and
76 /// store a parenthesis levels. It also tries to resolve matching "<" and ">"
77 /// into template parameter lists.
78 class AnnotatingParser {
79 public:
80   AnnotatingParser(const FormatStyle &Style, AnnotatedLine &Line,
81                    const AdditionalKeywords &Keywords)
82       : Style(Style), Line(Line), CurrentToken(Line.First), AutoFound(false),
83         Keywords(Keywords) {
84     Contexts.push_back(Context(tok::unknown, 1, /*IsExpression=*/false));
85     resetTokenMetadata();
86   }
87 
88 private:
89   bool parseAngle() {
90     if (!CurrentToken || !CurrentToken->Previous)
91       return false;
92     if (NonTemplateLess.count(CurrentToken->Previous))
93       return false;
94 
95     const FormatToken &Previous = *CurrentToken->Previous; // The '<'.
96     if (Previous.Previous) {
97       if (Previous.Previous->Tok.isLiteral())
98         return false;
99       if (Previous.Previous->is(tok::r_paren) && Contexts.size() > 1 &&
100           (!Previous.Previous->MatchingParen ||
101            !Previous.Previous->MatchingParen->is(TT_OverloadedOperatorLParen)))
102         return false;
103     }
104 
105     FormatToken *Left = CurrentToken->Previous;
106     Left->ParentBracket = Contexts.back().ContextKind;
107     ScopedContextCreator ContextCreator(*this, tok::less, 12);
108 
109     // If this angle is in the context of an expression, we need to be more
110     // hesitant to detect it as opening template parameters.
111     bool InExprContext = Contexts.back().IsExpression;
112 
113     Contexts.back().IsExpression = false;
114     // If there's a template keyword before the opening angle bracket, this is a
115     // template parameter, not an argument.
116     if (Left->Previous && Left->Previous->isNot(tok::kw_template))
117       Contexts.back().ContextType = Context::TemplateArgument;
118 
119     if (Style.Language == FormatStyle::LK_Java &&
120         CurrentToken->is(tok::question))
121       next();
122 
123     while (CurrentToken) {
124       if (CurrentToken->is(tok::greater)) {
125         // Try to do a better job at looking for ">>" within the condition of
126         // a statement. Conservatively insert spaces between consecutive ">"
127         // tokens to prevent splitting right bitshift operators and potentially
128         // altering program semantics. This check is overly conservative and
129         // will prevent spaces from being inserted in select nested template
130         // parameter cases, but should not alter program semantics.
131         if (CurrentToken->Next && CurrentToken->Next->is(tok::greater) &&
132             Left->ParentBracket != tok::less &&
133             (isKeywordWithCondition(*Line.First) ||
134              CurrentToken->getStartOfNonWhitespace() ==
135                  CurrentToken->Next->getStartOfNonWhitespace().getLocWithOffset(
136                      -1)))
137           return false;
138         Left->MatchingParen = CurrentToken;
139         CurrentToken->MatchingParen = Left;
140         // In TT_Proto, we must distignuish between:
141         //   map<key, value>
142         //   msg < item: data >
143         //   msg: < item: data >
144         // In TT_TextProto, map<key, value> does not occur.
145         if (Style.Language == FormatStyle::LK_TextProto ||
146             (Style.Language == FormatStyle::LK_Proto && Left->Previous &&
147              Left->Previous->isOneOf(TT_SelectorName, TT_DictLiteral)))
148           CurrentToken->setType(TT_DictLiteral);
149         else
150           CurrentToken->setType(TT_TemplateCloser);
151         next();
152         return true;
153       }
154       if (CurrentToken->is(tok::question) &&
155           Style.Language == FormatStyle::LK_Java) {
156         next();
157         continue;
158       }
159       if (CurrentToken->isOneOf(tok::r_paren, tok::r_square, tok::r_brace) ||
160           (CurrentToken->isOneOf(tok::colon, tok::question) && InExprContext &&
161            !Style.isCSharp() && Style.Language != FormatStyle::LK_Proto &&
162            Style.Language != FormatStyle::LK_TextProto))
163         return false;
164       // If a && or || is found and interpreted as a binary operator, this set
165       // of angles is likely part of something like "a < b && c > d". If the
166       // angles are inside an expression, the ||/&& might also be a binary
167       // operator that was misinterpreted because we are parsing template
168       // parameters.
169       // FIXME: This is getting out of hand, write a decent parser.
170       if (CurrentToken->Previous->isOneOf(tok::pipepipe, tok::ampamp) &&
171           CurrentToken->Previous->is(TT_BinaryOperator) &&
172           Contexts[Contexts.size() - 2].IsExpression &&
173           !Line.startsWith(tok::kw_template))
174         return false;
175       updateParameterCount(Left, CurrentToken);
176       if (Style.Language == FormatStyle::LK_Proto) {
177         if (FormatToken *Previous = CurrentToken->getPreviousNonComment()) {
178           if (CurrentToken->is(tok::colon) ||
179               (CurrentToken->isOneOf(tok::l_brace, tok::less) &&
180                Previous->isNot(tok::colon)))
181             Previous->setType(TT_SelectorName);
182         }
183       }
184       if (!consumeToken())
185         return false;
186     }
187     return false;
188   }
189 
190   bool parseUntouchableParens() {
191     while (CurrentToken) {
192       CurrentToken->Finalized = true;
193       switch (CurrentToken->Tok.getKind()) {
194       case tok::l_paren:
195         next();
196         if (!parseUntouchableParens())
197           return false;
198         continue;
199       case tok::r_paren:
200         next();
201         return true;
202       default:
203         // no-op
204         break;
205       }
206       next();
207     }
208     return false;
209   }
210 
211   bool parseParens(bool LookForDecls = false) {
212     if (!CurrentToken)
213       return false;
214     assert(CurrentToken->Previous && "Unknown previous token");
215     FormatToken &OpeningParen = *CurrentToken->Previous;
216     assert(OpeningParen.is(tok::l_paren));
217     FormatToken *PrevNonComment = OpeningParen.getPreviousNonComment();
218     OpeningParen.ParentBracket = Contexts.back().ContextKind;
219     ScopedContextCreator ContextCreator(*this, tok::l_paren, 1);
220 
221     // FIXME: This is a bit of a hack. Do better.
222     Contexts.back().ColonIsForRangeExpr =
223         Contexts.size() == 2 && Contexts[0].ColonIsForRangeExpr;
224 
225     if (OpeningParen.Previous &&
226         OpeningParen.Previous->is(TT_UntouchableMacroFunc)) {
227       OpeningParen.Finalized = true;
228       return parseUntouchableParens();
229     }
230 
231     bool StartsObjCMethodExpr = false;
232     if (FormatToken *MaybeSel = OpeningParen.Previous) {
233       // @selector( starts a selector.
234       if (MaybeSel->isObjCAtKeyword(tok::objc_selector) && MaybeSel->Previous &&
235           MaybeSel->Previous->is(tok::at))
236         StartsObjCMethodExpr = true;
237     }
238 
239     if (OpeningParen.is(TT_OverloadedOperatorLParen)) {
240       // Find the previous kw_operator token.
241       FormatToken *Prev = &OpeningParen;
242       while (!Prev->is(tok::kw_operator)) {
243         Prev = Prev->Previous;
244         assert(Prev && "Expect a kw_operator prior to the OperatorLParen!");
245       }
246 
247       // If faced with "a.operator*(argument)" or "a->operator*(argument)",
248       // i.e. the operator is called as a member function,
249       // then the argument must be an expression.
250       bool OperatorCalledAsMemberFunction =
251           Prev->Previous && Prev->Previous->isOneOf(tok::period, tok::arrow);
252       Contexts.back().IsExpression = OperatorCalledAsMemberFunction;
253     } else if (Style.isJavaScript() &&
254                (Line.startsWith(Keywords.kw_type, tok::identifier) ||
255                 Line.startsWith(tok::kw_export, Keywords.kw_type,
256                                 tok::identifier))) {
257       // type X = (...);
258       // export type X = (...);
259       Contexts.back().IsExpression = false;
260     } else if (OpeningParen.Previous &&
261                (OpeningParen.Previous->isOneOf(tok::kw_static_assert,
262                                                tok::kw_while, tok::l_paren,
263                                                tok::comma, TT_BinaryOperator) ||
264                 OpeningParen.Previous->isIf())) {
265       // static_assert, if and while usually contain expressions.
266       Contexts.back().IsExpression = true;
267     } else if (Style.isJavaScript() && OpeningParen.Previous &&
268                (OpeningParen.Previous->is(Keywords.kw_function) ||
269                 (OpeningParen.Previous->endsSequence(tok::identifier,
270                                                      Keywords.kw_function)))) {
271       // function(...) or function f(...)
272       Contexts.back().IsExpression = false;
273     } else if (Style.isJavaScript() && OpeningParen.Previous &&
274                OpeningParen.Previous->is(TT_JsTypeColon)) {
275       // let x: (SomeType);
276       Contexts.back().IsExpression = false;
277     } else if (isLambdaParameterList(&OpeningParen)) {
278       // This is a parameter list of a lambda expression.
279       Contexts.back().IsExpression = false;
280     } else if (Line.InPPDirective &&
281                (!OpeningParen.Previous ||
282                 !OpeningParen.Previous->is(tok::identifier))) {
283       Contexts.back().IsExpression = true;
284     } else if (Contexts[Contexts.size() - 2].CaretFound) {
285       // This is the parameter list of an ObjC block.
286       Contexts.back().IsExpression = false;
287     } else if (OpeningParen.Previous &&
288                OpeningParen.Previous->is(TT_ForEachMacro)) {
289       // The first argument to a foreach macro is a declaration.
290       Contexts.back().ContextType = Context::ForEachMacro;
291       Contexts.back().IsExpression = false;
292     } else if (OpeningParen.Previous && OpeningParen.Previous->MatchingParen &&
293                OpeningParen.Previous->MatchingParen->is(TT_ObjCBlockLParen)) {
294       Contexts.back().IsExpression = false;
295     } else if (!Line.MustBeDeclaration && !Line.InPPDirective) {
296       bool IsForOrCatch =
297           OpeningParen.Previous &&
298           OpeningParen.Previous->isOneOf(tok::kw_for, tok::kw_catch);
299       Contexts.back().IsExpression = !IsForOrCatch;
300     }
301 
302     // Infer the role of the l_paren based on the previous token if we haven't
303     // detected one one yet.
304     if (PrevNonComment && OpeningParen.is(TT_Unknown)) {
305       if (PrevNonComment->is(tok::kw___attribute)) {
306         OpeningParen.setType(TT_AttributeParen);
307       } else if (PrevNonComment->isOneOf(TT_TypenameMacro, tok::kw_decltype,
308                                          tok::kw_typeof, tok::kw__Atomic,
309                                          tok::kw___underlying_type)) {
310         OpeningParen.setType(TT_TypeDeclarationParen);
311         // decltype() and typeof() usually contain expressions.
312         if (PrevNonComment->isOneOf(tok::kw_decltype, tok::kw_typeof))
313           Contexts.back().IsExpression = true;
314       }
315     }
316 
317     if (StartsObjCMethodExpr) {
318       Contexts.back().ColonIsObjCMethodExpr = true;
319       OpeningParen.setType(TT_ObjCMethodExpr);
320     }
321 
322     // MightBeFunctionType and ProbablyFunctionType are used for
323     // function pointer and reference types as well as Objective-C
324     // block types:
325     //
326     // void (*FunctionPointer)(void);
327     // void (&FunctionReference)(void);
328     // void (&&FunctionReference)(void);
329     // void (^ObjCBlock)(void);
330     bool MightBeFunctionType = !Contexts[Contexts.size() - 2].IsExpression;
331     bool ProbablyFunctionType =
332         CurrentToken->isOneOf(tok::star, tok::amp, tok::ampamp, tok::caret);
333     bool HasMultipleLines = false;
334     bool HasMultipleParametersOnALine = false;
335     bool MightBeObjCForRangeLoop =
336         OpeningParen.Previous && OpeningParen.Previous->is(tok::kw_for);
337     FormatToken *PossibleObjCForInToken = nullptr;
338     while (CurrentToken) {
339       // LookForDecls is set when "if (" has been seen. Check for
340       // 'identifier' '*' 'identifier' followed by not '=' -- this
341       // '*' has to be a binary operator but determineStarAmpUsage() will
342       // categorize it as an unary operator, so set the right type here.
343       if (LookForDecls && CurrentToken->Next) {
344         FormatToken *Prev = CurrentToken->getPreviousNonComment();
345         if (Prev) {
346           FormatToken *PrevPrev = Prev->getPreviousNonComment();
347           FormatToken *Next = CurrentToken->Next;
348           if (PrevPrev && PrevPrev->is(tok::identifier) &&
349               Prev->isOneOf(tok::star, tok::amp, tok::ampamp) &&
350               CurrentToken->is(tok::identifier) && Next->isNot(tok::equal)) {
351             Prev->setType(TT_BinaryOperator);
352             LookForDecls = false;
353           }
354         }
355       }
356 
357       if (CurrentToken->Previous->is(TT_PointerOrReference) &&
358           CurrentToken->Previous->Previous->isOneOf(tok::l_paren,
359                                                     tok::coloncolon))
360         ProbablyFunctionType = true;
361       if (CurrentToken->is(tok::comma))
362         MightBeFunctionType = false;
363       if (CurrentToken->Previous->is(TT_BinaryOperator))
364         Contexts.back().IsExpression = true;
365       if (CurrentToken->is(tok::r_paren)) {
366         if (OpeningParen.isNot(TT_CppCastLParen) && MightBeFunctionType &&
367             ProbablyFunctionType && CurrentToken->Next &&
368             (CurrentToken->Next->is(tok::l_paren) ||
369              (CurrentToken->Next->is(tok::l_square) && Line.MustBeDeclaration)))
370           OpeningParen.setType(OpeningParen.Next->is(tok::caret)
371                                    ? TT_ObjCBlockLParen
372                                    : TT_FunctionTypeLParen);
373         OpeningParen.MatchingParen = CurrentToken;
374         CurrentToken->MatchingParen = &OpeningParen;
375 
376         if (CurrentToken->Next && CurrentToken->Next->is(tok::l_brace) &&
377             OpeningParen.Previous && OpeningParen.Previous->is(tok::l_paren)) {
378           // Detect the case where macros are used to generate lambdas or
379           // function bodies, e.g.:
380           //   auto my_lambda = MACRO((Type *type, int i) { .. body .. });
381           for (FormatToken *Tok = &OpeningParen; Tok != CurrentToken;
382                Tok = Tok->Next)
383             if (Tok->is(TT_BinaryOperator) &&
384                 Tok->isOneOf(tok::star, tok::amp, tok::ampamp))
385               Tok->setType(TT_PointerOrReference);
386         }
387 
388         if (StartsObjCMethodExpr) {
389           CurrentToken->setType(TT_ObjCMethodExpr);
390           if (Contexts.back().FirstObjCSelectorName) {
391             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
392                 Contexts.back().LongestObjCSelectorName;
393           }
394         }
395 
396         if (OpeningParen.is(TT_AttributeParen))
397           CurrentToken->setType(TT_AttributeParen);
398         if (OpeningParen.is(TT_TypeDeclarationParen))
399           CurrentToken->setType(TT_TypeDeclarationParen);
400         if (OpeningParen.Previous &&
401             OpeningParen.Previous->is(TT_JavaAnnotation))
402           CurrentToken->setType(TT_JavaAnnotation);
403         if (OpeningParen.Previous &&
404             OpeningParen.Previous->is(TT_LeadingJavaAnnotation))
405           CurrentToken->setType(TT_LeadingJavaAnnotation);
406         if (OpeningParen.Previous &&
407             OpeningParen.Previous->is(TT_AttributeSquare))
408           CurrentToken->setType(TT_AttributeSquare);
409 
410         if (!HasMultipleLines)
411           OpeningParen.setPackingKind(PPK_Inconclusive);
412         else if (HasMultipleParametersOnALine)
413           OpeningParen.setPackingKind(PPK_BinPacked);
414         else
415           OpeningParen.setPackingKind(PPK_OnePerLine);
416 
417         next();
418         return true;
419       }
420       if (CurrentToken->isOneOf(tok::r_square, tok::r_brace))
421         return false;
422 
423       if (CurrentToken->is(tok::l_brace) && OpeningParen.is(TT_ObjCBlockLParen))
424         OpeningParen.setType(TT_Unknown);
425       if (CurrentToken->is(tok::comma) && CurrentToken->Next &&
426           !CurrentToken->Next->HasUnescapedNewline &&
427           !CurrentToken->Next->isTrailingComment())
428         HasMultipleParametersOnALine = true;
429       bool ProbablyFunctionTypeLParen =
430           (CurrentToken->is(tok::l_paren) && CurrentToken->Next &&
431            CurrentToken->Next->isOneOf(tok::star, tok::amp, tok::caret));
432       if ((CurrentToken->Previous->isOneOf(tok::kw_const, tok::kw_auto) ||
433            CurrentToken->Previous->isSimpleTypeSpecifier()) &&
434           !(CurrentToken->is(tok::l_brace) ||
435             (CurrentToken->is(tok::l_paren) && !ProbablyFunctionTypeLParen)))
436         Contexts.back().IsExpression = false;
437       if (CurrentToken->isOneOf(tok::semi, tok::colon)) {
438         MightBeObjCForRangeLoop = false;
439         if (PossibleObjCForInToken) {
440           PossibleObjCForInToken->setType(TT_Unknown);
441           PossibleObjCForInToken = nullptr;
442         }
443       }
444       if (MightBeObjCForRangeLoop && CurrentToken->is(Keywords.kw_in)) {
445         PossibleObjCForInToken = CurrentToken;
446         PossibleObjCForInToken->setType(TT_ObjCForIn);
447       }
448       // When we discover a 'new', we set CanBeExpression to 'false' in order to
449       // parse the type correctly. Reset that after a comma.
450       if (CurrentToken->is(tok::comma))
451         Contexts.back().CanBeExpression = true;
452 
453       FormatToken *Tok = CurrentToken;
454       if (!consumeToken())
455         return false;
456       updateParameterCount(&OpeningParen, Tok);
457       if (CurrentToken && CurrentToken->HasUnescapedNewline)
458         HasMultipleLines = true;
459     }
460     return false;
461   }
462 
463   bool isCSharpAttributeSpecifier(const FormatToken &Tok) {
464     if (!Style.isCSharp())
465       return false;
466 
467     // `identifier[i]` is not an attribute.
468     if (Tok.Previous && Tok.Previous->is(tok::identifier))
469       return false;
470 
471     // Chains of [] in `identifier[i][j][k]` are not attributes.
472     if (Tok.Previous && Tok.Previous->is(tok::r_square)) {
473       auto *MatchingParen = Tok.Previous->MatchingParen;
474       if (!MatchingParen || MatchingParen->is(TT_ArraySubscriptLSquare))
475         return false;
476     }
477 
478     const FormatToken *AttrTok = Tok.Next;
479     if (!AttrTok)
480       return false;
481 
482     // Just an empty declaration e.g. string [].
483     if (AttrTok->is(tok::r_square))
484       return false;
485 
486     // Move along the tokens inbetween the '[' and ']' e.g. [STAThread].
487     while (AttrTok && AttrTok->isNot(tok::r_square))
488       AttrTok = AttrTok->Next;
489 
490     if (!AttrTok)
491       return false;
492 
493     // Allow an attribute to be the only content of a file.
494     AttrTok = AttrTok->Next;
495     if (!AttrTok)
496       return true;
497 
498     // Limit this to being an access modifier that follows.
499     if (AttrTok->isOneOf(tok::kw_public, tok::kw_private, tok::kw_protected,
500                          tok::comment, tok::kw_class, tok::kw_static,
501                          tok::l_square, Keywords.kw_internal))
502       return true;
503 
504     // incase its a [XXX] retval func(....
505     if (AttrTok->Next &&
506         AttrTok->Next->startsSequence(tok::identifier, tok::l_paren))
507       return true;
508 
509     return false;
510   }
511 
512   bool isCpp11AttributeSpecifier(const FormatToken &Tok) {
513     if (!Style.isCpp() || !Tok.startsSequence(tok::l_square, tok::l_square))
514       return false;
515     // The first square bracket is part of an ObjC array literal
516     if (Tok.Previous && Tok.Previous->is(tok::at))
517       return false;
518     const FormatToken *AttrTok = Tok.Next->Next;
519     if (!AttrTok)
520       return false;
521     // C++17 '[[using ns: foo, bar(baz, blech)]]'
522     // We assume nobody will name an ObjC variable 'using'.
523     if (AttrTok->startsSequence(tok::kw_using, tok::identifier, tok::colon))
524       return true;
525     if (AttrTok->isNot(tok::identifier))
526       return false;
527     while (AttrTok && !AttrTok->startsSequence(tok::r_square, tok::r_square)) {
528       // ObjC message send. We assume nobody will use : in a C++11 attribute
529       // specifier parameter, although this is technically valid:
530       // [[foo(:)]].
531       if (AttrTok->is(tok::colon) ||
532           AttrTok->startsSequence(tok::identifier, tok::identifier) ||
533           AttrTok->startsSequence(tok::r_paren, tok::identifier))
534         return false;
535       if (AttrTok->is(tok::ellipsis))
536         return true;
537       AttrTok = AttrTok->Next;
538     }
539     return AttrTok && AttrTok->startsSequence(tok::r_square, tok::r_square);
540   }
541 
542   bool parseSquare() {
543     if (!CurrentToken)
544       return false;
545 
546     // A '[' could be an index subscript (after an identifier or after
547     // ')' or ']'), it could be the start of an Objective-C method
548     // expression, it could the start of an Objective-C array literal,
549     // or it could be a C++ attribute specifier [[foo::bar]].
550     FormatToken *Left = CurrentToken->Previous;
551     Left->ParentBracket = Contexts.back().ContextKind;
552     FormatToken *Parent = Left->getPreviousNonComment();
553 
554     // Cases where '>' is followed by '['.
555     // In C++, this can happen either in array of templates (foo<int>[10])
556     // or when array is a nested template type (unique_ptr<type1<type2>[]>).
557     bool CppArrayTemplates =
558         Style.isCpp() && Parent && Parent->is(TT_TemplateCloser) &&
559         (Contexts.back().CanBeExpression || Contexts.back().IsExpression ||
560          Contexts.back().ContextType == Context::TemplateArgument);
561 
562     bool IsCpp11AttributeSpecifier = isCpp11AttributeSpecifier(*Left) ||
563                                      Contexts.back().InCpp11AttributeSpecifier;
564 
565     // Treat C# Attributes [STAThread] much like C++ attributes [[...]].
566     bool IsCSharpAttributeSpecifier =
567         isCSharpAttributeSpecifier(*Left) ||
568         Contexts.back().InCSharpAttributeSpecifier;
569 
570     bool InsideInlineASM = Line.startsWith(tok::kw_asm);
571     bool IsCppStructuredBinding = Left->isCppStructuredBinding(Style);
572     bool StartsObjCMethodExpr =
573         !IsCppStructuredBinding && !InsideInlineASM && !CppArrayTemplates &&
574         Style.isCpp() && !IsCpp11AttributeSpecifier &&
575         !IsCSharpAttributeSpecifier && Contexts.back().CanBeExpression &&
576         Left->isNot(TT_LambdaLSquare) &&
577         !CurrentToken->isOneOf(tok::l_brace, tok::r_square) &&
578         (!Parent ||
579          Parent->isOneOf(tok::colon, tok::l_square, tok::l_paren,
580                          tok::kw_return, tok::kw_throw) ||
581          Parent->isUnaryOperator() ||
582          // FIXME(bug 36976): ObjC return types shouldn't use TT_CastRParen.
583          Parent->isOneOf(TT_ObjCForIn, TT_CastRParen) ||
584          (getBinOpPrecedence(Parent->Tok.getKind(), true, true) >
585           prec::Unknown));
586     bool ColonFound = false;
587 
588     unsigned BindingIncrease = 1;
589     if (IsCppStructuredBinding) {
590       Left->setType(TT_StructuredBindingLSquare);
591     } else if (Left->is(TT_Unknown)) {
592       if (StartsObjCMethodExpr) {
593         Left->setType(TT_ObjCMethodExpr);
594       } else if (InsideInlineASM) {
595         Left->setType(TT_InlineASMSymbolicNameLSquare);
596       } else if (IsCpp11AttributeSpecifier) {
597         Left->setType(TT_AttributeSquare);
598       } else if (Style.isJavaScript() && Parent &&
599                  Contexts.back().ContextKind == tok::l_brace &&
600                  Parent->isOneOf(tok::l_brace, tok::comma)) {
601         Left->setType(TT_JsComputedPropertyName);
602       } else if (Style.isCpp() && Contexts.back().ContextKind == tok::l_brace &&
603                  Parent && Parent->isOneOf(tok::l_brace, tok::comma)) {
604         Left->setType(TT_DesignatedInitializerLSquare);
605       } else if (IsCSharpAttributeSpecifier) {
606         Left->setType(TT_AttributeSquare);
607       } else if (CurrentToken->is(tok::r_square) && Parent &&
608                  Parent->is(TT_TemplateCloser)) {
609         Left->setType(TT_ArraySubscriptLSquare);
610       } else if (Style.Language == FormatStyle::LK_Proto ||
611                  Style.Language == FormatStyle::LK_TextProto) {
612         // Square braces in LK_Proto can either be message field attributes:
613         //
614         // optional Aaa aaa = 1 [
615         //   (aaa) = aaa
616         // ];
617         //
618         // extensions 123 [
619         //   (aaa) = aaa
620         // ];
621         //
622         // or text proto extensions (in options):
623         //
624         // option (Aaa.options) = {
625         //   [type.type/type] {
626         //     key: value
627         //   }
628         // }
629         //
630         // or repeated fields (in options):
631         //
632         // option (Aaa.options) = {
633         //   keys: [ 1, 2, 3 ]
634         // }
635         //
636         // In the first and the third case we want to spread the contents inside
637         // the square braces; in the second we want to keep them inline.
638         Left->setType(TT_ArrayInitializerLSquare);
639         if (!Left->endsSequence(tok::l_square, tok::numeric_constant,
640                                 tok::equal) &&
641             !Left->endsSequence(tok::l_square, tok::numeric_constant,
642                                 tok::identifier) &&
643             !Left->endsSequence(tok::l_square, tok::colon, TT_SelectorName)) {
644           Left->setType(TT_ProtoExtensionLSquare);
645           BindingIncrease = 10;
646         }
647       } else if (!CppArrayTemplates && Parent &&
648                  Parent->isOneOf(TT_BinaryOperator, TT_TemplateCloser, tok::at,
649                                  tok::comma, tok::l_paren, tok::l_square,
650                                  tok::question, tok::colon, tok::kw_return,
651                                  // Should only be relevant to JavaScript:
652                                  tok::kw_default)) {
653         Left->setType(TT_ArrayInitializerLSquare);
654       } else {
655         BindingIncrease = 10;
656         Left->setType(TT_ArraySubscriptLSquare);
657       }
658     }
659 
660     ScopedContextCreator ContextCreator(*this, tok::l_square, BindingIncrease);
661     Contexts.back().IsExpression = true;
662     if (Style.isJavaScript() && Parent && Parent->is(TT_JsTypeColon))
663       Contexts.back().IsExpression = false;
664 
665     Contexts.back().ColonIsObjCMethodExpr = StartsObjCMethodExpr;
666     Contexts.back().InCpp11AttributeSpecifier = IsCpp11AttributeSpecifier;
667     Contexts.back().InCSharpAttributeSpecifier = IsCSharpAttributeSpecifier;
668 
669     while (CurrentToken) {
670       if (CurrentToken->is(tok::r_square)) {
671         if (IsCpp11AttributeSpecifier)
672           CurrentToken->setType(TT_AttributeSquare);
673         if (IsCSharpAttributeSpecifier)
674           CurrentToken->setType(TT_AttributeSquare);
675         else if (((CurrentToken->Next &&
676                    CurrentToken->Next->is(tok::l_paren)) ||
677                   (CurrentToken->Previous &&
678                    CurrentToken->Previous->Previous == Left)) &&
679                  Left->is(TT_ObjCMethodExpr)) {
680           // An ObjC method call is rarely followed by an open parenthesis. It
681           // also can't be composed of just one token, unless it's a macro that
682           // will be expanded to more tokens.
683           // FIXME: Do we incorrectly label ":" with this?
684           StartsObjCMethodExpr = false;
685           Left->setType(TT_Unknown);
686         }
687         if (StartsObjCMethodExpr && CurrentToken->Previous != Left) {
688           CurrentToken->setType(TT_ObjCMethodExpr);
689           // If we haven't seen a colon yet, make sure the last identifier
690           // before the r_square is tagged as a selector name component.
691           if (!ColonFound && CurrentToken->Previous &&
692               CurrentToken->Previous->is(TT_Unknown) &&
693               canBeObjCSelectorComponent(*CurrentToken->Previous))
694             CurrentToken->Previous->setType(TT_SelectorName);
695           // determineStarAmpUsage() thinks that '*' '[' is allocating an
696           // array of pointers, but if '[' starts a selector then '*' is a
697           // binary operator.
698           if (Parent && Parent->is(TT_PointerOrReference))
699             Parent->overwriteFixedType(TT_BinaryOperator);
700         }
701         // An arrow after an ObjC method expression is not a lambda arrow.
702         if (CurrentToken->getType() == TT_ObjCMethodExpr &&
703             CurrentToken->Next && CurrentToken->Next->is(TT_LambdaArrow))
704           CurrentToken->Next->overwriteFixedType(TT_Unknown);
705         Left->MatchingParen = CurrentToken;
706         CurrentToken->MatchingParen = Left;
707         // FirstObjCSelectorName is set when a colon is found. This does
708         // not work, however, when the method has no parameters.
709         // Here, we set FirstObjCSelectorName when the end of the method call is
710         // reached, in case it was not set already.
711         if (!Contexts.back().FirstObjCSelectorName) {
712           FormatToken *Previous = CurrentToken->getPreviousNonComment();
713           if (Previous && Previous->is(TT_SelectorName)) {
714             Previous->ObjCSelectorNameParts = 1;
715             Contexts.back().FirstObjCSelectorName = Previous;
716           }
717         } else {
718           Left->ParameterCount =
719               Contexts.back().FirstObjCSelectorName->ObjCSelectorNameParts;
720         }
721         if (Contexts.back().FirstObjCSelectorName) {
722           Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
723               Contexts.back().LongestObjCSelectorName;
724           if (Left->BlockParameterCount > 1)
725             Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName = 0;
726         }
727         next();
728         return true;
729       }
730       if (CurrentToken->isOneOf(tok::r_paren, tok::r_brace))
731         return false;
732       if (CurrentToken->is(tok::colon)) {
733         if (IsCpp11AttributeSpecifier &&
734             CurrentToken->endsSequence(tok::colon, tok::identifier,
735                                        tok::kw_using)) {
736           // Remember that this is a [[using ns: foo]] C++ attribute, so we
737           // don't add a space before the colon (unlike other colons).
738           CurrentToken->setType(TT_AttributeColon);
739         } else if (Left->isOneOf(TT_ArraySubscriptLSquare,
740                                  TT_DesignatedInitializerLSquare)) {
741           Left->setType(TT_ObjCMethodExpr);
742           StartsObjCMethodExpr = true;
743           Contexts.back().ColonIsObjCMethodExpr = true;
744           if (Parent && Parent->is(tok::r_paren))
745             // FIXME(bug 36976): ObjC return types shouldn't use TT_CastRParen.
746             Parent->setType(TT_CastRParen);
747         }
748         ColonFound = true;
749       }
750       if (CurrentToken->is(tok::comma) && Left->is(TT_ObjCMethodExpr) &&
751           !ColonFound)
752         Left->setType(TT_ArrayInitializerLSquare);
753       FormatToken *Tok = CurrentToken;
754       if (!consumeToken())
755         return false;
756       updateParameterCount(Left, Tok);
757     }
758     return false;
759   }
760 
761   bool couldBeInStructArrayInitializer() const {
762     if (Contexts.size() < 2)
763       return false;
764     // We want to back up no more then 2 context levels i.e.
765     // . { { <-
766     const auto End = std::next(Contexts.rbegin(), 2);
767     auto Last = Contexts.rbegin();
768     unsigned Depth = 0;
769     for (; Last != End; ++Last)
770       if (Last->ContextKind == tok::l_brace)
771         ++Depth;
772     return Depth == 2 && Last->ContextKind != tok::l_brace;
773   }
774 
775   bool parseBrace() {
776     if (!CurrentToken)
777       return true;
778 
779     assert(CurrentToken->Previous);
780     FormatToken &OpeningBrace = *CurrentToken->Previous;
781     assert(OpeningBrace.is(tok::l_brace));
782     OpeningBrace.ParentBracket = Contexts.back().ContextKind;
783 
784     if (Contexts.back().CaretFound)
785       OpeningBrace.overwriteFixedType(TT_ObjCBlockLBrace);
786     Contexts.back().CaretFound = false;
787 
788     ScopedContextCreator ContextCreator(*this, tok::l_brace, 1);
789     Contexts.back().ColonIsDictLiteral = true;
790     if (OpeningBrace.is(BK_BracedInit))
791       Contexts.back().IsExpression = true;
792     if (Style.isJavaScript() && OpeningBrace.Previous &&
793         OpeningBrace.Previous->is(TT_JsTypeColon))
794       Contexts.back().IsExpression = false;
795 
796     unsigned CommaCount = 0;
797     while (CurrentToken) {
798       if (CurrentToken->is(tok::r_brace)) {
799         assert(OpeningBrace.Optional == CurrentToken->Optional);
800         OpeningBrace.MatchingParen = CurrentToken;
801         CurrentToken->MatchingParen = &OpeningBrace;
802         if (Style.AlignArrayOfStructures != FormatStyle::AIAS_None) {
803           if (OpeningBrace.ParentBracket == tok::l_brace &&
804               couldBeInStructArrayInitializer() && CommaCount > 0)
805             Contexts.back().ContextType = Context::StructArrayInitializer;
806         }
807         next();
808         return true;
809       }
810       if (CurrentToken->isOneOf(tok::r_paren, tok::r_square))
811         return false;
812       updateParameterCount(&OpeningBrace, CurrentToken);
813       if (CurrentToken->isOneOf(tok::colon, tok::l_brace, tok::less)) {
814         FormatToken *Previous = CurrentToken->getPreviousNonComment();
815         if (Previous->is(TT_JsTypeOptionalQuestion))
816           Previous = Previous->getPreviousNonComment();
817         if ((CurrentToken->is(tok::colon) &&
818              (!Contexts.back().ColonIsDictLiteral || !Style.isCpp())) ||
819             Style.Language == FormatStyle::LK_Proto ||
820             Style.Language == FormatStyle::LK_TextProto) {
821           OpeningBrace.setType(TT_DictLiteral);
822           if (Previous->Tok.getIdentifierInfo() ||
823               Previous->is(tok::string_literal))
824             Previous->setType(TT_SelectorName);
825         }
826         if (CurrentToken->is(tok::colon) && OpeningBrace.is(TT_Unknown))
827           OpeningBrace.setType(TT_DictLiteral);
828         else if (Style.isJavaScript())
829           OpeningBrace.overwriteFixedType(TT_DictLiteral);
830       }
831       if (CurrentToken->is(tok::comma)) {
832         if (Style.isJavaScript())
833           OpeningBrace.overwriteFixedType(TT_DictLiteral);
834         ++CommaCount;
835       }
836       if (!consumeToken())
837         return false;
838     }
839     return true;
840   }
841 
842   void updateParameterCount(FormatToken *Left, FormatToken *Current) {
843     // For ObjC methods, the number of parameters is calculated differently as
844     // method declarations have a different structure (the parameters are not
845     // inside a bracket scope).
846     if (Current->is(tok::l_brace) && Current->is(BK_Block))
847       ++Left->BlockParameterCount;
848     if (Current->is(tok::comma)) {
849       ++Left->ParameterCount;
850       if (!Left->Role)
851         Left->Role.reset(new CommaSeparatedList(Style));
852       Left->Role->CommaFound(Current);
853     } else if (Left->ParameterCount == 0 && Current->isNot(tok::comment)) {
854       Left->ParameterCount = 1;
855     }
856   }
857 
858   bool parseConditional() {
859     while (CurrentToken) {
860       if (CurrentToken->is(tok::colon)) {
861         CurrentToken->setType(TT_ConditionalExpr);
862         next();
863         return true;
864       }
865       if (!consumeToken())
866         return false;
867     }
868     return false;
869   }
870 
871   bool parseTemplateDeclaration() {
872     if (CurrentToken && CurrentToken->is(tok::less)) {
873       CurrentToken->setType(TT_TemplateOpener);
874       next();
875       if (!parseAngle())
876         return false;
877       if (CurrentToken)
878         CurrentToken->Previous->ClosesTemplateDeclaration = true;
879       return true;
880     }
881     return false;
882   }
883 
884   bool consumeToken() {
885     FormatToken *Tok = CurrentToken;
886     next();
887     switch (Tok->Tok.getKind()) {
888     case tok::plus:
889     case tok::minus:
890       if (!Tok->Previous && Line.MustBeDeclaration)
891         Tok->setType(TT_ObjCMethodSpecifier);
892       break;
893     case tok::colon:
894       if (!Tok->Previous)
895         return false;
896       // Colons from ?: are handled in parseConditional().
897       if (Style.isJavaScript()) {
898         if (Contexts.back().ColonIsForRangeExpr || // colon in for loop
899             (Contexts.size() == 1 &&               // switch/case labels
900              !Line.First->isOneOf(tok::kw_enum, tok::kw_case)) ||
901             Contexts.back().ContextKind == tok::l_paren ||  // function params
902             Contexts.back().ContextKind == tok::l_square || // array type
903             (!Contexts.back().IsExpression &&
904              Contexts.back().ContextKind == tok::l_brace) || // object type
905             (Contexts.size() == 1 &&
906              Line.MustBeDeclaration)) { // method/property declaration
907           Contexts.back().IsExpression = false;
908           Tok->setType(TT_JsTypeColon);
909           break;
910         }
911       } else if (Style.isCSharp()) {
912         if (Contexts.back().InCSharpAttributeSpecifier) {
913           Tok->setType(TT_AttributeColon);
914           break;
915         }
916         if (Contexts.back().ContextKind == tok::l_paren) {
917           Tok->setType(TT_CSharpNamedArgumentColon);
918           break;
919         }
920       }
921       if (Line.First->isOneOf(Keywords.kw_module, Keywords.kw_import) ||
922           Line.First->startsSequence(tok::kw_export, Keywords.kw_module) ||
923           Line.First->startsSequence(tok::kw_export, Keywords.kw_import)) {
924         Tok->setType(TT_ModulePartitionColon);
925       } else if (Contexts.back().ColonIsDictLiteral ||
926                  Style.Language == FormatStyle::LK_Proto ||
927                  Style.Language == FormatStyle::LK_TextProto) {
928         Tok->setType(TT_DictLiteral);
929         if (Style.Language == FormatStyle::LK_TextProto) {
930           if (FormatToken *Previous = Tok->getPreviousNonComment())
931             Previous->setType(TT_SelectorName);
932         }
933       } else if (Contexts.back().ColonIsObjCMethodExpr ||
934                  Line.startsWith(TT_ObjCMethodSpecifier)) {
935         Tok->setType(TT_ObjCMethodExpr);
936         const FormatToken *BeforePrevious = Tok->Previous->Previous;
937         // Ensure we tag all identifiers in method declarations as
938         // TT_SelectorName.
939         bool UnknownIdentifierInMethodDeclaration =
940             Line.startsWith(TT_ObjCMethodSpecifier) &&
941             Tok->Previous->is(tok::identifier) && Tok->Previous->is(TT_Unknown);
942         if (!BeforePrevious ||
943             // FIXME(bug 36976): ObjC return types shouldn't use TT_CastRParen.
944             !(BeforePrevious->is(TT_CastRParen) ||
945               (BeforePrevious->is(TT_ObjCMethodExpr) &&
946                BeforePrevious->is(tok::colon))) ||
947             BeforePrevious->is(tok::r_square) ||
948             Contexts.back().LongestObjCSelectorName == 0 ||
949             UnknownIdentifierInMethodDeclaration) {
950           Tok->Previous->setType(TT_SelectorName);
951           if (!Contexts.back().FirstObjCSelectorName)
952             Contexts.back().FirstObjCSelectorName = Tok->Previous;
953           else if (Tok->Previous->ColumnWidth >
954                    Contexts.back().LongestObjCSelectorName)
955             Contexts.back().LongestObjCSelectorName =
956                 Tok->Previous->ColumnWidth;
957           Tok->Previous->ParameterIndex =
958               Contexts.back().FirstObjCSelectorName->ObjCSelectorNameParts;
959           ++Contexts.back().FirstObjCSelectorName->ObjCSelectorNameParts;
960         }
961       } else if (Contexts.back().ColonIsForRangeExpr) {
962         Tok->setType(TT_RangeBasedForLoopColon);
963       } else if (CurrentToken && CurrentToken->is(tok::numeric_constant)) {
964         Tok->setType(TT_BitFieldColon);
965       } else if (Contexts.size() == 1 &&
966                  !Line.First->isOneOf(tok::kw_enum, tok::kw_case,
967                                       tok::kw_default)) {
968         FormatToken *Prev = Tok->getPreviousNonComment();
969         if (!Prev)
970           break;
971         if (Prev->isOneOf(tok::r_paren, tok::kw_noexcept))
972           Tok->setType(TT_CtorInitializerColon);
973         else if (Prev->is(tok::kw_try)) {
974           // Member initializer list within function try block.
975           FormatToken *PrevPrev = Prev->getPreviousNonComment();
976           if (!PrevPrev)
977             break;
978           if (PrevPrev && PrevPrev->isOneOf(tok::r_paren, tok::kw_noexcept))
979             Tok->setType(TT_CtorInitializerColon);
980         } else
981           Tok->setType(TT_InheritanceColon);
982       } else if (canBeObjCSelectorComponent(*Tok->Previous) && Tok->Next &&
983                  (Tok->Next->isOneOf(tok::r_paren, tok::comma) ||
984                   (canBeObjCSelectorComponent(*Tok->Next) && Tok->Next->Next &&
985                    Tok->Next->Next->is(tok::colon)))) {
986         // This handles a special macro in ObjC code where selectors including
987         // the colon are passed as macro arguments.
988         Tok->setType(TT_ObjCMethodExpr);
989       } else if (Contexts.back().ContextKind == tok::l_paren) {
990         Tok->setType(TT_InlineASMColon);
991       }
992       break;
993     case tok::pipe:
994     case tok::amp:
995       // | and & in declarations/type expressions represent union and
996       // intersection types, respectively.
997       if (Style.isJavaScript() && !Contexts.back().IsExpression)
998         Tok->setType(TT_JsTypeOperator);
999       break;
1000     case tok::kw_if:
1001       if (CurrentToken &&
1002           CurrentToken->isOneOf(tok::kw_constexpr, tok::identifier))
1003         next();
1004       LLVM_FALLTHROUGH;
1005     case tok::kw_while:
1006       if (CurrentToken && CurrentToken->is(tok::l_paren)) {
1007         next();
1008         if (!parseParens(/*LookForDecls=*/true))
1009           return false;
1010       }
1011       break;
1012     case tok::kw_for:
1013       if (Style.isJavaScript()) {
1014         // x.for and {for: ...}
1015         if ((Tok->Previous && Tok->Previous->is(tok::period)) ||
1016             (Tok->Next && Tok->Next->is(tok::colon)))
1017           break;
1018         // JS' for await ( ...
1019         if (CurrentToken && CurrentToken->is(Keywords.kw_await))
1020           next();
1021       }
1022       if (Style.isCpp() && CurrentToken && CurrentToken->is(tok::kw_co_await))
1023         next();
1024       Contexts.back().ColonIsForRangeExpr = true;
1025       if (!CurrentToken || CurrentToken->isNot(tok::l_paren))
1026         return false;
1027       next();
1028       if (!parseParens())
1029         return false;
1030       break;
1031     case tok::l_paren:
1032       // When faced with 'operator()()', the kw_operator handler incorrectly
1033       // marks the first l_paren as a OverloadedOperatorLParen. Here, we make
1034       // the first two parens OverloadedOperators and the second l_paren an
1035       // OverloadedOperatorLParen.
1036       if (Tok->Previous && Tok->Previous->is(tok::r_paren) &&
1037           Tok->Previous->MatchingParen &&
1038           Tok->Previous->MatchingParen->is(TT_OverloadedOperatorLParen)) {
1039         Tok->Previous->setType(TT_OverloadedOperator);
1040         Tok->Previous->MatchingParen->setType(TT_OverloadedOperator);
1041         Tok->setType(TT_OverloadedOperatorLParen);
1042       }
1043 
1044       if (!parseParens())
1045         return false;
1046       if (Line.MustBeDeclaration && Contexts.size() == 1 &&
1047           !Contexts.back().IsExpression && !Line.startsWith(TT_ObjCProperty) &&
1048           !Tok->isOneOf(TT_TypeDeclarationParen, TT_RequiresExpressionLParen) &&
1049           (!Tok->Previous || !Tok->Previous->isOneOf(tok::kw___attribute,
1050                                                      TT_LeadingJavaAnnotation)))
1051         Line.MightBeFunctionDecl = true;
1052       break;
1053     case tok::l_square:
1054       if (!parseSquare())
1055         return false;
1056       break;
1057     case tok::l_brace:
1058       if (Style.Language == FormatStyle::LK_TextProto) {
1059         FormatToken *Previous = Tok->getPreviousNonComment();
1060         if (Previous && Previous->getType() != TT_DictLiteral)
1061           Previous->setType(TT_SelectorName);
1062       }
1063       if (!parseBrace())
1064         return false;
1065       break;
1066     case tok::less:
1067       if (parseAngle()) {
1068         Tok->setType(TT_TemplateOpener);
1069         // In TT_Proto, we must distignuish between:
1070         //   map<key, value>
1071         //   msg < item: data >
1072         //   msg: < item: data >
1073         // In TT_TextProto, map<key, value> does not occur.
1074         if (Style.Language == FormatStyle::LK_TextProto ||
1075             (Style.Language == FormatStyle::LK_Proto && Tok->Previous &&
1076              Tok->Previous->isOneOf(TT_SelectorName, TT_DictLiteral))) {
1077           Tok->setType(TT_DictLiteral);
1078           FormatToken *Previous = Tok->getPreviousNonComment();
1079           if (Previous && Previous->getType() != TT_DictLiteral)
1080             Previous->setType(TT_SelectorName);
1081         }
1082       } else {
1083         Tok->setType(TT_BinaryOperator);
1084         NonTemplateLess.insert(Tok);
1085         CurrentToken = Tok;
1086         next();
1087       }
1088       break;
1089     case tok::r_paren:
1090     case tok::r_square:
1091       return false;
1092     case tok::r_brace:
1093       // Lines can start with '}'.
1094       if (Tok->Previous)
1095         return false;
1096       break;
1097     case tok::greater:
1098       if (Style.Language != FormatStyle::LK_TextProto)
1099         Tok->setType(TT_BinaryOperator);
1100       if (Tok->Previous && Tok->Previous->is(TT_TemplateCloser))
1101         Tok->SpacesRequiredBefore = 1;
1102       break;
1103     case tok::kw_operator:
1104       if (Style.Language == FormatStyle::LK_TextProto ||
1105           Style.Language == FormatStyle::LK_Proto)
1106         break;
1107       while (CurrentToken &&
1108              !CurrentToken->isOneOf(tok::l_paren, tok::semi, tok::r_paren)) {
1109         if (CurrentToken->isOneOf(tok::star, tok::amp))
1110           CurrentToken->setType(TT_PointerOrReference);
1111         consumeToken();
1112         if (CurrentToken && CurrentToken->is(tok::comma) &&
1113             CurrentToken->Previous->isNot(tok::kw_operator))
1114           break;
1115         if (CurrentToken && CurrentToken->Previous->isOneOf(
1116                                 TT_BinaryOperator, TT_UnaryOperator, tok::comma,
1117                                 tok::star, tok::arrow, tok::amp, tok::ampamp))
1118           CurrentToken->Previous->setType(TT_OverloadedOperator);
1119       }
1120       if (CurrentToken && CurrentToken->is(tok::l_paren))
1121         CurrentToken->setType(TT_OverloadedOperatorLParen);
1122       if (CurrentToken && CurrentToken->Previous->is(TT_BinaryOperator))
1123         CurrentToken->Previous->setType(TT_OverloadedOperator);
1124       break;
1125     case tok::question:
1126       if (Style.isJavaScript() && Tok->Next &&
1127           Tok->Next->isOneOf(tok::semi, tok::comma, tok::colon, tok::r_paren,
1128                              tok::r_brace)) {
1129         // Question marks before semicolons, colons, etc. indicate optional
1130         // types (fields, parameters), e.g.
1131         //   function(x?: string, y?) {...}
1132         //   class X { y?; }
1133         Tok->setType(TT_JsTypeOptionalQuestion);
1134         break;
1135       }
1136       // Declarations cannot be conditional expressions, this can only be part
1137       // of a type declaration.
1138       if (Line.MustBeDeclaration && !Contexts.back().IsExpression &&
1139           Style.isJavaScript())
1140         break;
1141       if (Style.isCSharp()) {
1142         // `Type?)`, `Type?>`, `Type? name;` and `Type? name =` can only be
1143         // nullable types.
1144         // Line.MustBeDeclaration will be true for `Type? name;`.
1145         if ((!Contexts.back().IsExpression && Line.MustBeDeclaration) ||
1146             (Tok->Next && Tok->Next->isOneOf(tok::r_paren, tok::greater)) ||
1147             (Tok->Next && Tok->Next->is(tok::identifier) && Tok->Next->Next &&
1148              Tok->Next->Next->is(tok::equal))) {
1149           Tok->setType(TT_CSharpNullable);
1150           break;
1151         }
1152       }
1153       parseConditional();
1154       break;
1155     case tok::kw_template:
1156       parseTemplateDeclaration();
1157       break;
1158     case tok::comma:
1159       switch (Contexts.back().ContextType) {
1160       case Context::CtorInitializer:
1161         Tok->setType(TT_CtorInitializerComma);
1162         break;
1163       case Context::InheritanceList:
1164         Tok->setType(TT_InheritanceComma);
1165         break;
1166       default:
1167         if (Contexts.back().FirstStartOfName &&
1168             (Contexts.size() == 1 || startsWithInitStatement(Line))) {
1169           Contexts.back().FirstStartOfName->PartOfMultiVariableDeclStmt = true;
1170           Line.IsMultiVariableDeclStmt = true;
1171         }
1172         break;
1173       }
1174       if (Contexts.back().ContextType == Context::ForEachMacro)
1175         Contexts.back().IsExpression = true;
1176       break;
1177     case tok::identifier:
1178       if (Tok->isOneOf(Keywords.kw___has_include,
1179                        Keywords.kw___has_include_next))
1180         parseHasInclude();
1181       if (Style.isCSharp() && Tok->is(Keywords.kw_where) && Tok->Next &&
1182           Tok->Next->isNot(tok::l_paren)) {
1183         Tok->setType(TT_CSharpGenericTypeConstraint);
1184         parseCSharpGenericTypeConstraint();
1185       }
1186       break;
1187     case tok::arrow:
1188       if (Tok->isNot(TT_LambdaArrow) && Tok->Previous &&
1189           Tok->Previous->is(tok::kw_noexcept))
1190         Tok->setType(TT_TrailingReturnArrow);
1191       break;
1192     default:
1193       break;
1194     }
1195     return true;
1196   }
1197 
1198   void parseCSharpGenericTypeConstraint() {
1199     int OpenAngleBracketsCount = 0;
1200     while (CurrentToken) {
1201       if (CurrentToken->is(tok::less)) {
1202         // parseAngle is too greedy and will consume the whole line.
1203         CurrentToken->setType(TT_TemplateOpener);
1204         ++OpenAngleBracketsCount;
1205         next();
1206       } else if (CurrentToken->is(tok::greater)) {
1207         CurrentToken->setType(TT_TemplateCloser);
1208         --OpenAngleBracketsCount;
1209         next();
1210       } else if (CurrentToken->is(tok::comma) && OpenAngleBracketsCount == 0) {
1211         // We allow line breaks after GenericTypeConstraintComma's
1212         // so do not flag commas in Generics as GenericTypeConstraintComma's.
1213         CurrentToken->setType(TT_CSharpGenericTypeConstraintComma);
1214         next();
1215       } else if (CurrentToken->is(Keywords.kw_where)) {
1216         CurrentToken->setType(TT_CSharpGenericTypeConstraint);
1217         next();
1218       } else if (CurrentToken->is(tok::colon)) {
1219         CurrentToken->setType(TT_CSharpGenericTypeConstraintColon);
1220         next();
1221       } else {
1222         next();
1223       }
1224     }
1225   }
1226 
1227   void parseIncludeDirective() {
1228     if (CurrentToken && CurrentToken->is(tok::less)) {
1229       next();
1230       while (CurrentToken) {
1231         // Mark tokens up to the trailing line comments as implicit string
1232         // literals.
1233         if (CurrentToken->isNot(tok::comment) &&
1234             !CurrentToken->TokenText.startswith("//"))
1235           CurrentToken->setType(TT_ImplicitStringLiteral);
1236         next();
1237       }
1238     }
1239   }
1240 
1241   void parseWarningOrError() {
1242     next();
1243     // We still want to format the whitespace left of the first token of the
1244     // warning or error.
1245     next();
1246     while (CurrentToken) {
1247       CurrentToken->setType(TT_ImplicitStringLiteral);
1248       next();
1249     }
1250   }
1251 
1252   void parsePragma() {
1253     next(); // Consume "pragma".
1254     if (CurrentToken &&
1255         CurrentToken->isOneOf(Keywords.kw_mark, Keywords.kw_option, Keywords.kw_region)) {
1256       bool IsMark = CurrentToken->is(Keywords.kw_mark);
1257       next();
1258       next(); // Consume first token (so we fix leading whitespace).
1259       while (CurrentToken) {
1260         if (IsMark || CurrentToken->Previous->is(TT_BinaryOperator))
1261           CurrentToken->setType(TT_ImplicitStringLiteral);
1262         next();
1263       }
1264     }
1265   }
1266 
1267   void parseHasInclude() {
1268     if (!CurrentToken || !CurrentToken->is(tok::l_paren))
1269       return;
1270     next(); // '('
1271     parseIncludeDirective();
1272     next(); // ')'
1273   }
1274 
1275   LineType parsePreprocessorDirective() {
1276     bool IsFirstToken = CurrentToken->IsFirst;
1277     LineType Type = LT_PreprocessorDirective;
1278     next();
1279     if (!CurrentToken)
1280       return Type;
1281 
1282     if (Style.isJavaScript() && IsFirstToken) {
1283       // JavaScript files can contain shebang lines of the form:
1284       // #!/usr/bin/env node
1285       // Treat these like C++ #include directives.
1286       while (CurrentToken) {
1287         // Tokens cannot be comments here.
1288         CurrentToken->setType(TT_ImplicitStringLiteral);
1289         next();
1290       }
1291       return LT_ImportStatement;
1292     }
1293 
1294     if (CurrentToken->is(tok::numeric_constant)) {
1295       CurrentToken->SpacesRequiredBefore = 1;
1296       return Type;
1297     }
1298     // Hashes in the middle of a line can lead to any strange token
1299     // sequence.
1300     if (!CurrentToken->Tok.getIdentifierInfo())
1301       return Type;
1302     switch (CurrentToken->Tok.getIdentifierInfo()->getPPKeywordID()) {
1303     case tok::pp_include:
1304     case tok::pp_include_next:
1305     case tok::pp_import:
1306       next();
1307       parseIncludeDirective();
1308       Type = LT_ImportStatement;
1309       break;
1310     case tok::pp_error:
1311     case tok::pp_warning:
1312       parseWarningOrError();
1313       break;
1314     case tok::pp_pragma:
1315       parsePragma();
1316       break;
1317     case tok::pp_if:
1318     case tok::pp_elif:
1319       Contexts.back().IsExpression = true;
1320       next();
1321       parseLine();
1322       break;
1323     default:
1324       break;
1325     }
1326     while (CurrentToken) {
1327       FormatToken *Tok = CurrentToken;
1328       next();
1329       if (Tok->is(tok::l_paren))
1330         parseParens();
1331       else if (Tok->isOneOf(Keywords.kw___has_include,
1332                             Keywords.kw___has_include_next))
1333         parseHasInclude();
1334     }
1335     return Type;
1336   }
1337 
1338 public:
1339   LineType parseLine() {
1340     if (!CurrentToken)
1341       return LT_Invalid;
1342     NonTemplateLess.clear();
1343     if (CurrentToken->is(tok::hash))
1344       return parsePreprocessorDirective();
1345 
1346     // Directly allow to 'import <string-literal>' to support protocol buffer
1347     // definitions (github.com/google/protobuf) or missing "#" (either way we
1348     // should not break the line).
1349     IdentifierInfo *Info = CurrentToken->Tok.getIdentifierInfo();
1350     if ((Style.Language == FormatStyle::LK_Java &&
1351          CurrentToken->is(Keywords.kw_package)) ||
1352         (Info && Info->getPPKeywordID() == tok::pp_import &&
1353          CurrentToken->Next &&
1354          CurrentToken->Next->isOneOf(tok::string_literal, tok::identifier,
1355                                      tok::kw_static))) {
1356       next();
1357       parseIncludeDirective();
1358       return LT_ImportStatement;
1359     }
1360 
1361     // If this line starts and ends in '<' and '>', respectively, it is likely
1362     // part of "#define <a/b.h>".
1363     if (CurrentToken->is(tok::less) && Line.Last->is(tok::greater)) {
1364       parseIncludeDirective();
1365       return LT_ImportStatement;
1366     }
1367 
1368     // In .proto files, top-level options and package statements are very
1369     // similar to import statements and should not be line-wrapped.
1370     if (Style.Language == FormatStyle::LK_Proto && Line.Level == 0 &&
1371         CurrentToken->isOneOf(Keywords.kw_option, Keywords.kw_package)) {
1372       next();
1373       if (CurrentToken && CurrentToken->is(tok::identifier)) {
1374         while (CurrentToken)
1375           next();
1376         return LT_ImportStatement;
1377       }
1378     }
1379 
1380     bool KeywordVirtualFound = false;
1381     bool ImportStatement = false;
1382 
1383     // import {...} from '...';
1384     if (Style.isJavaScript() && CurrentToken->is(Keywords.kw_import))
1385       ImportStatement = true;
1386 
1387     while (CurrentToken) {
1388       if (CurrentToken->is(tok::kw_virtual))
1389         KeywordVirtualFound = true;
1390       if (Style.isJavaScript()) {
1391         // export {...} from '...';
1392         // An export followed by "from 'some string';" is a re-export from
1393         // another module identified by a URI and is treated as a
1394         // LT_ImportStatement (i.e. prevent wraps on it for long URIs).
1395         // Just "export {...};" or "export class ..." should not be treated as
1396         // an import in this sense.
1397         if (Line.First->is(tok::kw_export) &&
1398             CurrentToken->is(Keywords.kw_from) && CurrentToken->Next &&
1399             CurrentToken->Next->isStringLiteral())
1400           ImportStatement = true;
1401         if (isClosureImportStatement(*CurrentToken))
1402           ImportStatement = true;
1403       }
1404       if (!consumeToken())
1405         return LT_Invalid;
1406     }
1407     if (KeywordVirtualFound)
1408       return LT_VirtualFunctionDecl;
1409     if (ImportStatement)
1410       return LT_ImportStatement;
1411 
1412     if (Line.startsWith(TT_ObjCMethodSpecifier)) {
1413       if (Contexts.back().FirstObjCSelectorName)
1414         Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
1415             Contexts.back().LongestObjCSelectorName;
1416       return LT_ObjCMethodDecl;
1417     }
1418 
1419     for (const auto &ctx : Contexts)
1420       if (ctx.ContextType == Context::StructArrayInitializer)
1421         return LT_ArrayOfStructInitializer;
1422 
1423     return LT_Other;
1424   }
1425 
1426 private:
1427   bool isClosureImportStatement(const FormatToken &Tok) {
1428     // FIXME: Closure-library specific stuff should not be hard-coded but be
1429     // configurable.
1430     return Tok.TokenText == "goog" && Tok.Next && Tok.Next->is(tok::period) &&
1431            Tok.Next->Next &&
1432            (Tok.Next->Next->TokenText == "module" ||
1433             Tok.Next->Next->TokenText == "provide" ||
1434             Tok.Next->Next->TokenText == "require" ||
1435             Tok.Next->Next->TokenText == "requireType" ||
1436             Tok.Next->Next->TokenText == "forwardDeclare") &&
1437            Tok.Next->Next->Next && Tok.Next->Next->Next->is(tok::l_paren);
1438   }
1439 
1440   void resetTokenMetadata() {
1441     if (!CurrentToken)
1442       return;
1443 
1444     // Reset token type in case we have already looked at it and then
1445     // recovered from an error (e.g. failure to find the matching >).
1446     if (!CurrentToken->isTypeFinalized() &&
1447         !CurrentToken->isOneOf(
1448             TT_LambdaLSquare, TT_LambdaLBrace, TT_AttributeMacro, TT_IfMacro,
1449             TT_ForEachMacro, TT_TypenameMacro, TT_FunctionLBrace,
1450             TT_ImplicitStringLiteral, TT_InlineASMBrace, TT_FatArrow,
1451             TT_LambdaArrow, TT_NamespaceMacro, TT_OverloadedOperator,
1452             TT_RegexLiteral, TT_TemplateString, TT_ObjCStringLiteral,
1453             TT_UntouchableMacroFunc, TT_StatementAttributeLikeMacro,
1454             TT_FunctionLikeOrFreestandingMacro, TT_ClassLBrace, TT_EnumLBrace,
1455             TT_RecordLBrace, TT_StructLBrace, TT_UnionLBrace, TT_RequiresClause,
1456             TT_RequiresClauseInARequiresExpression, TT_RequiresExpression,
1457             TT_RequiresExpressionLParen, TT_RequiresExpressionLBrace,
1458             TT_CompoundRequirementLBrace, TT_BracedListLBrace))
1459       CurrentToken->setType(TT_Unknown);
1460     CurrentToken->Role.reset();
1461     CurrentToken->MatchingParen = nullptr;
1462     CurrentToken->FakeLParens.clear();
1463     CurrentToken->FakeRParens = 0;
1464   }
1465 
1466   void next() {
1467     if (!CurrentToken)
1468       return;
1469 
1470     CurrentToken->NestingLevel = Contexts.size() - 1;
1471     CurrentToken->BindingStrength = Contexts.back().BindingStrength;
1472     modifyContext(*CurrentToken);
1473     determineTokenType(*CurrentToken);
1474     CurrentToken = CurrentToken->Next;
1475 
1476     resetTokenMetadata();
1477   }
1478 
1479   /// A struct to hold information valid in a specific context, e.g.
1480   /// a pair of parenthesis.
1481   struct Context {
1482     Context(tok::TokenKind ContextKind, unsigned BindingStrength,
1483             bool IsExpression)
1484         : ContextKind(ContextKind), BindingStrength(BindingStrength),
1485           IsExpression(IsExpression) {}
1486 
1487     tok::TokenKind ContextKind;
1488     unsigned BindingStrength;
1489     bool IsExpression;
1490     unsigned LongestObjCSelectorName = 0;
1491     bool ColonIsForRangeExpr = false;
1492     bool ColonIsDictLiteral = false;
1493     bool ColonIsObjCMethodExpr = false;
1494     FormatToken *FirstObjCSelectorName = nullptr;
1495     FormatToken *FirstStartOfName = nullptr;
1496     bool CanBeExpression = true;
1497     bool CaretFound = false;
1498     bool InCpp11AttributeSpecifier = false;
1499     bool InCSharpAttributeSpecifier = false;
1500     enum {
1501       Unknown,
1502       // Like the part after `:` in a constructor.
1503       //   Context(...) : IsExpression(IsExpression)
1504       CtorInitializer,
1505       // Like in the parentheses in a foreach.
1506       ForEachMacro,
1507       // Like the inheritance list in a class declaration.
1508       //   class Input : public IO
1509       InheritanceList,
1510       // Like in the braced list.
1511       //   int x[] = {};
1512       StructArrayInitializer,
1513       // Like in `static_cast<int>`.
1514       TemplateArgument,
1515     } ContextType = Unknown;
1516   };
1517 
1518   /// Puts a new \c Context onto the stack \c Contexts for the lifetime
1519   /// of each instance.
1520   struct ScopedContextCreator {
1521     AnnotatingParser &P;
1522 
1523     ScopedContextCreator(AnnotatingParser &P, tok::TokenKind ContextKind,
1524                          unsigned Increase)
1525         : P(P) {
1526       P.Contexts.push_back(Context(ContextKind,
1527                                    P.Contexts.back().BindingStrength + Increase,
1528                                    P.Contexts.back().IsExpression));
1529     }
1530 
1531     ~ScopedContextCreator() {
1532       if (P.Style.AlignArrayOfStructures != FormatStyle::AIAS_None) {
1533         if (P.Contexts.back().ContextType == Context::StructArrayInitializer) {
1534           P.Contexts.pop_back();
1535           P.Contexts.back().ContextType = Context::StructArrayInitializer;
1536           return;
1537         }
1538       }
1539       P.Contexts.pop_back();
1540     }
1541   };
1542 
1543   void modifyContext(const FormatToken &Current) {
1544     auto AssignmentStartsExpression = [&]() {
1545       if (Current.getPrecedence() != prec::Assignment)
1546         return false;
1547 
1548       if (Line.First->isOneOf(tok::kw_using, tok::kw_return))
1549         return false;
1550       if (Line.First->is(tok::kw_template)) {
1551         assert(Current.Previous);
1552         if (Current.Previous->is(tok::kw_operator)) {
1553           // `template ... operator=` cannot be an expression.
1554           return false;
1555         }
1556 
1557         // `template` keyword can start a variable template.
1558         const FormatToken *Tok = Line.First->getNextNonComment();
1559         assert(Tok); // Current token is on the same line.
1560         if (Tok->isNot(TT_TemplateOpener)) {
1561           // Explicit template instantiations do not have `<>`.
1562           return false;
1563         }
1564 
1565         Tok = Tok->MatchingParen;
1566         if (!Tok)
1567           return false;
1568         Tok = Tok->getNextNonComment();
1569         if (!Tok)
1570           return false;
1571 
1572         if (Tok->isOneOf(tok::kw_class, tok::kw_enum, tok::kw_concept,
1573                          tok::kw_struct, tok::kw_using))
1574           return false;
1575 
1576         return true;
1577       }
1578 
1579       // Type aliases use `type X = ...;` in TypeScript and can be exported
1580       // using `export type ...`.
1581       if (Style.isJavaScript() &&
1582           (Line.startsWith(Keywords.kw_type, tok::identifier) ||
1583            Line.startsWith(tok::kw_export, Keywords.kw_type, tok::identifier)))
1584         return false;
1585 
1586       return !Current.Previous || Current.Previous->isNot(tok::kw_operator);
1587     };
1588 
1589     if (AssignmentStartsExpression()) {
1590       Contexts.back().IsExpression = true;
1591       if (!Line.startsWith(TT_UnaryOperator)) {
1592         for (FormatToken *Previous = Current.Previous;
1593              Previous && Previous->Previous &&
1594              !Previous->Previous->isOneOf(tok::comma, tok::semi);
1595              Previous = Previous->Previous) {
1596           if (Previous->isOneOf(tok::r_square, tok::r_paren)) {
1597             Previous = Previous->MatchingParen;
1598             if (!Previous)
1599               break;
1600           }
1601           if (Previous->opensScope())
1602             break;
1603           if (Previous->isOneOf(TT_BinaryOperator, TT_UnaryOperator) &&
1604               Previous->isOneOf(tok::star, tok::amp, tok::ampamp) &&
1605               Previous->Previous && Previous->Previous->isNot(tok::equal))
1606             Previous->setType(TT_PointerOrReference);
1607         }
1608       }
1609     } else if (Current.is(tok::lessless) &&
1610                (!Current.Previous || !Current.Previous->is(tok::kw_operator))) {
1611       Contexts.back().IsExpression = true;
1612     } else if (Current.isOneOf(tok::kw_return, tok::kw_throw)) {
1613       Contexts.back().IsExpression = true;
1614     } else if (Current.is(TT_TrailingReturnArrow)) {
1615       Contexts.back().IsExpression = false;
1616     } else if (Current.is(TT_LambdaArrow) || Current.is(Keywords.kw_assert)) {
1617       Contexts.back().IsExpression = Style.Language == FormatStyle::LK_Java;
1618     } else if (Current.Previous &&
1619                Current.Previous->is(TT_CtorInitializerColon)) {
1620       Contexts.back().IsExpression = true;
1621       Contexts.back().ContextType = Context::CtorInitializer;
1622     } else if (Current.Previous && Current.Previous->is(TT_InheritanceColon)) {
1623       Contexts.back().ContextType = Context::InheritanceList;
1624     } else if (Current.isOneOf(tok::r_paren, tok::greater, tok::comma)) {
1625       for (FormatToken *Previous = Current.Previous;
1626            Previous && Previous->isOneOf(tok::star, tok::amp);
1627            Previous = Previous->Previous)
1628         Previous->setType(TT_PointerOrReference);
1629       if (Line.MustBeDeclaration &&
1630           Contexts.front().ContextType != Context::CtorInitializer)
1631         Contexts.back().IsExpression = false;
1632     } else if (Current.is(tok::kw_new)) {
1633       Contexts.back().CanBeExpression = false;
1634     } else if (Current.is(tok::semi) ||
1635                (Current.is(tok::exclaim) && Current.Previous &&
1636                 !Current.Previous->is(tok::kw_operator))) {
1637       // This should be the condition or increment in a for-loop.
1638       // But not operator !() (can't use TT_OverloadedOperator here as its not
1639       // been annotated yet).
1640       Contexts.back().IsExpression = true;
1641     }
1642   }
1643 
1644   static FormatToken *untilMatchingParen(FormatToken *Current) {
1645     // Used when `MatchingParen` is not yet established.
1646     int ParenLevel = 0;
1647     while (Current) {
1648       if (Current->is(tok::l_paren))
1649         ++ParenLevel;
1650       if (Current->is(tok::r_paren))
1651         --ParenLevel;
1652       if (ParenLevel < 1)
1653         break;
1654       Current = Current->Next;
1655     }
1656     return Current;
1657   }
1658 
1659   static bool isDeductionGuide(FormatToken &Current) {
1660     // Look for a deduction guide template<T> A(...) -> A<...>;
1661     if (Current.Previous && Current.Previous->is(tok::r_paren) &&
1662         Current.startsSequence(tok::arrow, tok::identifier, tok::less)) {
1663       // Find the TemplateCloser.
1664       FormatToken *TemplateCloser = Current.Next->Next;
1665       int NestingLevel = 0;
1666       while (TemplateCloser) {
1667         // Skip over an expressions in parens  A<(3 < 2)>;
1668         if (TemplateCloser->is(tok::l_paren)) {
1669           // No Matching Paren yet so skip to matching paren
1670           TemplateCloser = untilMatchingParen(TemplateCloser);
1671           if (!TemplateCloser)
1672             break;
1673         }
1674         if (TemplateCloser->is(tok::less))
1675           ++NestingLevel;
1676         if (TemplateCloser->is(tok::greater))
1677           --NestingLevel;
1678         if (NestingLevel < 1)
1679           break;
1680         TemplateCloser = TemplateCloser->Next;
1681       }
1682       // Assuming we have found the end of the template ensure its followed
1683       // with a semi-colon.
1684       if (TemplateCloser && TemplateCloser->Next &&
1685           TemplateCloser->Next->is(tok::semi) &&
1686           Current.Previous->MatchingParen) {
1687         // Determine if the identifier `A` prior to the A<..>; is the same as
1688         // prior to the A(..)
1689         FormatToken *LeadingIdentifier =
1690             Current.Previous->MatchingParen->Previous;
1691 
1692         // Differentiate a deduction guide by seeing the
1693         // > of the template prior to the leading identifier.
1694         if (LeadingIdentifier) {
1695           FormatToken *PriorLeadingIdentifier = LeadingIdentifier->Previous;
1696           // Skip back past explicit decoration
1697           if (PriorLeadingIdentifier &&
1698               PriorLeadingIdentifier->is(tok::kw_explicit))
1699             PriorLeadingIdentifier = PriorLeadingIdentifier->Previous;
1700 
1701           return PriorLeadingIdentifier &&
1702                  (PriorLeadingIdentifier->is(TT_TemplateCloser) ||
1703                   PriorLeadingIdentifier->ClosesRequiresClause) &&
1704                  LeadingIdentifier->TokenText == Current.Next->TokenText;
1705         }
1706       }
1707     }
1708     return false;
1709   }
1710 
1711   void determineTokenType(FormatToken &Current) {
1712     if (!Current.is(TT_Unknown))
1713       // The token type is already known.
1714       return;
1715 
1716     if ((Style.isJavaScript() || Style.isCSharp()) &&
1717         Current.is(tok::exclaim)) {
1718       if (Current.Previous) {
1719         bool IsIdentifier =
1720             Style.isJavaScript()
1721                 ? Keywords.IsJavaScriptIdentifier(
1722                       *Current.Previous, /* AcceptIdentifierName= */ true)
1723                 : Current.Previous->is(tok::identifier);
1724         if (IsIdentifier ||
1725             Current.Previous->isOneOf(
1726                 tok::kw_default, tok::kw_namespace, tok::r_paren, tok::r_square,
1727                 tok::r_brace, tok::kw_false, tok::kw_true, Keywords.kw_type,
1728                 Keywords.kw_get, Keywords.kw_init, Keywords.kw_set) ||
1729             Current.Previous->Tok.isLiteral()) {
1730           Current.setType(TT_NonNullAssertion);
1731           return;
1732         }
1733       }
1734       if (Current.Next &&
1735           Current.Next->isOneOf(TT_BinaryOperator, Keywords.kw_as)) {
1736         Current.setType(TT_NonNullAssertion);
1737         return;
1738       }
1739     }
1740 
1741     // Line.MightBeFunctionDecl can only be true after the parentheses of a
1742     // function declaration have been found. In this case, 'Current' is a
1743     // trailing token of this declaration and thus cannot be a name.
1744     if (Current.is(Keywords.kw_instanceof)) {
1745       Current.setType(TT_BinaryOperator);
1746     } else if (isStartOfName(Current) &&
1747                (!Line.MightBeFunctionDecl || Current.NestingLevel != 0)) {
1748       Contexts.back().FirstStartOfName = &Current;
1749       Current.setType(TT_StartOfName);
1750     } else if (Current.is(tok::semi)) {
1751       // Reset FirstStartOfName after finding a semicolon so that a for loop
1752       // with multiple increment statements is not confused with a for loop
1753       // having multiple variable declarations.
1754       Contexts.back().FirstStartOfName = nullptr;
1755     } else if (Current.isOneOf(tok::kw_auto, tok::kw___auto_type)) {
1756       AutoFound = true;
1757     } else if (Current.is(tok::arrow) &&
1758                Style.Language == FormatStyle::LK_Java) {
1759       Current.setType(TT_LambdaArrow);
1760     } else if (Current.is(tok::arrow) && AutoFound && Line.MustBeDeclaration &&
1761                Current.NestingLevel == 0 &&
1762                !Current.Previous->isOneOf(tok::kw_operator, tok::identifier)) {
1763       // not auto operator->() -> xxx;
1764       Current.setType(TT_TrailingReturnArrow);
1765     } else if (Current.is(tok::arrow) && Current.Previous &&
1766                Current.Previous->is(tok::r_brace)) {
1767       // Concept implicit conversion constraint needs to be treated like
1768       // a trailing return type  ... } -> <type>.
1769       Current.setType(TT_TrailingReturnArrow);
1770     } else if (isDeductionGuide(Current)) {
1771       // Deduction guides trailing arrow " A(...) -> A<T>;".
1772       Current.setType(TT_TrailingReturnArrow);
1773     } else if (Current.isOneOf(tok::star, tok::amp, tok::ampamp)) {
1774       Current.setType(determineStarAmpUsage(
1775           Current,
1776           Contexts.back().CanBeExpression && Contexts.back().IsExpression,
1777           Contexts.back().ContextType == Context::TemplateArgument));
1778     } else if (Current.isOneOf(tok::minus, tok::plus, tok::caret)) {
1779       Current.setType(determinePlusMinusCaretUsage(Current));
1780       if (Current.is(TT_UnaryOperator) && Current.is(tok::caret))
1781         Contexts.back().CaretFound = true;
1782     } else if (Current.isOneOf(tok::minusminus, tok::plusplus)) {
1783       Current.setType(determineIncrementUsage(Current));
1784     } else if (Current.isOneOf(tok::exclaim, tok::tilde)) {
1785       Current.setType(TT_UnaryOperator);
1786     } else if (Current.is(tok::question)) {
1787       if (Style.isJavaScript() && Line.MustBeDeclaration &&
1788           !Contexts.back().IsExpression) {
1789         // In JavaScript, `interface X { foo?(): bar; }` is an optional method
1790         // on the interface, not a ternary expression.
1791         Current.setType(TT_JsTypeOptionalQuestion);
1792       } else {
1793         Current.setType(TT_ConditionalExpr);
1794       }
1795     } else if (Current.isBinaryOperator() &&
1796                (!Current.Previous || Current.Previous->isNot(tok::l_square)) &&
1797                (!Current.is(tok::greater) &&
1798                 Style.Language != FormatStyle::LK_TextProto)) {
1799       Current.setType(TT_BinaryOperator);
1800     } else if (Current.is(tok::comment)) {
1801       if (Current.TokenText.startswith("/*"))
1802         if (Current.TokenText.endswith("*/"))
1803           Current.setType(TT_BlockComment);
1804         else
1805           // The lexer has for some reason determined a comment here. But we
1806           // cannot really handle it, if it isn't properly terminated.
1807           Current.Tok.setKind(tok::unknown);
1808       else
1809         Current.setType(TT_LineComment);
1810     } else if (Current.is(tok::l_paren)) {
1811       if (lParenStartsCppCast(Current))
1812         Current.setType(TT_CppCastLParen);
1813     } else if (Current.is(tok::r_paren)) {
1814       if (rParenEndsCast(Current))
1815         Current.setType(TT_CastRParen);
1816       if (Current.MatchingParen && Current.Next &&
1817           !Current.Next->isBinaryOperator() &&
1818           !Current.Next->isOneOf(tok::semi, tok::colon, tok::l_brace,
1819                                  tok::comma, tok::period, tok::arrow,
1820                                  tok::coloncolon))
1821         if (FormatToken *AfterParen = Current.MatchingParen->Next) {
1822           // Make sure this isn't the return type of an Obj-C block declaration
1823           if (AfterParen->isNot(tok::caret)) {
1824             if (FormatToken *BeforeParen = Current.MatchingParen->Previous)
1825               if (BeforeParen->is(tok::identifier) &&
1826                   !BeforeParen->is(TT_TypenameMacro) &&
1827                   BeforeParen->TokenText == BeforeParen->TokenText.upper() &&
1828                   (!BeforeParen->Previous ||
1829                    BeforeParen->Previous->ClosesTemplateDeclaration))
1830                 Current.setType(TT_FunctionAnnotationRParen);
1831           }
1832         }
1833     } else if (Current.is(tok::at) && Current.Next && !Style.isJavaScript() &&
1834                Style.Language != FormatStyle::LK_Java) {
1835       // In Java & JavaScript, "@..." is a decorator or annotation. In ObjC, it
1836       // marks declarations and properties that need special formatting.
1837       switch (Current.Next->Tok.getObjCKeywordID()) {
1838       case tok::objc_interface:
1839       case tok::objc_implementation:
1840       case tok::objc_protocol:
1841         Current.setType(TT_ObjCDecl);
1842         break;
1843       case tok::objc_property:
1844         Current.setType(TT_ObjCProperty);
1845         break;
1846       default:
1847         break;
1848       }
1849     } else if (Current.is(tok::period)) {
1850       FormatToken *PreviousNoComment = Current.getPreviousNonComment();
1851       if (PreviousNoComment &&
1852           PreviousNoComment->isOneOf(tok::comma, tok::l_brace))
1853         Current.setType(TT_DesignatedInitializerPeriod);
1854       else if (Style.Language == FormatStyle::LK_Java && Current.Previous &&
1855                Current.Previous->isOneOf(TT_JavaAnnotation,
1856                                          TT_LeadingJavaAnnotation))
1857         Current.setType(Current.Previous->getType());
1858     } else if (canBeObjCSelectorComponent(Current) &&
1859                // FIXME(bug 36976): ObjC return types shouldn't use
1860                // TT_CastRParen.
1861                Current.Previous && Current.Previous->is(TT_CastRParen) &&
1862                Current.Previous->MatchingParen &&
1863                Current.Previous->MatchingParen->Previous &&
1864                Current.Previous->MatchingParen->Previous->is(
1865                    TT_ObjCMethodSpecifier)) {
1866       // This is the first part of an Objective-C selector name. (If there's no
1867       // colon after this, this is the only place which annotates the identifier
1868       // as a selector.)
1869       Current.setType(TT_SelectorName);
1870     } else if (Current.isOneOf(tok::identifier, tok::kw_const, tok::kw_noexcept,
1871                                tok::kw_requires) &&
1872                Current.Previous &&
1873                !Current.Previous->isOneOf(tok::equal, tok::at) &&
1874                Line.MightBeFunctionDecl && Contexts.size() == 1) {
1875       // Line.MightBeFunctionDecl can only be true after the parentheses of a
1876       // function declaration have been found.
1877       Current.setType(TT_TrailingAnnotation);
1878     } else if ((Style.Language == FormatStyle::LK_Java ||
1879                 Style.isJavaScript()) &&
1880                Current.Previous) {
1881       if (Current.Previous->is(tok::at) &&
1882           Current.isNot(Keywords.kw_interface)) {
1883         const FormatToken &AtToken = *Current.Previous;
1884         const FormatToken *Previous = AtToken.getPreviousNonComment();
1885         if (!Previous || Previous->is(TT_LeadingJavaAnnotation))
1886           Current.setType(TT_LeadingJavaAnnotation);
1887         else
1888           Current.setType(TT_JavaAnnotation);
1889       } else if (Current.Previous->is(tok::period) &&
1890                  Current.Previous->isOneOf(TT_JavaAnnotation,
1891                                            TT_LeadingJavaAnnotation)) {
1892         Current.setType(Current.Previous->getType());
1893       }
1894     }
1895   }
1896 
1897   /// Take a guess at whether \p Tok starts a name of a function or
1898   /// variable declaration.
1899   ///
1900   /// This is a heuristic based on whether \p Tok is an identifier following
1901   /// something that is likely a type.
1902   bool isStartOfName(const FormatToken &Tok) {
1903     if (Tok.isNot(tok::identifier) || !Tok.Previous)
1904       return false;
1905 
1906     if (Tok.Previous->isOneOf(TT_LeadingJavaAnnotation, Keywords.kw_instanceof,
1907                               Keywords.kw_as))
1908       return false;
1909     if (Style.isJavaScript() && Tok.Previous->is(Keywords.kw_in))
1910       return false;
1911 
1912     // Skip "const" as it does not have an influence on whether this is a name.
1913     FormatToken *PreviousNotConst = Tok.getPreviousNonComment();
1914 
1915     // For javascript const can be like "let" or "var"
1916     if (!Style.isJavaScript())
1917       while (PreviousNotConst && PreviousNotConst->is(tok::kw_const))
1918         PreviousNotConst = PreviousNotConst->getPreviousNonComment();
1919 
1920     if (!PreviousNotConst)
1921       return false;
1922 
1923     if (PreviousNotConst->ClosesRequiresClause)
1924       return false;
1925 
1926     bool IsPPKeyword = PreviousNotConst->is(tok::identifier) &&
1927                        PreviousNotConst->Previous &&
1928                        PreviousNotConst->Previous->is(tok::hash);
1929 
1930     if (PreviousNotConst->is(TT_TemplateCloser))
1931       return PreviousNotConst && PreviousNotConst->MatchingParen &&
1932              PreviousNotConst->MatchingParen->Previous &&
1933              PreviousNotConst->MatchingParen->Previous->isNot(tok::period) &&
1934              PreviousNotConst->MatchingParen->Previous->isNot(tok::kw_template);
1935 
1936     if (PreviousNotConst->is(tok::r_paren) &&
1937         PreviousNotConst->is(TT_TypeDeclarationParen))
1938       return true;
1939 
1940     // If is a preprocess keyword like #define.
1941     if (IsPPKeyword)
1942       return false;
1943 
1944     // int a or auto a.
1945     if (PreviousNotConst->isOneOf(tok::identifier, tok::kw_auto))
1946       return true;
1947 
1948     // *a or &a or &&a.
1949     if (PreviousNotConst->is(TT_PointerOrReference))
1950       return true;
1951 
1952     // MyClass a;
1953     if (PreviousNotConst->isSimpleTypeSpecifier())
1954       return true;
1955 
1956     // const a = in JavaScript.
1957     return Style.isJavaScript() && PreviousNotConst->is(tok::kw_const);
1958   }
1959 
1960   /// Determine whether '(' is starting a C++ cast.
1961   bool lParenStartsCppCast(const FormatToken &Tok) {
1962     // C-style casts are only used in C++.
1963     if (!Style.isCpp())
1964       return false;
1965 
1966     FormatToken *LeftOfParens = Tok.getPreviousNonComment();
1967     if (LeftOfParens && LeftOfParens->is(TT_TemplateCloser) &&
1968         LeftOfParens->MatchingParen) {
1969       auto *Prev = LeftOfParens->MatchingParen->getPreviousNonComment();
1970       if (Prev && Prev->isOneOf(tok::kw_const_cast, tok::kw_dynamic_cast,
1971                                 tok::kw_reinterpret_cast, tok::kw_static_cast))
1972         // FIXME: Maybe we should handle identifiers ending with "_cast",
1973         // e.g. any_cast?
1974         return true;
1975     }
1976     return false;
1977   }
1978 
1979   /// Determine whether ')' is ending a cast.
1980   bool rParenEndsCast(const FormatToken &Tok) {
1981     // C-style casts are only used in C++, C# and Java.
1982     if (!Style.isCSharp() && !Style.isCpp() &&
1983         Style.Language != FormatStyle::LK_Java)
1984       return false;
1985 
1986     // Empty parens aren't casts and there are no casts at the end of the line.
1987     if (Tok.Previous == Tok.MatchingParen || !Tok.Next || !Tok.MatchingParen)
1988       return false;
1989 
1990     FormatToken *LeftOfParens = Tok.MatchingParen->getPreviousNonComment();
1991     if (LeftOfParens) {
1992       // If there is a closing parenthesis left of the current
1993       // parentheses, look past it as these might be chained casts.
1994       if (LeftOfParens->is(tok::r_paren) &&
1995           LeftOfParens->isNot(TT_CastRParen)) {
1996         if (!LeftOfParens->MatchingParen ||
1997             !LeftOfParens->MatchingParen->Previous)
1998           return false;
1999         LeftOfParens = LeftOfParens->MatchingParen->Previous;
2000       }
2001 
2002       if (LeftOfParens->is(tok::r_square)) {
2003         //   delete[] (void *)ptr;
2004         auto MayBeArrayDelete = [](FormatToken *Tok) -> FormatToken * {
2005           if (Tok->isNot(tok::r_square))
2006             return nullptr;
2007 
2008           Tok = Tok->getPreviousNonComment();
2009           if (!Tok || Tok->isNot(tok::l_square))
2010             return nullptr;
2011 
2012           Tok = Tok->getPreviousNonComment();
2013           if (!Tok || Tok->isNot(tok::kw_delete))
2014             return nullptr;
2015           return Tok;
2016         };
2017         if (FormatToken *MaybeDelete = MayBeArrayDelete(LeftOfParens))
2018           LeftOfParens = MaybeDelete;
2019       }
2020 
2021       // The Condition directly below this one will see the operator arguments
2022       // as a (void *foo) cast.
2023       //   void operator delete(void *foo) ATTRIB;
2024       if (LeftOfParens->Tok.getIdentifierInfo() && LeftOfParens->Previous &&
2025           LeftOfParens->Previous->is(tok::kw_operator))
2026         return false;
2027 
2028       // If there is an identifier (or with a few exceptions a keyword) right
2029       // before the parentheses, this is unlikely to be a cast.
2030       if (LeftOfParens->Tok.getIdentifierInfo() &&
2031           !LeftOfParens->isOneOf(Keywords.kw_in, tok::kw_return, tok::kw_case,
2032                                  tok::kw_delete))
2033         return false;
2034 
2035       // Certain other tokens right before the parentheses are also signals that
2036       // this cannot be a cast.
2037       if (LeftOfParens->isOneOf(tok::at, tok::r_square, TT_OverloadedOperator,
2038                                 TT_TemplateCloser, tok::ellipsis))
2039         return false;
2040     }
2041 
2042     if (Tok.Next->is(tok::question))
2043       return false;
2044 
2045     // `foreach((A a, B b) in someList)` should not be seen as a cast.
2046     if (Tok.Next->is(Keywords.kw_in) && Style.isCSharp())
2047       return false;
2048 
2049     // Functions which end with decorations like volatile, noexcept are unlikely
2050     // to be casts.
2051     if (Tok.Next->isOneOf(tok::kw_noexcept, tok::kw_volatile, tok::kw_const,
2052                           tok::kw_requires, tok::kw_throw, tok::arrow,
2053                           Keywords.kw_override, Keywords.kw_final) ||
2054         isCpp11AttributeSpecifier(*Tok.Next))
2055       return false;
2056 
2057     // As Java has no function types, a "(" after the ")" likely means that this
2058     // is a cast.
2059     if (Style.Language == FormatStyle::LK_Java && Tok.Next->is(tok::l_paren))
2060       return true;
2061 
2062     // If a (non-string) literal follows, this is likely a cast.
2063     if (Tok.Next->isNot(tok::string_literal) &&
2064         (Tok.Next->Tok.isLiteral() ||
2065          Tok.Next->isOneOf(tok::kw_sizeof, tok::kw_alignof)))
2066       return true;
2067 
2068     // Heuristically try to determine whether the parentheses contain a type.
2069     auto IsQualifiedPointerOrReference = [](FormatToken *T) {
2070       // This is used to handle cases such as x = (foo *const)&y;
2071       assert(!T->isSimpleTypeSpecifier() && "Should have already been checked");
2072       // Strip trailing qualifiers such as const or volatile when checking
2073       // whether the parens could be a cast to a pointer/reference type.
2074       while (T) {
2075         if (T->is(TT_AttributeParen)) {
2076           // Handle `x = (foo *__attribute__((foo)))&v;`:
2077           if (T->MatchingParen && T->MatchingParen->Previous &&
2078               T->MatchingParen->Previous->is(tok::kw___attribute)) {
2079             T = T->MatchingParen->Previous->Previous;
2080             continue;
2081           }
2082         } else if (T->is(TT_AttributeSquare)) {
2083           // Handle `x = (foo *[[clang::foo]])&v;`:
2084           if (T->MatchingParen && T->MatchingParen->Previous) {
2085             T = T->MatchingParen->Previous;
2086             continue;
2087           }
2088         } else if (T->canBePointerOrReferenceQualifier()) {
2089           T = T->Previous;
2090           continue;
2091         }
2092         break;
2093       }
2094       return T && T->is(TT_PointerOrReference);
2095     };
2096     bool ParensAreType =
2097         !Tok.Previous ||
2098         Tok.Previous->isOneOf(TT_TemplateCloser, TT_TypeDeclarationParen) ||
2099         Tok.Previous->isSimpleTypeSpecifier() ||
2100         IsQualifiedPointerOrReference(Tok.Previous);
2101     bool ParensCouldEndDecl =
2102         Tok.Next->isOneOf(tok::equal, tok::semi, tok::l_brace, tok::greater);
2103     if (ParensAreType && !ParensCouldEndDecl)
2104       return true;
2105 
2106     // At this point, we heuristically assume that there are no casts at the
2107     // start of the line. We assume that we have found most cases where there
2108     // are by the logic above, e.g. "(void)x;".
2109     if (!LeftOfParens)
2110       return false;
2111 
2112     // Certain token types inside the parentheses mean that this can't be a
2113     // cast.
2114     for (const FormatToken *Token = Tok.MatchingParen->Next; Token != &Tok;
2115          Token = Token->Next)
2116       if (Token->is(TT_BinaryOperator))
2117         return false;
2118 
2119     // If the following token is an identifier or 'this', this is a cast. All
2120     // cases where this can be something else are handled above.
2121     if (Tok.Next->isOneOf(tok::identifier, tok::kw_this))
2122       return true;
2123 
2124     // Look for a cast `( x ) (`.
2125     if (Tok.Next->is(tok::l_paren) && Tok.Previous && Tok.Previous->Previous) {
2126       if (Tok.Previous->is(tok::identifier) &&
2127           Tok.Previous->Previous->is(tok::l_paren))
2128         return true;
2129     }
2130 
2131     if (!Tok.Next->Next)
2132       return false;
2133 
2134     // If the next token after the parenthesis is a unary operator, assume
2135     // that this is cast, unless there are unexpected tokens inside the
2136     // parenthesis.
2137     bool NextIsUnary =
2138         Tok.Next->isUnaryOperator() || Tok.Next->isOneOf(tok::amp, tok::star);
2139     if (!NextIsUnary || Tok.Next->is(tok::plus) ||
2140         !Tok.Next->Next->isOneOf(tok::identifier, tok::numeric_constant))
2141       return false;
2142     // Search for unexpected tokens.
2143     for (FormatToken *Prev = Tok.Previous; Prev != Tok.MatchingParen;
2144          Prev = Prev->Previous)
2145       if (!Prev->isOneOf(tok::kw_const, tok::identifier, tok::coloncolon))
2146         return false;
2147     return true;
2148   }
2149 
2150   /// Returns true if the token is used as a unary operator.
2151   bool determineUnaryOperatorByUsage(const FormatToken &Tok) {
2152     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2153     if (!PrevToken)
2154       return true;
2155 
2156     // These keywords are deliberately not included here because they may
2157     // precede only one of unary star/amp and plus/minus but not both.  They are
2158     // either included in determineStarAmpUsage or determinePlusMinusCaretUsage.
2159     //
2160     // @ - It may be followed by a unary `-` in Objective-C literals. We don't
2161     //   know how they can be followed by a star or amp.
2162     if (PrevToken->isOneOf(
2163             TT_ConditionalExpr, tok::l_paren, tok::comma, tok::colon, tok::semi,
2164             tok::equal, tok::question, tok::l_square, tok::l_brace,
2165             tok::kw_case, tok::kw_co_await, tok::kw_co_return, tok::kw_co_yield,
2166             tok::kw_delete, tok::kw_return, tok::kw_throw))
2167       return true;
2168 
2169     // We put sizeof here instead of only in determineStarAmpUsage. In the cases
2170     // where the unary `+` operator is overloaded, it is reasonable to write
2171     // things like `sizeof +x`. Like commit 446d6ec996c6c3.
2172     if (PrevToken->is(tok::kw_sizeof))
2173       return true;
2174 
2175     // A sequence of leading unary operators.
2176     if (PrevToken->isOneOf(TT_CastRParen, TT_UnaryOperator))
2177       return true;
2178 
2179     // There can't be two consecutive binary operators.
2180     if (PrevToken->is(TT_BinaryOperator))
2181       return true;
2182 
2183     return false;
2184   }
2185 
2186   /// Return the type of the given token assuming it is * or &.
2187   TokenType determineStarAmpUsage(const FormatToken &Tok, bool IsExpression,
2188                                   bool InTemplateArgument) {
2189     if (Style.isJavaScript())
2190       return TT_BinaryOperator;
2191 
2192     // && in C# must be a binary operator.
2193     if (Style.isCSharp() && Tok.is(tok::ampamp))
2194       return TT_BinaryOperator;
2195 
2196     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2197     if (!PrevToken)
2198       return TT_UnaryOperator;
2199 
2200     const FormatToken *NextToken = Tok.getNextNonComment();
2201 
2202     if (InTemplateArgument && NextToken && NextToken->is(tok::kw_noexcept))
2203       return TT_BinaryOperator;
2204 
2205     if (!NextToken ||
2206         NextToken->isOneOf(tok::arrow, tok::equal, tok::kw_noexcept) ||
2207         NextToken->canBePointerOrReferenceQualifier() ||
2208         (NextToken->is(tok::l_brace) && !NextToken->getNextNonComment()))
2209       return TT_PointerOrReference;
2210 
2211     if (PrevToken->is(tok::coloncolon))
2212       return TT_PointerOrReference;
2213 
2214     if (PrevToken->is(tok::r_paren) && PrevToken->is(TT_TypeDeclarationParen))
2215       return TT_PointerOrReference;
2216 
2217     if (determineUnaryOperatorByUsage(Tok))
2218       return TT_UnaryOperator;
2219 
2220     if (NextToken->is(tok::l_square) && NextToken->isNot(TT_LambdaLSquare))
2221       return TT_PointerOrReference;
2222     if (NextToken->is(tok::kw_operator) && !IsExpression)
2223       return TT_PointerOrReference;
2224     if (NextToken->isOneOf(tok::comma, tok::semi))
2225       return TT_PointerOrReference;
2226 
2227     if (PrevToken->Tok.isLiteral() ||
2228         PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::kw_true,
2229                            tok::kw_false, tok::r_brace))
2230       return TT_BinaryOperator;
2231 
2232     const FormatToken *NextNonParen = NextToken;
2233     while (NextNonParen && NextNonParen->is(tok::l_paren))
2234       NextNonParen = NextNonParen->getNextNonComment();
2235     if (NextNonParen && (NextNonParen->Tok.isLiteral() ||
2236                          NextNonParen->isOneOf(tok::kw_true, tok::kw_false) ||
2237                          NextNonParen->isUnaryOperator()))
2238       return TT_BinaryOperator;
2239 
2240     // If we know we're in a template argument, there are no named declarations.
2241     // Thus, having an identifier on the right-hand side indicates a binary
2242     // operator.
2243     if (InTemplateArgument && NextToken->Tok.isAnyIdentifier())
2244       return TT_BinaryOperator;
2245 
2246     // "&&(" is quite unlikely to be two successive unary "&".
2247     if (Tok.is(tok::ampamp) && NextToken->is(tok::l_paren))
2248       return TT_BinaryOperator;
2249 
2250     // This catches some cases where evaluation order is used as control flow:
2251     //   aaa && aaa->f();
2252     if (NextToken->Tok.isAnyIdentifier()) {
2253       const FormatToken *NextNextToken = NextToken->getNextNonComment();
2254       if (NextNextToken && NextNextToken->is(tok::arrow))
2255         return TT_BinaryOperator;
2256     }
2257 
2258     // It is very unlikely that we are going to find a pointer or reference type
2259     // definition on the RHS of an assignment.
2260     if (IsExpression && !Contexts.back().CaretFound)
2261       return TT_BinaryOperator;
2262 
2263     return TT_PointerOrReference;
2264   }
2265 
2266   TokenType determinePlusMinusCaretUsage(const FormatToken &Tok) {
2267     if (determineUnaryOperatorByUsage(Tok))
2268       return TT_UnaryOperator;
2269 
2270     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2271     if (!PrevToken)
2272       return TT_UnaryOperator;
2273 
2274     if (PrevToken->is(tok::at))
2275       return TT_UnaryOperator;
2276 
2277     // Fall back to marking the token as binary operator.
2278     return TT_BinaryOperator;
2279   }
2280 
2281   /// Determine whether ++/-- are pre- or post-increments/-decrements.
2282   TokenType determineIncrementUsage(const FormatToken &Tok) {
2283     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2284     if (!PrevToken || PrevToken->is(TT_CastRParen))
2285       return TT_UnaryOperator;
2286     if (PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::identifier))
2287       return TT_TrailingUnaryOperator;
2288 
2289     return TT_UnaryOperator;
2290   }
2291 
2292   SmallVector<Context, 8> Contexts;
2293 
2294   const FormatStyle &Style;
2295   AnnotatedLine &Line;
2296   FormatToken *CurrentToken;
2297   bool AutoFound;
2298   const AdditionalKeywords &Keywords;
2299 
2300   // Set of "<" tokens that do not open a template parameter list. If parseAngle
2301   // determines that a specific token can't be a template opener, it will make
2302   // same decision irrespective of the decisions for tokens leading up to it.
2303   // Store this information to prevent this from causing exponential runtime.
2304   llvm::SmallPtrSet<FormatToken *, 16> NonTemplateLess;
2305 };
2306 
2307 static const int PrecedenceUnaryOperator = prec::PointerToMember + 1;
2308 static const int PrecedenceArrowAndPeriod = prec::PointerToMember + 2;
2309 
2310 /// Parses binary expressions by inserting fake parenthesis based on
2311 /// operator precedence.
2312 class ExpressionParser {
2313 public:
2314   ExpressionParser(const FormatStyle &Style, const AdditionalKeywords &Keywords,
2315                    AnnotatedLine &Line)
2316       : Style(Style), Keywords(Keywords), Line(Line), Current(Line.First) {}
2317 
2318   /// Parse expressions with the given operator precedence.
2319   void parse(int Precedence = 0) {
2320     // Skip 'return' and ObjC selector colons as they are not part of a binary
2321     // expression.
2322     while (Current && (Current->is(tok::kw_return) ||
2323                        (Current->is(tok::colon) &&
2324                         Current->isOneOf(TT_ObjCMethodExpr, TT_DictLiteral))))
2325       next();
2326 
2327     if (!Current || Precedence > PrecedenceArrowAndPeriod)
2328       return;
2329 
2330     // Conditional expressions need to be parsed separately for proper nesting.
2331     if (Precedence == prec::Conditional) {
2332       parseConditionalExpr();
2333       return;
2334     }
2335 
2336     // Parse unary operators, which all have a higher precedence than binary
2337     // operators.
2338     if (Precedence == PrecedenceUnaryOperator) {
2339       parseUnaryOperator();
2340       return;
2341     }
2342 
2343     FormatToken *Start = Current;
2344     FormatToken *LatestOperator = nullptr;
2345     unsigned OperatorIndex = 0;
2346 
2347     while (Current) {
2348       // Consume operators with higher precedence.
2349       parse(Precedence + 1);
2350 
2351       int CurrentPrecedence = getCurrentPrecedence();
2352 
2353       if (Precedence == CurrentPrecedence && Current &&
2354           Current->is(TT_SelectorName)) {
2355         if (LatestOperator)
2356           addFakeParenthesis(Start, prec::Level(Precedence));
2357         Start = Current;
2358       }
2359 
2360       // At the end of the line or when an operator with higher precedence is
2361       // found, insert fake parenthesis and return.
2362       if (!Current ||
2363           (Current->closesScope() &&
2364            (Current->MatchingParen || Current->is(TT_TemplateString))) ||
2365           (CurrentPrecedence != -1 && CurrentPrecedence < Precedence) ||
2366           (CurrentPrecedence == prec::Conditional &&
2367            Precedence == prec::Assignment && Current->is(tok::colon)))
2368         break;
2369 
2370       // Consume scopes: (), [], <> and {}
2371       // In addition to that we handle require clauses as scope, so that the
2372       // constraints in that are correctly indented.
2373       if (Current->opensScope() ||
2374           Current->isOneOf(TT_RequiresClause,
2375                            TT_RequiresClauseInARequiresExpression)) {
2376         // In fragment of a JavaScript template string can look like '}..${' and
2377         // thus close a scope and open a new one at the same time.
2378         while (Current && (!Current->closesScope() || Current->opensScope())) {
2379           next();
2380           parse();
2381         }
2382         next();
2383       } else {
2384         // Operator found.
2385         if (CurrentPrecedence == Precedence) {
2386           if (LatestOperator)
2387             LatestOperator->NextOperator = Current;
2388           LatestOperator = Current;
2389           Current->OperatorIndex = OperatorIndex;
2390           ++OperatorIndex;
2391         }
2392         next(/*SkipPastLeadingComments=*/Precedence > 0);
2393       }
2394     }
2395 
2396     if (LatestOperator && (Current || Precedence > 0)) {
2397       // The requires clauses do not neccessarily end in a semicolon or a brace,
2398       // but just go over to struct/class or a function declaration, we need to
2399       // intervene so that the fake right paren is inserted correctly.
2400       auto End =
2401           (Start->Previous &&
2402            Start->Previous->isOneOf(TT_RequiresClause,
2403                                     TT_RequiresClauseInARequiresExpression))
2404               ? [this](){
2405                   auto Ret = Current ? Current : Line.Last;
2406                   while (!Ret->ClosesRequiresClause && Ret->Previous)
2407                     Ret = Ret->Previous;
2408                   return Ret;
2409                 }()
2410               : nullptr;
2411 
2412       if (Precedence == PrecedenceArrowAndPeriod) {
2413         // Call expressions don't have a binary operator precedence.
2414         addFakeParenthesis(Start, prec::Unknown, End);
2415       } else {
2416         addFakeParenthesis(Start, prec::Level(Precedence), End);
2417       }
2418     }
2419   }
2420 
2421 private:
2422   /// Gets the precedence (+1) of the given token for binary operators
2423   /// and other tokens that we treat like binary operators.
2424   int getCurrentPrecedence() {
2425     if (Current) {
2426       const FormatToken *NextNonComment = Current->getNextNonComment();
2427       if (Current->is(TT_ConditionalExpr))
2428         return prec::Conditional;
2429       if (NextNonComment && Current->is(TT_SelectorName) &&
2430           (NextNonComment->isOneOf(TT_DictLiteral, TT_JsTypeColon) ||
2431            ((Style.Language == FormatStyle::LK_Proto ||
2432              Style.Language == FormatStyle::LK_TextProto) &&
2433             NextNonComment->is(tok::less))))
2434         return prec::Assignment;
2435       if (Current->is(TT_JsComputedPropertyName))
2436         return prec::Assignment;
2437       if (Current->is(TT_LambdaArrow))
2438         return prec::Comma;
2439       if (Current->is(TT_FatArrow))
2440         return prec::Assignment;
2441       if (Current->isOneOf(tok::semi, TT_InlineASMColon, TT_SelectorName) ||
2442           (Current->is(tok::comment) && NextNonComment &&
2443            NextNonComment->is(TT_SelectorName)))
2444         return 0;
2445       if (Current->is(TT_RangeBasedForLoopColon))
2446         return prec::Comma;
2447       if ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
2448           Current->is(Keywords.kw_instanceof))
2449         return prec::Relational;
2450       if (Style.isJavaScript() &&
2451           Current->isOneOf(Keywords.kw_in, Keywords.kw_as))
2452         return prec::Relational;
2453       if (Current->is(TT_BinaryOperator) || Current->is(tok::comma))
2454         return Current->getPrecedence();
2455       if (Current->isOneOf(tok::period, tok::arrow))
2456         return PrecedenceArrowAndPeriod;
2457       if ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
2458           Current->isOneOf(Keywords.kw_extends, Keywords.kw_implements,
2459                            Keywords.kw_throws))
2460         return 0;
2461     }
2462     return -1;
2463   }
2464 
2465   void addFakeParenthesis(FormatToken *Start, prec::Level Precedence,
2466                           FormatToken *End = nullptr) {
2467     Start->FakeLParens.push_back(Precedence);
2468     if (Precedence > prec::Unknown)
2469       Start->StartsBinaryExpression = true;
2470     if (!End && Current)
2471       End = Current->getPreviousNonComment();
2472     if (End) {
2473       ++End->FakeRParens;
2474       if (Precedence > prec::Unknown)
2475         End->EndsBinaryExpression = true;
2476     }
2477   }
2478 
2479   /// Parse unary operator expressions and surround them with fake
2480   /// parentheses if appropriate.
2481   void parseUnaryOperator() {
2482     llvm::SmallVector<FormatToken *, 2> Tokens;
2483     while (Current && Current->is(TT_UnaryOperator)) {
2484       Tokens.push_back(Current);
2485       next();
2486     }
2487     parse(PrecedenceArrowAndPeriod);
2488     for (FormatToken *Token : llvm::reverse(Tokens))
2489       // The actual precedence doesn't matter.
2490       addFakeParenthesis(Token, prec::Unknown);
2491   }
2492 
2493   void parseConditionalExpr() {
2494     while (Current && Current->isTrailingComment())
2495       next();
2496     FormatToken *Start = Current;
2497     parse(prec::LogicalOr);
2498     if (!Current || !Current->is(tok::question))
2499       return;
2500     next();
2501     parse(prec::Assignment);
2502     if (!Current || Current->isNot(TT_ConditionalExpr))
2503       return;
2504     next();
2505     parse(prec::Assignment);
2506     addFakeParenthesis(Start, prec::Conditional);
2507   }
2508 
2509   void next(bool SkipPastLeadingComments = true) {
2510     if (Current)
2511       Current = Current->Next;
2512     while (Current &&
2513            (Current->NewlinesBefore == 0 || SkipPastLeadingComments) &&
2514            Current->isTrailingComment())
2515       Current = Current->Next;
2516   }
2517 
2518   const FormatStyle &Style;
2519   const AdditionalKeywords &Keywords;
2520   const AnnotatedLine &Line;
2521   FormatToken *Current;
2522 };
2523 
2524 } // end anonymous namespace
2525 
2526 void TokenAnnotator::setCommentLineLevels(
2527     SmallVectorImpl<AnnotatedLine *> &Lines) const {
2528   const AnnotatedLine *NextNonCommentLine = nullptr;
2529   for (AnnotatedLine *Line : llvm::reverse(Lines)) {
2530     assert(Line->First);
2531 
2532     // If the comment is currently aligned with the line immediately following
2533     // it, that's probably intentional and we should keep it.
2534     if (NextNonCommentLine && Line->isComment() &&
2535         NextNonCommentLine->First->NewlinesBefore <= 1 &&
2536         NextNonCommentLine->First->OriginalColumn ==
2537             Line->First->OriginalColumn) {
2538       // Align comments for preprocessor lines with the # in column 0 if
2539       // preprocessor lines are not indented. Otherwise, align with the next
2540       // line.
2541       Line->Level =
2542           (Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
2543            (NextNonCommentLine->Type == LT_PreprocessorDirective ||
2544             NextNonCommentLine->Type == LT_ImportStatement))
2545               ? 0
2546               : NextNonCommentLine->Level;
2547     } else {
2548       NextNonCommentLine = Line->First->isNot(tok::r_brace) ? Line : nullptr;
2549     }
2550 
2551     setCommentLineLevels(Line->Children);
2552   }
2553 }
2554 
2555 static unsigned maxNestingDepth(const AnnotatedLine &Line) {
2556   unsigned Result = 0;
2557   for (const auto *Tok = Line.First; Tok != nullptr; Tok = Tok->Next)
2558     Result = std::max(Result, Tok->NestingLevel);
2559   return Result;
2560 }
2561 
2562 void TokenAnnotator::annotate(AnnotatedLine &Line) const {
2563   for (auto &Child : Line.Children)
2564     annotate(*Child);
2565 
2566   AnnotatingParser Parser(Style, Line, Keywords);
2567   Line.Type = Parser.parseLine();
2568 
2569   // With very deep nesting, ExpressionParser uses lots of stack and the
2570   // formatting algorithm is very slow. We're not going to do a good job here
2571   // anyway - it's probably generated code being formatted by mistake.
2572   // Just skip the whole line.
2573   if (maxNestingDepth(Line) > 50)
2574     Line.Type = LT_Invalid;
2575 
2576   if (Line.Type == LT_Invalid)
2577     return;
2578 
2579   ExpressionParser ExprParser(Style, Keywords, Line);
2580   ExprParser.parse();
2581 
2582   if (Line.startsWith(TT_ObjCMethodSpecifier))
2583     Line.Type = LT_ObjCMethodDecl;
2584   else if (Line.startsWith(TT_ObjCDecl))
2585     Line.Type = LT_ObjCDecl;
2586   else if (Line.startsWith(TT_ObjCProperty))
2587     Line.Type = LT_ObjCProperty;
2588 
2589   Line.First->SpacesRequiredBefore = 1;
2590   Line.First->CanBreakBefore = Line.First->MustBreakBefore;
2591 }
2592 
2593 // This function heuristically determines whether 'Current' starts the name of a
2594 // function declaration.
2595 static bool isFunctionDeclarationName(bool IsCpp, const FormatToken &Current,
2596                                       const AnnotatedLine &Line) {
2597   auto skipOperatorName = [](const FormatToken *Next) -> const FormatToken * {
2598     for (; Next; Next = Next->Next) {
2599       if (Next->is(TT_OverloadedOperatorLParen))
2600         return Next;
2601       if (Next->is(TT_OverloadedOperator))
2602         continue;
2603       if (Next->isOneOf(tok::kw_new, tok::kw_delete)) {
2604         // For 'new[]' and 'delete[]'.
2605         if (Next->Next &&
2606             Next->Next->startsSequence(tok::l_square, tok::r_square))
2607           Next = Next->Next->Next;
2608         continue;
2609       }
2610       if (Next->startsSequence(tok::l_square, tok::r_square)) {
2611         // For operator[]().
2612         Next = Next->Next;
2613         continue;
2614       }
2615       if ((Next->isSimpleTypeSpecifier() || Next->is(tok::identifier)) &&
2616           Next->Next && Next->Next->isOneOf(tok::star, tok::amp, tok::ampamp)) {
2617         // For operator void*(), operator char*(), operator Foo*().
2618         Next = Next->Next;
2619         continue;
2620       }
2621       if (Next->is(TT_TemplateOpener) && Next->MatchingParen) {
2622         Next = Next->MatchingParen;
2623         continue;
2624       }
2625 
2626       break;
2627     }
2628     return nullptr;
2629   };
2630 
2631   // Find parentheses of parameter list.
2632   const FormatToken *Next = Current.Next;
2633   if (Current.is(tok::kw_operator)) {
2634     if (Current.Previous && Current.Previous->is(tok::coloncolon))
2635       return false;
2636     Next = skipOperatorName(Next);
2637   } else {
2638     if (!Current.is(TT_StartOfName) || Current.NestingLevel != 0)
2639       return false;
2640     for (; Next; Next = Next->Next) {
2641       if (Next->is(TT_TemplateOpener)) {
2642         Next = Next->MatchingParen;
2643       } else if (Next->is(tok::coloncolon)) {
2644         Next = Next->Next;
2645         if (!Next)
2646           return false;
2647         if (Next->is(tok::kw_operator)) {
2648           Next = skipOperatorName(Next->Next);
2649           break;
2650         }
2651         if (!Next->is(tok::identifier))
2652           return false;
2653       } else if (Next->is(tok::l_paren)) {
2654         break;
2655       } else {
2656         return false;
2657       }
2658     }
2659   }
2660 
2661   // Check whether parameter list can belong to a function declaration.
2662   if (!Next || !Next->is(tok::l_paren) || !Next->MatchingParen)
2663     return false;
2664   // If the lines ends with "{", this is likely a function definition.
2665   if (Line.Last->is(tok::l_brace))
2666     return true;
2667   if (Next->Next == Next->MatchingParen)
2668     return true; // Empty parentheses.
2669   // If there is an &/&& after the r_paren, this is likely a function.
2670   if (Next->MatchingParen->Next &&
2671       Next->MatchingParen->Next->is(TT_PointerOrReference))
2672     return true;
2673 
2674   // Check for K&R C function definitions (and C++ function definitions with
2675   // unnamed parameters), e.g.:
2676   //   int f(i)
2677   //   {
2678   //     return i + 1;
2679   //   }
2680   //   bool g(size_t = 0, bool b = false)
2681   //   {
2682   //     return !b;
2683   //   }
2684   if (IsCpp && Next->Next && Next->Next->is(tok::identifier) &&
2685       !Line.endsWith(tok::semi))
2686     return true;
2687 
2688   for (const FormatToken *Tok = Next->Next; Tok && Tok != Next->MatchingParen;
2689        Tok = Tok->Next) {
2690     if (Tok->is(TT_TypeDeclarationParen))
2691       return true;
2692     if (Tok->isOneOf(tok::l_paren, TT_TemplateOpener) && Tok->MatchingParen) {
2693       Tok = Tok->MatchingParen;
2694       continue;
2695     }
2696     if (Tok->is(tok::kw_const) || Tok->isSimpleTypeSpecifier() ||
2697         Tok->isOneOf(TT_PointerOrReference, TT_StartOfName, tok::ellipsis))
2698       return true;
2699     if (Tok->isOneOf(tok::l_brace, tok::string_literal, TT_ObjCMethodExpr) ||
2700         Tok->Tok.isLiteral())
2701       return false;
2702   }
2703   return false;
2704 }
2705 
2706 bool TokenAnnotator::mustBreakForReturnType(const AnnotatedLine &Line) const {
2707   assert(Line.MightBeFunctionDecl);
2708 
2709   if ((Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_TopLevel ||
2710        Style.AlwaysBreakAfterReturnType ==
2711            FormatStyle::RTBS_TopLevelDefinitions) &&
2712       Line.Level > 0)
2713     return false;
2714 
2715   switch (Style.AlwaysBreakAfterReturnType) {
2716   case FormatStyle::RTBS_None:
2717     return false;
2718   case FormatStyle::RTBS_All:
2719   case FormatStyle::RTBS_TopLevel:
2720     return true;
2721   case FormatStyle::RTBS_AllDefinitions:
2722   case FormatStyle::RTBS_TopLevelDefinitions:
2723     return Line.mightBeFunctionDefinition();
2724   }
2725 
2726   return false;
2727 }
2728 
2729 void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) const {
2730   for (AnnotatedLine *ChildLine : Line.Children)
2731     calculateFormattingInformation(*ChildLine);
2732 
2733   Line.First->TotalLength =
2734       Line.First->IsMultiline ? Style.ColumnLimit
2735                               : Line.FirstStartColumn + Line.First->ColumnWidth;
2736   FormatToken *Current = Line.First->Next;
2737   bool InFunctionDecl = Line.MightBeFunctionDecl;
2738   bool AlignArrayOfStructures =
2739       (Style.AlignArrayOfStructures != FormatStyle::AIAS_None &&
2740        Line.Type == LT_ArrayOfStructInitializer);
2741   if (AlignArrayOfStructures)
2742     calculateArrayInitializerColumnList(Line);
2743 
2744   while (Current) {
2745     if (isFunctionDeclarationName(Style.isCpp(), *Current, Line))
2746       Current->setType(TT_FunctionDeclarationName);
2747     const FormatToken *Prev = Current->Previous;
2748     if (Current->is(TT_LineComment)) {
2749       if (Prev->is(BK_BracedInit) && Prev->opensScope())
2750         Current->SpacesRequiredBefore =
2751             (Style.Cpp11BracedListStyle && !Style.SpacesInParentheses) ? 0 : 1;
2752       else
2753         Current->SpacesRequiredBefore = Style.SpacesBeforeTrailingComments;
2754 
2755       // If we find a trailing comment, iterate backwards to determine whether
2756       // it seems to relate to a specific parameter. If so, break before that
2757       // parameter to avoid changing the comment's meaning. E.g. don't move 'b'
2758       // to the previous line in:
2759       //   SomeFunction(a,
2760       //                b, // comment
2761       //                c);
2762       if (!Current->HasUnescapedNewline) {
2763         for (FormatToken *Parameter = Current->Previous; Parameter;
2764              Parameter = Parameter->Previous) {
2765           if (Parameter->isOneOf(tok::comment, tok::r_brace))
2766             break;
2767           if (Parameter->Previous && Parameter->Previous->is(tok::comma)) {
2768             if (!Parameter->Previous->is(TT_CtorInitializerComma) &&
2769                 Parameter->HasUnescapedNewline)
2770               Parameter->MustBreakBefore = true;
2771             break;
2772           }
2773         }
2774       }
2775     } else if (Current->SpacesRequiredBefore == 0 &&
2776                spaceRequiredBefore(Line, *Current)) {
2777       Current->SpacesRequiredBefore = 1;
2778     }
2779 
2780     const auto &Children = Prev->Children;
2781     if (!Children.empty() && Children.back()->Last->is(TT_LineComment)) {
2782       Current->MustBreakBefore = true;
2783     } else {
2784       Current->MustBreakBefore =
2785           Current->MustBreakBefore || mustBreakBefore(Line, *Current);
2786       if (!Current->MustBreakBefore && InFunctionDecl &&
2787           Current->is(TT_FunctionDeclarationName))
2788         Current->MustBreakBefore = mustBreakForReturnType(Line);
2789     }
2790 
2791     Current->CanBreakBefore =
2792         Current->MustBreakBefore || canBreakBefore(Line, *Current);
2793     unsigned ChildSize = 0;
2794     if (Prev->Children.size() == 1) {
2795       FormatToken &LastOfChild = *Prev->Children[0]->Last;
2796       ChildSize = LastOfChild.isTrailingComment() ? Style.ColumnLimit
2797                                                   : LastOfChild.TotalLength + 1;
2798     }
2799     if (Current->MustBreakBefore || Prev->Children.size() > 1 ||
2800         (Prev->Children.size() == 1 &&
2801          Prev->Children[0]->First->MustBreakBefore) ||
2802         Current->IsMultiline)
2803       Current->TotalLength = Prev->TotalLength + Style.ColumnLimit;
2804     else
2805       Current->TotalLength = Prev->TotalLength + Current->ColumnWidth +
2806                              ChildSize + Current->SpacesRequiredBefore;
2807 
2808     if (Current->is(TT_CtorInitializerColon))
2809       InFunctionDecl = false;
2810 
2811     // FIXME: Only calculate this if CanBreakBefore is true once static
2812     // initializers etc. are sorted out.
2813     // FIXME: Move magic numbers to a better place.
2814 
2815     // Reduce penalty for aligning ObjC method arguments using the colon
2816     // alignment as this is the canonical way (still prefer fitting everything
2817     // into one line if possible). Trying to fit a whole expression into one
2818     // line should not force other line breaks (e.g. when ObjC method
2819     // expression is a part of other expression).
2820     Current->SplitPenalty = splitPenalty(Line, *Current, InFunctionDecl);
2821     if (Style.Language == FormatStyle::LK_ObjC &&
2822         Current->is(TT_SelectorName) && Current->ParameterIndex > 0) {
2823       if (Current->ParameterIndex == 1)
2824         Current->SplitPenalty += 5 * Current->BindingStrength;
2825     } else {
2826       Current->SplitPenalty += 20 * Current->BindingStrength;
2827     }
2828 
2829     Current = Current->Next;
2830   }
2831 
2832   calculateUnbreakableTailLengths(Line);
2833   unsigned IndentLevel = Line.Level;
2834   for (Current = Line.First; Current != nullptr; Current = Current->Next) {
2835     if (Current->Role)
2836       Current->Role->precomputeFormattingInfos(Current);
2837     if (Current->MatchingParen &&
2838         Current->MatchingParen->opensBlockOrBlockTypeList(Style) &&
2839         IndentLevel > 0)
2840       --IndentLevel;
2841     Current->IndentLevel = IndentLevel;
2842     if (Current->opensBlockOrBlockTypeList(Style))
2843       ++IndentLevel;
2844   }
2845 
2846   LLVM_DEBUG({ printDebugInfo(Line); });
2847 }
2848 
2849 void TokenAnnotator::calculateUnbreakableTailLengths(
2850     AnnotatedLine &Line) const {
2851   unsigned UnbreakableTailLength = 0;
2852   FormatToken *Current = Line.Last;
2853   while (Current) {
2854     Current->UnbreakableTailLength = UnbreakableTailLength;
2855     if (Current->CanBreakBefore ||
2856         Current->isOneOf(tok::comment, tok::string_literal)) {
2857       UnbreakableTailLength = 0;
2858     } else {
2859       UnbreakableTailLength +=
2860           Current->ColumnWidth + Current->SpacesRequiredBefore;
2861     }
2862     Current = Current->Previous;
2863   }
2864 }
2865 
2866 void TokenAnnotator::calculateArrayInitializerColumnList(
2867     AnnotatedLine &Line) const {
2868   if (Line.First == Line.Last)
2869     return;
2870   auto *CurrentToken = Line.First;
2871   CurrentToken->ArrayInitializerLineStart = true;
2872   unsigned Depth = 0;
2873   while (CurrentToken != nullptr && CurrentToken != Line.Last) {
2874     if (CurrentToken->is(tok::l_brace)) {
2875       CurrentToken->IsArrayInitializer = true;
2876       if (CurrentToken->Next != nullptr)
2877         CurrentToken->Next->MustBreakBefore = true;
2878       CurrentToken =
2879           calculateInitializerColumnList(Line, CurrentToken->Next, Depth + 1);
2880     } else {
2881       CurrentToken = CurrentToken->Next;
2882     }
2883   }
2884 }
2885 
2886 FormatToken *TokenAnnotator::calculateInitializerColumnList(
2887     AnnotatedLine &Line, FormatToken *CurrentToken, unsigned Depth) const {
2888   while (CurrentToken != nullptr && CurrentToken != Line.Last) {
2889     if (CurrentToken->is(tok::l_brace))
2890       ++Depth;
2891     else if (CurrentToken->is(tok::r_brace))
2892       --Depth;
2893     if (Depth == 2 && CurrentToken->isOneOf(tok::l_brace, tok::comma)) {
2894       CurrentToken = CurrentToken->Next;
2895       if (CurrentToken == nullptr)
2896         break;
2897       CurrentToken->StartsColumn = true;
2898       CurrentToken = CurrentToken->Previous;
2899     }
2900     CurrentToken = CurrentToken->Next;
2901   }
2902   return CurrentToken;
2903 }
2904 
2905 unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
2906                                       const FormatToken &Tok,
2907                                       bool InFunctionDecl) const {
2908   const FormatToken &Left = *Tok.Previous;
2909   const FormatToken &Right = Tok;
2910 
2911   if (Left.is(tok::semi))
2912     return 0;
2913 
2914   if (Style.Language == FormatStyle::LK_Java) {
2915     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_throws))
2916       return 1;
2917     if (Right.is(Keywords.kw_implements))
2918       return 2;
2919     if (Left.is(tok::comma) && Left.NestingLevel == 0)
2920       return 3;
2921   } else if (Style.isJavaScript()) {
2922     if (Right.is(Keywords.kw_function) && Left.isNot(tok::comma))
2923       return 100;
2924     if (Left.is(TT_JsTypeColon))
2925       return 35;
2926     if ((Left.is(TT_TemplateString) && Left.TokenText.endswith("${")) ||
2927         (Right.is(TT_TemplateString) && Right.TokenText.startswith("}")))
2928       return 100;
2929     // Prefer breaking call chains (".foo") over empty "{}", "[]" or "()".
2930     if (Left.opensScope() && Right.closesScope())
2931       return 200;
2932   }
2933 
2934   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
2935     return 1;
2936   if (Right.is(tok::l_square)) {
2937     if (Style.Language == FormatStyle::LK_Proto)
2938       return 1;
2939     if (Left.is(tok::r_square))
2940       return 200;
2941     // Slightly prefer formatting local lambda definitions like functions.
2942     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
2943       return 35;
2944     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
2945                        TT_ArrayInitializerLSquare,
2946                        TT_DesignatedInitializerLSquare, TT_AttributeSquare))
2947       return 500;
2948   }
2949 
2950   if (Left.is(tok::coloncolon) ||
2951       (Right.is(tok::period) && Style.Language == FormatStyle::LK_Proto))
2952     return 500;
2953   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
2954       Right.is(tok::kw_operator)) {
2955     if (Line.startsWith(tok::kw_for) && Right.PartOfMultiVariableDeclStmt)
2956       return 3;
2957     if (Left.is(TT_StartOfName))
2958       return 110;
2959     if (InFunctionDecl && Right.NestingLevel == 0)
2960       return Style.PenaltyReturnTypeOnItsOwnLine;
2961     return 200;
2962   }
2963   if (Right.is(TT_PointerOrReference))
2964     return 190;
2965   if (Right.is(TT_LambdaArrow))
2966     return 110;
2967   if (Left.is(tok::equal) && Right.is(tok::l_brace))
2968     return 160;
2969   if (Left.is(TT_CastRParen))
2970     return 100;
2971   if (Left.isOneOf(tok::kw_class, tok::kw_struct))
2972     return 5000;
2973   if (Left.is(tok::comment))
2974     return 1000;
2975 
2976   if (Left.isOneOf(TT_RangeBasedForLoopColon, TT_InheritanceColon,
2977                    TT_CtorInitializerColon))
2978     return 2;
2979 
2980   if (Right.isMemberAccess()) {
2981     // Breaking before the "./->" of a chained call/member access is reasonably
2982     // cheap, as formatting those with one call per line is generally
2983     // desirable. In particular, it should be cheaper to break before the call
2984     // than it is to break inside a call's parameters, which could lead to weird
2985     // "hanging" indents. The exception is the very last "./->" to support this
2986     // frequent pattern:
2987     //
2988     //   aaaaaaaa.aaaaaaaa.bbbbbbb().ccccccccccccccccccccc(
2989     //       dddddddd);
2990     //
2991     // which might otherwise be blown up onto many lines. Here, clang-format
2992     // won't produce "hanging" indents anyway as there is no other trailing
2993     // call.
2994     //
2995     // Also apply higher penalty is not a call as that might lead to a wrapping
2996     // like:
2997     //
2998     //   aaaaaaa
2999     //       .aaaaaaaaa.bbbbbbbb(cccccccc);
3000     return !Right.NextOperator || !Right.NextOperator->Previous->closesScope()
3001                ? 150
3002                : 35;
3003   }
3004 
3005   if (Right.is(TT_TrailingAnnotation) &&
3006       (!Right.Next || Right.Next->isNot(tok::l_paren))) {
3007     // Moving trailing annotations to the next line is fine for ObjC method
3008     // declarations.
3009     if (Line.startsWith(TT_ObjCMethodSpecifier))
3010       return 10;
3011     // Generally, breaking before a trailing annotation is bad unless it is
3012     // function-like. It seems to be especially preferable to keep standard
3013     // annotations (i.e. "const", "final" and "override") on the same line.
3014     // Use a slightly higher penalty after ")" so that annotations like
3015     // "const override" are kept together.
3016     bool is_short_annotation = Right.TokenText.size() < 10;
3017     return (Left.is(tok::r_paren) ? 100 : 120) + (is_short_annotation ? 50 : 0);
3018   }
3019 
3020   // In for-loops, prefer breaking at ',' and ';'.
3021   if (Line.startsWith(tok::kw_for) && Left.is(tok::equal))
3022     return 4;
3023 
3024   // In Objective-C method expressions, prefer breaking before "param:" over
3025   // breaking after it.
3026   if (Right.is(TT_SelectorName))
3027     return 0;
3028   if (Left.is(tok::colon) && Left.is(TT_ObjCMethodExpr))
3029     return Line.MightBeFunctionDecl ? 50 : 500;
3030 
3031   // In Objective-C type declarations, avoid breaking after the category's
3032   // open paren (we'll prefer breaking after the protocol list's opening
3033   // angle bracket, if present).
3034   if (Line.Type == LT_ObjCDecl && Left.is(tok::l_paren) && Left.Previous &&
3035       Left.Previous->isOneOf(tok::identifier, tok::greater))
3036     return 500;
3037 
3038   if (Left.is(tok::l_paren) && Style.PenaltyBreakOpenParenthesis != 0)
3039     return Style.PenaltyBreakOpenParenthesis;
3040   if (Left.is(tok::l_paren) && InFunctionDecl &&
3041       Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign)
3042     return 100;
3043   if (Left.is(tok::l_paren) && Left.Previous &&
3044       (Left.Previous->is(tok::kw_for) || Left.Previous->isIf()))
3045     return 1000;
3046   if (Left.is(tok::equal) && InFunctionDecl)
3047     return 110;
3048   if (Right.is(tok::r_brace))
3049     return 1;
3050   if (Left.is(TT_TemplateOpener))
3051     return 100;
3052   if (Left.opensScope()) {
3053     // If we aren't aligning after opening parens/braces we can always break
3054     // here unless the style does not want us to place all arguments on the
3055     // next line.
3056     if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign &&
3057         (Left.ParameterCount <= 1 || Style.AllowAllArgumentsOnNextLine))
3058       return 0;
3059     if (Left.is(tok::l_brace) && !Style.Cpp11BracedListStyle)
3060       return 19;
3061     return Left.ParameterCount > 1 ? Style.PenaltyBreakBeforeFirstCallParameter
3062                                    : 19;
3063   }
3064   if (Left.is(TT_JavaAnnotation))
3065     return 50;
3066 
3067   if (Left.is(TT_UnaryOperator))
3068     return 60;
3069   if (Left.isOneOf(tok::plus, tok::comma) && Left.Previous &&
3070       Left.Previous->isLabelString() &&
3071       (Left.NextOperator || Left.OperatorIndex != 0))
3072     return 50;
3073   if (Right.is(tok::plus) && Left.isLabelString() &&
3074       (Right.NextOperator || Right.OperatorIndex != 0))
3075     return 25;
3076   if (Left.is(tok::comma))
3077     return 1;
3078   if (Right.is(tok::lessless) && Left.isLabelString() &&
3079       (Right.NextOperator || Right.OperatorIndex != 1))
3080     return 25;
3081   if (Right.is(tok::lessless)) {
3082     // Breaking at a << is really cheap.
3083     if (!Left.is(tok::r_paren) || Right.OperatorIndex > 0)
3084       // Slightly prefer to break before the first one in log-like statements.
3085       return 2;
3086     return 1;
3087   }
3088   if (Left.ClosesTemplateDeclaration)
3089     return Style.PenaltyBreakTemplateDeclaration;
3090   if (Left.ClosesRequiresClause)
3091     return 0;
3092   if (Left.is(TT_ConditionalExpr))
3093     return prec::Conditional;
3094   prec::Level Level = Left.getPrecedence();
3095   if (Level == prec::Unknown)
3096     Level = Right.getPrecedence();
3097   if (Level == prec::Assignment)
3098     return Style.PenaltyBreakAssignment;
3099   if (Level != prec::Unknown)
3100     return Level;
3101 
3102   return 3;
3103 }
3104 
3105 bool TokenAnnotator::spaceRequiredBeforeParens(const FormatToken &Right) const {
3106   if (Style.SpaceBeforeParens == FormatStyle::SBPO_Always)
3107     return true;
3108   if (Right.is(TT_OverloadedOperatorLParen) &&
3109       Style.SpaceBeforeParensOptions.AfterOverloadedOperator)
3110     return true;
3111   if (Style.SpaceBeforeParensOptions.BeforeNonEmptyParentheses &&
3112       Right.ParameterCount > 0)
3113     return true;
3114   return false;
3115 }
3116 
3117 bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
3118                                           const FormatToken &Left,
3119                                           const FormatToken &Right) const {
3120   if (Left.is(tok::kw_return) &&
3121       !Right.isOneOf(tok::semi, tok::r_paren, tok::hashhash))
3122     return true;
3123   if (Style.isJson() && Left.is(tok::string_literal) && Right.is(tok::colon))
3124     return false;
3125   if (Left.is(Keywords.kw_assert) && Style.Language == FormatStyle::LK_Java)
3126     return true;
3127   if (Style.ObjCSpaceAfterProperty && Line.Type == LT_ObjCProperty &&
3128       Left.Tok.getObjCKeywordID() == tok::objc_property)
3129     return true;
3130   if (Right.is(tok::hashhash))
3131     return Left.is(tok::hash);
3132   if (Left.isOneOf(tok::hashhash, tok::hash))
3133     return Right.is(tok::hash);
3134   if ((Left.is(tok::l_paren) && Right.is(tok::r_paren)) ||
3135       (Left.is(tok::l_brace) && Left.isNot(BK_Block) &&
3136        Right.is(tok::r_brace) && Right.isNot(BK_Block)))
3137     return Style.SpaceInEmptyParentheses;
3138   if (Style.SpacesInConditionalStatement) {
3139     const FormatToken *LeftParen = nullptr;
3140     if (Left.is(tok::l_paren))
3141       LeftParen = &Left;
3142     else if (Right.is(tok::r_paren) && Right.MatchingParen)
3143       LeftParen = Right.MatchingParen;
3144     if (LeftParen && LeftParen->Previous &&
3145         isKeywordWithCondition(*LeftParen->Previous))
3146       return true;
3147   }
3148 
3149   // auto{x} auto(x)
3150   if (Left.is(tok::kw_auto) && Right.isOneOf(tok::l_paren, tok::l_brace))
3151     return false;
3152 
3153   // operator co_await(x)
3154   if (Right.is(tok::l_paren) && Left.is(tok::kw_co_await) && Left.Previous &&
3155       Left.Previous->is(tok::kw_operator))
3156     return false;
3157   // co_await (x), co_yield (x), co_return (x)
3158   if (Left.isOneOf(tok::kw_co_await, tok::kw_co_yield, tok::kw_co_return) &&
3159       !Right.isOneOf(tok::semi, tok::r_paren))
3160     return true;
3161 
3162   if (Left.is(tok::l_paren) || Right.is(tok::r_paren))
3163     return (Right.is(TT_CastRParen) ||
3164             (Left.MatchingParen && Left.MatchingParen->is(TT_CastRParen)))
3165                ? Style.SpacesInCStyleCastParentheses
3166                : Style.SpacesInParentheses;
3167   if (Right.isOneOf(tok::semi, tok::comma))
3168     return false;
3169   if (Right.is(tok::less) && Line.Type == LT_ObjCDecl) {
3170     bool IsLightweightGeneric = Right.MatchingParen &&
3171                                 Right.MatchingParen->Next &&
3172                                 Right.MatchingParen->Next->is(tok::colon);
3173     return !IsLightweightGeneric && Style.ObjCSpaceBeforeProtocolList;
3174   }
3175   if (Right.is(tok::less) && Left.is(tok::kw_template))
3176     return Style.SpaceAfterTemplateKeyword;
3177   if (Left.isOneOf(tok::exclaim, tok::tilde))
3178     return false;
3179   if (Left.is(tok::at) &&
3180       Right.isOneOf(tok::identifier, tok::string_literal, tok::char_constant,
3181                     tok::numeric_constant, tok::l_paren, tok::l_brace,
3182                     tok::kw_true, tok::kw_false))
3183     return false;
3184   if (Left.is(tok::colon))
3185     return !Left.is(TT_ObjCMethodExpr);
3186   if (Left.is(tok::coloncolon))
3187     return false;
3188   if (Left.is(tok::less) || Right.isOneOf(tok::greater, tok::less)) {
3189     if (Style.Language == FormatStyle::LK_TextProto ||
3190         (Style.Language == FormatStyle::LK_Proto &&
3191          (Left.is(TT_DictLiteral) || Right.is(TT_DictLiteral)))) {
3192       // Format empty list as `<>`.
3193       if (Left.is(tok::less) && Right.is(tok::greater))
3194         return false;
3195       return !Style.Cpp11BracedListStyle;
3196     }
3197     return false;
3198   }
3199   if (Right.is(tok::ellipsis))
3200     return Left.Tok.isLiteral() || (Left.is(tok::identifier) && Left.Previous &&
3201                                     Left.Previous->is(tok::kw_case));
3202   if (Left.is(tok::l_square) && Right.is(tok::amp))
3203     return Style.SpacesInSquareBrackets;
3204   if (Right.is(TT_PointerOrReference)) {
3205     if (Left.is(tok::r_paren) && Line.MightBeFunctionDecl) {
3206       if (!Left.MatchingParen)
3207         return true;
3208       FormatToken *TokenBeforeMatchingParen =
3209           Left.MatchingParen->getPreviousNonComment();
3210       if (!TokenBeforeMatchingParen || !Left.is(TT_TypeDeclarationParen))
3211         return true;
3212     }
3213     // Add a space if the previous token is a pointer qualifier or the closing
3214     // parenthesis of __attribute__(()) expression and the style requires spaces
3215     // after pointer qualifiers.
3216     if ((Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_After ||
3217          Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Both) &&
3218         (Left.is(TT_AttributeParen) || Left.canBePointerOrReferenceQualifier()))
3219       return true;
3220     if (Left.Tok.isLiteral())
3221       return true;
3222     // for (auto a = 0, b = 0; const auto & c : {1, 2, 3})
3223     if (Left.isTypeOrIdentifier() && Right.Next && Right.Next->Next &&
3224         Right.Next->Next->is(TT_RangeBasedForLoopColon))
3225       return getTokenPointerOrReferenceAlignment(Right) !=
3226              FormatStyle::PAS_Left;
3227     return !Left.isOneOf(TT_PointerOrReference, tok::l_paren) &&
3228            (getTokenPointerOrReferenceAlignment(Right) !=
3229                 FormatStyle::PAS_Left ||
3230             (Line.IsMultiVariableDeclStmt &&
3231              (Left.NestingLevel == 0 ||
3232               (Left.NestingLevel == 1 && startsWithInitStatement(Line)))));
3233   }
3234   if (Right.is(TT_FunctionTypeLParen) && Left.isNot(tok::l_paren) &&
3235       (!Left.is(TT_PointerOrReference) ||
3236        (getTokenPointerOrReferenceAlignment(Left) != FormatStyle::PAS_Right &&
3237         !Line.IsMultiVariableDeclStmt)))
3238     return true;
3239   if (Left.is(TT_PointerOrReference)) {
3240     // Add a space if the next token is a pointer qualifier and the style
3241     // requires spaces before pointer qualifiers.
3242     if ((Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Before ||
3243          Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Both) &&
3244         Right.canBePointerOrReferenceQualifier())
3245       return true;
3246     // & 1
3247     if (Right.Tok.isLiteral())
3248       return true;
3249     // & /* comment
3250     if (Right.is(TT_BlockComment))
3251       return true;
3252     // foo() -> const Bar * override/final
3253     if (Right.isOneOf(Keywords.kw_override, Keywords.kw_final) &&
3254         !Right.is(TT_StartOfName))
3255       return true;
3256     // & {
3257     if (Right.is(tok::l_brace) && Right.is(BK_Block))
3258       return true;
3259     // for (auto a = 0, b = 0; const auto& c : {1, 2, 3})
3260     if (Left.Previous && Left.Previous->isTypeOrIdentifier() && Right.Next &&
3261         Right.Next->is(TT_RangeBasedForLoopColon))
3262       return getTokenPointerOrReferenceAlignment(Left) !=
3263              FormatStyle::PAS_Right;
3264     if (Right.isOneOf(TT_PointerOrReference, TT_ArraySubscriptLSquare,
3265                       tok::l_paren))
3266       return false;
3267     if (getTokenPointerOrReferenceAlignment(Left) == FormatStyle::PAS_Right)
3268       return false;
3269     // FIXME: Setting IsMultiVariableDeclStmt for the whole line is error-prone,
3270     // because it does not take into account nested scopes like lambdas.
3271     // In multi-variable declaration statements, attach */& to the variable
3272     // independently of the style. However, avoid doing it if we are in a nested
3273     // scope, e.g. lambda. We still need to special-case statements with
3274     // initializers.
3275     if (Line.IsMultiVariableDeclStmt &&
3276         (Left.NestingLevel == Line.First->NestingLevel ||
3277          ((Left.NestingLevel == Line.First->NestingLevel + 1) &&
3278           startsWithInitStatement(Line))))
3279       return false;
3280     return Left.Previous && !Left.Previous->isOneOf(
3281                                 tok::l_paren, tok::coloncolon, tok::l_square);
3282   }
3283   // Ensure right pointer alignment with ellipsis e.g. int *...P
3284   if (Left.is(tok::ellipsis) && Left.Previous &&
3285       Left.Previous->isOneOf(tok::star, tok::amp, tok::ampamp))
3286     return Style.PointerAlignment != FormatStyle::PAS_Right;
3287 
3288   if (Right.is(tok::star) && Left.is(tok::l_paren))
3289     return false;
3290   if (Left.is(tok::star) && Right.isOneOf(tok::star, tok::amp, tok::ampamp))
3291     return false;
3292   if (Right.isOneOf(tok::star, tok::amp, tok::ampamp)) {
3293     const FormatToken *Previous = &Left;
3294     while (Previous && !Previous->is(tok::kw_operator)) {
3295       if (Previous->is(tok::identifier) || Previous->isSimpleTypeSpecifier()) {
3296         Previous = Previous->getPreviousNonComment();
3297         continue;
3298       }
3299       if (Previous->is(TT_TemplateCloser) && Previous->MatchingParen) {
3300         Previous = Previous->MatchingParen->getPreviousNonComment();
3301         continue;
3302       }
3303       if (Previous->is(tok::coloncolon)) {
3304         Previous = Previous->getPreviousNonComment();
3305         continue;
3306       }
3307       break;
3308     }
3309     // Space between the type and the * in:
3310     //   operator void*()
3311     //   operator char*()
3312     //   operator void const*()
3313     //   operator void volatile*()
3314     //   operator /*comment*/ const char*()
3315     //   operator volatile /*comment*/ char*()
3316     //   operator Foo*()
3317     //   operator C<T>*()
3318     //   operator std::Foo*()
3319     //   operator C<T>::D<U>*()
3320     // dependent on PointerAlignment style.
3321     if (Previous) {
3322       if (Previous->endsSequence(tok::kw_operator))
3323         return Style.PointerAlignment != FormatStyle::PAS_Left;
3324       if (Previous->is(tok::kw_const) || Previous->is(tok::kw_volatile))
3325         return (Style.PointerAlignment != FormatStyle::PAS_Left) ||
3326                (Style.SpaceAroundPointerQualifiers ==
3327                 FormatStyle::SAPQ_After) ||
3328                (Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Both);
3329     }
3330   }
3331   const auto SpaceRequiredForArrayInitializerLSquare =
3332       [](const FormatToken &LSquareTok, const FormatStyle &Style) {
3333         return Style.SpacesInContainerLiterals ||
3334                ((Style.Language == FormatStyle::LK_Proto ||
3335                  Style.Language == FormatStyle::LK_TextProto) &&
3336                 !Style.Cpp11BracedListStyle &&
3337                 LSquareTok.endsSequence(tok::l_square, tok::colon,
3338                                         TT_SelectorName));
3339       };
3340   if (Left.is(tok::l_square))
3341     return (Left.is(TT_ArrayInitializerLSquare) && Right.isNot(tok::r_square) &&
3342             SpaceRequiredForArrayInitializerLSquare(Left, Style)) ||
3343            (Left.isOneOf(TT_ArraySubscriptLSquare, TT_StructuredBindingLSquare,
3344                          TT_LambdaLSquare) &&
3345             Style.SpacesInSquareBrackets && Right.isNot(tok::r_square));
3346   if (Right.is(tok::r_square))
3347     return Right.MatchingParen &&
3348            ((Right.MatchingParen->is(TT_ArrayInitializerLSquare) &&
3349              SpaceRequiredForArrayInitializerLSquare(*Right.MatchingParen,
3350                                                      Style)) ||
3351             (Style.SpacesInSquareBrackets &&
3352              Right.MatchingParen->isOneOf(TT_ArraySubscriptLSquare,
3353                                           TT_StructuredBindingLSquare,
3354                                           TT_LambdaLSquare)) ||
3355             Right.MatchingParen->is(TT_AttributeParen));
3356   if (Right.is(tok::l_square) &&
3357       !Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
3358                      TT_DesignatedInitializerLSquare,
3359                      TT_StructuredBindingLSquare, TT_AttributeSquare) &&
3360       !Left.isOneOf(tok::numeric_constant, TT_DictLiteral) &&
3361       !(!Left.is(tok::r_square) && Style.SpaceBeforeSquareBrackets &&
3362         Right.is(TT_ArraySubscriptLSquare)))
3363     return false;
3364   if (Left.is(tok::l_brace) && Right.is(tok::r_brace))
3365     return !Left.Children.empty(); // No spaces in "{}".
3366   if ((Left.is(tok::l_brace) && Left.isNot(BK_Block)) ||
3367       (Right.is(tok::r_brace) && Right.MatchingParen &&
3368        Right.MatchingParen->isNot(BK_Block)))
3369     return Style.Cpp11BracedListStyle ? Style.SpacesInParentheses : true;
3370   if (Left.is(TT_BlockComment))
3371     // No whitespace in x(/*foo=*/1), except for JavaScript.
3372     return Style.isJavaScript() || !Left.TokenText.endswith("=*/");
3373 
3374   // Space between template and attribute.
3375   // e.g. template <typename T> [[nodiscard]] ...
3376   if (Left.is(TT_TemplateCloser) && Right.is(TT_AttributeSquare))
3377     return true;
3378   // Space before parentheses common for all languages
3379   if (Right.is(tok::l_paren)) {
3380     if (Left.is(TT_TemplateCloser) && Right.isNot(TT_FunctionTypeLParen))
3381       return spaceRequiredBeforeParens(Right);
3382     if (Left.isOneOf(TT_RequiresClause, TT_RequiresClauseInARequiresExpression))
3383       return Style.SpaceBeforeParensOptions.AfterRequiresInClause ||
3384              spaceRequiredBeforeParens(Right);
3385     if (Left.is(TT_RequiresExpression))
3386       return Style.SpaceBeforeParensOptions.AfterRequiresInExpression ||
3387              spaceRequiredBeforeParens(Right);
3388     if ((Left.is(tok::r_paren) && Left.is(TT_AttributeParen)) ||
3389         (Left.is(tok::r_square) && Left.is(TT_AttributeSquare)))
3390       return true;
3391     if (Left.is(TT_ForEachMacro))
3392       return Style.SpaceBeforeParensOptions.AfterForeachMacros ||
3393              spaceRequiredBeforeParens(Right);
3394     if (Left.is(TT_IfMacro))
3395       return Style.SpaceBeforeParensOptions.AfterIfMacros ||
3396              spaceRequiredBeforeParens(Right);
3397     if (Line.Type == LT_ObjCDecl)
3398       return true;
3399     if (Left.is(tok::semi))
3400       return true;
3401     if (Left.isOneOf(tok::pp_elif, tok::kw_for, tok::kw_while, tok::kw_switch,
3402                      tok::kw_case, TT_ForEachMacro, TT_ObjCForIn) ||
3403         Left.isIf(Line.Type != LT_PreprocessorDirective))
3404       return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3405              spaceRequiredBeforeParens(Right);
3406 
3407     // TODO add Operator overloading specific Options to
3408     // SpaceBeforeParensOptions
3409     if (Right.is(TT_OverloadedOperatorLParen))
3410       return spaceRequiredBeforeParens(Right);
3411     // Function declaration or definition
3412     if (Line.MightBeFunctionDecl && (Left.is(TT_FunctionDeclarationName))) {
3413       if (Line.mightBeFunctionDefinition())
3414         return Style.SpaceBeforeParensOptions.AfterFunctionDefinitionName ||
3415                spaceRequiredBeforeParens(Right);
3416       else
3417         return Style.SpaceBeforeParensOptions.AfterFunctionDeclarationName ||
3418                spaceRequiredBeforeParens(Right);
3419     }
3420     // Lambda
3421     if (Line.Type != LT_PreprocessorDirective && Left.is(tok::r_square) &&
3422         Left.MatchingParen && Left.MatchingParen->is(TT_LambdaLSquare))
3423       return Style.SpaceBeforeParensOptions.AfterFunctionDefinitionName ||
3424              spaceRequiredBeforeParens(Right);
3425     if (!Left.Previous || Left.Previous->isNot(tok::period)) {
3426       if (Left.isOneOf(tok::kw_try, Keywords.kw___except, tok::kw_catch))
3427         return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3428                spaceRequiredBeforeParens(Right);
3429       if (Left.isOneOf(tok::kw_new, tok::kw_delete))
3430         return ((!Line.MightBeFunctionDecl || !Left.Previous) &&
3431                 Style.SpaceBeforeParens != FormatStyle::SBPO_Never) ||
3432                spaceRequiredBeforeParens(Right);
3433 
3434       if (Left.is(tok::r_square) && Left.MatchingParen &&
3435           Left.MatchingParen->Previous &&
3436           Left.MatchingParen->Previous->is(tok::kw_delete))
3437         return (Style.SpaceBeforeParens != FormatStyle::SBPO_Never) ||
3438                spaceRequiredBeforeParens(Right);
3439     }
3440     // Handle builtins like identifiers.
3441     if (Line.Type != LT_PreprocessorDirective &&
3442         (Left.Tok.getIdentifierInfo() || Left.is(tok::r_paren)))
3443       return spaceRequiredBeforeParens(Right);
3444     return false;
3445   }
3446   if (Left.is(tok::at) && Right.Tok.getObjCKeywordID() != tok::objc_not_keyword)
3447     return false;
3448   if (Right.is(TT_UnaryOperator))
3449     return !Left.isOneOf(tok::l_paren, tok::l_square, tok::at) &&
3450            (Left.isNot(tok::colon) || Left.isNot(TT_ObjCMethodExpr));
3451   if ((Left.isOneOf(tok::identifier, tok::greater, tok::r_square,
3452                     tok::r_paren) ||
3453        Left.isSimpleTypeSpecifier()) &&
3454       Right.is(tok::l_brace) && Right.getNextNonComment() &&
3455       Right.isNot(BK_Block))
3456     return false;
3457   if (Left.is(tok::period) || Right.is(tok::period))
3458     return false;
3459   // u#str, U#str, L#str, u8#str
3460   // uR#str, UR#str, LR#str, u8R#str
3461   if (Right.is(tok::hash) && Left.is(tok::identifier) &&
3462       (Left.TokenText == "L" || Left.TokenText == "u" ||
3463        Left.TokenText == "U" || Left.TokenText == "u8" ||
3464        Left.TokenText == "LR" || Left.TokenText == "uR" ||
3465        Left.TokenText == "UR" || Left.TokenText == "u8R"))
3466     return false;
3467   if (Left.is(TT_TemplateCloser) && Left.MatchingParen &&
3468       Left.MatchingParen->Previous &&
3469       (Left.MatchingParen->Previous->is(tok::period) ||
3470        Left.MatchingParen->Previous->is(tok::coloncolon)))
3471     // Java call to generic function with explicit type:
3472     // A.<B<C<...>>>DoSomething();
3473     // A::<B<C<...>>>DoSomething();  // With a Java 8 method reference.
3474     return false;
3475   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_square))
3476     return false;
3477   if (Left.is(tok::l_brace) && Left.endsSequence(TT_DictLiteral, tok::at))
3478     // Objective-C dictionary literal -> no space after opening brace.
3479     return false;
3480   if (Right.is(tok::r_brace) && Right.MatchingParen &&
3481       Right.MatchingParen->endsSequence(TT_DictLiteral, tok::at))
3482     // Objective-C dictionary literal -> no space before closing brace.
3483     return false;
3484   if (Right.getType() == TT_TrailingAnnotation &&
3485       Right.isOneOf(tok::amp, tok::ampamp) &&
3486       Left.isOneOf(tok::kw_const, tok::kw_volatile) &&
3487       (!Right.Next || Right.Next->is(tok::semi)))
3488     // Match const and volatile ref-qualifiers without any additional
3489     // qualifiers such as
3490     // void Fn() const &;
3491     return getTokenReferenceAlignment(Right) != FormatStyle::PAS_Left;
3492 
3493   return true;
3494 }
3495 
3496 bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
3497                                          const FormatToken &Right) const {
3498   const FormatToken &Left = *Right.Previous;
3499 
3500   // If the token is finalized don't touch it (as it could be in a
3501   // clang-format-off section).
3502   if (Left.Finalized)
3503     return Right.hasWhitespaceBefore();
3504 
3505   if (Right.Tok.getIdentifierInfo() && Left.Tok.getIdentifierInfo())
3506     return true; // Never ever merge two identifiers.
3507 
3508   // Leave a space between * and /* to avoid C4138 `comment end` found outside
3509   // of comment.
3510   if (Left.is(tok::star) && Right.is(tok::comment))
3511     return true;
3512 
3513   if (Style.isCpp()) {
3514     // Space between import <iostream>.
3515     // or import .....;
3516     if (Left.is(Keywords.kw_import) && Right.isOneOf(tok::less, tok::ellipsis))
3517       return true;
3518     // Space between `module :` and `import :`.
3519     if (Left.isOneOf(Keywords.kw_module, Keywords.kw_import) &&
3520         Right.is(TT_ModulePartitionColon))
3521       return true;
3522     // No space between import foo:bar but keep a space between import :bar;
3523     if (Left.is(tok::identifier) && Right.is(TT_ModulePartitionColon))
3524       return false;
3525     // No space between :bar;
3526     if (Left.is(TT_ModulePartitionColon) &&
3527         Right.isOneOf(tok::identifier, tok::kw_private))
3528       return false;
3529     if (Left.is(tok::ellipsis) && Right.is(tok::identifier) &&
3530         Line.First->is(Keywords.kw_import))
3531       return false;
3532     // Space in __attribute__((attr)) ::type.
3533     if (Left.is(TT_AttributeParen) && Right.is(tok::coloncolon))
3534       return true;
3535 
3536     if (Left.is(tok::kw_operator))
3537       return Right.is(tok::coloncolon);
3538     if (Right.is(tok::l_brace) && Right.is(BK_BracedInit) &&
3539         !Left.opensScope() && Style.SpaceBeforeCpp11BracedList)
3540       return true;
3541     if (Left.is(tok::less) && Left.is(TT_OverloadedOperator) &&
3542         Right.is(TT_TemplateOpener))
3543       return true;
3544   } else if (Style.Language == FormatStyle::LK_Proto ||
3545              Style.Language == FormatStyle::LK_TextProto) {
3546     if (Right.is(tok::period) &&
3547         Left.isOneOf(Keywords.kw_optional, Keywords.kw_required,
3548                      Keywords.kw_repeated, Keywords.kw_extend))
3549       return true;
3550     if (Right.is(tok::l_paren) &&
3551         Left.isOneOf(Keywords.kw_returns, Keywords.kw_option))
3552       return true;
3553     if (Right.isOneOf(tok::l_brace, tok::less) && Left.is(TT_SelectorName))
3554       return true;
3555     // Slashes occur in text protocol extension syntax: [type/type] { ... }.
3556     if (Left.is(tok::slash) || Right.is(tok::slash))
3557       return false;
3558     if (Left.MatchingParen &&
3559         Left.MatchingParen->is(TT_ProtoExtensionLSquare) &&
3560         Right.isOneOf(tok::l_brace, tok::less))
3561       return !Style.Cpp11BracedListStyle;
3562     // A percent is probably part of a formatting specification, such as %lld.
3563     if (Left.is(tok::percent))
3564       return false;
3565     // Preserve the existence of a space before a percent for cases like 0x%04x
3566     // and "%d %d"
3567     if (Left.is(tok::numeric_constant) && Right.is(tok::percent))
3568       return Right.hasWhitespaceBefore();
3569   } else if (Style.isJson()) {
3570     if (Right.is(tok::colon))
3571       return false;
3572   } else if (Style.isCSharp()) {
3573     // Require spaces around '{' and  before '}' unless they appear in
3574     // interpolated strings. Interpolated strings are merged into a single token
3575     // so cannot have spaces inserted by this function.
3576 
3577     // No space between 'this' and '['
3578     if (Left.is(tok::kw_this) && Right.is(tok::l_square))
3579       return false;
3580 
3581     // No space between 'new' and '('
3582     if (Left.is(tok::kw_new) && Right.is(tok::l_paren))
3583       return false;
3584 
3585     // Space before { (including space within '{ {').
3586     if (Right.is(tok::l_brace))
3587       return true;
3588 
3589     // Spaces inside braces.
3590     if (Left.is(tok::l_brace) && Right.isNot(tok::r_brace))
3591       return true;
3592 
3593     if (Left.isNot(tok::l_brace) && Right.is(tok::r_brace))
3594       return true;
3595 
3596     // Spaces around '=>'.
3597     if (Left.is(TT_FatArrow) || Right.is(TT_FatArrow))
3598       return true;
3599 
3600     // No spaces around attribute target colons
3601     if (Left.is(TT_AttributeColon) || Right.is(TT_AttributeColon))
3602       return false;
3603 
3604     // space between type and variable e.g. Dictionary<string,string> foo;
3605     if (Left.is(TT_TemplateCloser) && Right.is(TT_StartOfName))
3606       return true;
3607 
3608     // spaces inside square brackets.
3609     if (Left.is(tok::l_square) || Right.is(tok::r_square))
3610       return Style.SpacesInSquareBrackets;
3611 
3612     // No space before ? in nullable types.
3613     if (Right.is(TT_CSharpNullable))
3614       return false;
3615 
3616     // No space before null forgiving '!'.
3617     if (Right.is(TT_NonNullAssertion))
3618       return false;
3619 
3620     // No space between consecutive commas '[,,]'.
3621     if (Left.is(tok::comma) && Right.is(tok::comma))
3622       return false;
3623 
3624     // space after var in `var (key, value)`
3625     if (Left.is(Keywords.kw_var) && Right.is(tok::l_paren))
3626       return true;
3627 
3628     // space between keywords and paren e.g. "using ("
3629     if (Right.is(tok::l_paren))
3630       if (Left.isOneOf(tok::kw_using, Keywords.kw_async, Keywords.kw_when,
3631                        Keywords.kw_lock))
3632         return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3633                spaceRequiredBeforeParens(Right);
3634 
3635     // space between method modifier and opening parenthesis of a tuple return
3636     // type
3637     if (Left.isOneOf(tok::kw_public, tok::kw_private, tok::kw_protected,
3638                      tok::kw_virtual, tok::kw_extern, tok::kw_static,
3639                      Keywords.kw_internal, Keywords.kw_abstract,
3640                      Keywords.kw_sealed, Keywords.kw_override,
3641                      Keywords.kw_async, Keywords.kw_unsafe) &&
3642         Right.is(tok::l_paren))
3643       return true;
3644   } else if (Style.isJavaScript()) {
3645     if (Left.is(TT_FatArrow))
3646       return true;
3647     // for await ( ...
3648     if (Right.is(tok::l_paren) && Left.is(Keywords.kw_await) && Left.Previous &&
3649         Left.Previous->is(tok::kw_for))
3650       return true;
3651     if (Left.is(Keywords.kw_async) && Right.is(tok::l_paren) &&
3652         Right.MatchingParen) {
3653       const FormatToken *Next = Right.MatchingParen->getNextNonComment();
3654       // An async arrow function, for example: `x = async () => foo();`,
3655       // as opposed to calling a function called async: `x = async();`
3656       if (Next && Next->is(TT_FatArrow))
3657         return true;
3658     }
3659     if ((Left.is(TT_TemplateString) && Left.TokenText.endswith("${")) ||
3660         (Right.is(TT_TemplateString) && Right.TokenText.startswith("}")))
3661       return false;
3662     // In tagged template literals ("html`bar baz`"), there is no space between
3663     // the tag identifier and the template string.
3664     if (Keywords.IsJavaScriptIdentifier(Left,
3665                                         /* AcceptIdentifierName= */ false) &&
3666         Right.is(TT_TemplateString))
3667       return false;
3668     if (Right.is(tok::star) &&
3669         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield))
3670       return false;
3671     if (Right.isOneOf(tok::l_brace, tok::l_square) &&
3672         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield,
3673                      Keywords.kw_extends, Keywords.kw_implements))
3674       return true;
3675     if (Right.is(tok::l_paren)) {
3676       // JS methods can use some keywords as names (e.g. `delete()`).
3677       if (Line.MustBeDeclaration && Left.Tok.getIdentifierInfo())
3678         return false;
3679       // Valid JS method names can include keywords, e.g. `foo.delete()` or
3680       // `bar.instanceof()`. Recognize call positions by preceding period.
3681       if (Left.Previous && Left.Previous->is(tok::period) &&
3682           Left.Tok.getIdentifierInfo())
3683         return false;
3684       // Additional unary JavaScript operators that need a space after.
3685       if (Left.isOneOf(tok::kw_throw, Keywords.kw_await, Keywords.kw_typeof,
3686                        tok::kw_void))
3687         return true;
3688     }
3689     // `foo as const;` casts into a const type.
3690     if (Left.endsSequence(tok::kw_const, Keywords.kw_as))
3691       return false;
3692     if ((Left.isOneOf(Keywords.kw_let, Keywords.kw_var, Keywords.kw_in,
3693                       tok::kw_const) ||
3694          // "of" is only a keyword if it appears after another identifier
3695          // (e.g. as "const x of y" in a for loop), or after a destructuring
3696          // operation (const [x, y] of z, const {a, b} of c).
3697          (Left.is(Keywords.kw_of) && Left.Previous &&
3698           (Left.Previous->is(tok::identifier) ||
3699            Left.Previous->isOneOf(tok::r_square, tok::r_brace)))) &&
3700         (!Left.Previous || !Left.Previous->is(tok::period)))
3701       return true;
3702     if (Left.isOneOf(tok::kw_for, Keywords.kw_as) && Left.Previous &&
3703         Left.Previous->is(tok::period) && Right.is(tok::l_paren))
3704       return false;
3705     if (Left.is(Keywords.kw_as) &&
3706         Right.isOneOf(tok::l_square, tok::l_brace, tok::l_paren))
3707       return true;
3708     if (Left.is(tok::kw_default) && Left.Previous &&
3709         Left.Previous->is(tok::kw_export))
3710       return true;
3711     if (Left.is(Keywords.kw_is) && Right.is(tok::l_brace))
3712       return true;
3713     if (Right.isOneOf(TT_JsTypeColon, TT_JsTypeOptionalQuestion))
3714       return false;
3715     if (Left.is(TT_JsTypeOperator) || Right.is(TT_JsTypeOperator))
3716       return false;
3717     if ((Left.is(tok::l_brace) || Right.is(tok::r_brace)) &&
3718         Line.First->isOneOf(Keywords.kw_import, tok::kw_export))
3719       return false;
3720     if (Left.is(tok::ellipsis))
3721       return false;
3722     if (Left.is(TT_TemplateCloser) &&
3723         !Right.isOneOf(tok::equal, tok::l_brace, tok::comma, tok::l_square,
3724                        Keywords.kw_implements, Keywords.kw_extends))
3725       // Type assertions ('<type>expr') are not followed by whitespace. Other
3726       // locations that should have whitespace following are identified by the
3727       // above set of follower tokens.
3728       return false;
3729     if (Right.is(TT_NonNullAssertion))
3730       return false;
3731     if (Left.is(TT_NonNullAssertion) &&
3732         Right.isOneOf(Keywords.kw_as, Keywords.kw_in))
3733       return true; // "x! as string", "x! in y"
3734   } else if (Style.Language == FormatStyle::LK_Java) {
3735     if (Left.is(tok::r_square) && Right.is(tok::l_brace))
3736       return true;
3737     if (Left.is(Keywords.kw_synchronized) && Right.is(tok::l_paren))
3738       return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3739              spaceRequiredBeforeParens(Right);
3740     if ((Left.isOneOf(tok::kw_static, tok::kw_public, tok::kw_private,
3741                       tok::kw_protected) ||
3742          Left.isOneOf(Keywords.kw_final, Keywords.kw_abstract,
3743                       Keywords.kw_native)) &&
3744         Right.is(TT_TemplateOpener))
3745       return true;
3746   }
3747   if (Left.is(TT_ImplicitStringLiteral))
3748     return Right.hasWhitespaceBefore();
3749   if (Line.Type == LT_ObjCMethodDecl) {
3750     if (Left.is(TT_ObjCMethodSpecifier))
3751       return true;
3752     if (Left.is(tok::r_paren) && canBeObjCSelectorComponent(Right))
3753       // Don't space between ')' and <id> or ')' and 'new'. 'new' is not a
3754       // keyword in Objective-C, and '+ (instancetype)new;' is a standard class
3755       // method declaration.
3756       return false;
3757   }
3758   if (Line.Type == LT_ObjCProperty &&
3759       (Right.is(tok::equal) || Left.is(tok::equal)))
3760     return false;
3761 
3762   if (Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow) ||
3763       Left.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow))
3764     return true;
3765   if (Left.is(tok::comma) && !Right.is(TT_OverloadedOperatorLParen))
3766     return true;
3767   if (Right.is(tok::comma))
3768     return false;
3769   if (Right.is(TT_ObjCBlockLParen))
3770     return true;
3771   if (Right.is(TT_CtorInitializerColon))
3772     return Style.SpaceBeforeCtorInitializerColon;
3773   if (Right.is(TT_InheritanceColon) && !Style.SpaceBeforeInheritanceColon)
3774     return false;
3775   if (Right.is(TT_RangeBasedForLoopColon) &&
3776       !Style.SpaceBeforeRangeBasedForLoopColon)
3777     return false;
3778   if (Left.is(TT_BitFieldColon))
3779     return Style.BitFieldColonSpacing == FormatStyle::BFCS_Both ||
3780            Style.BitFieldColonSpacing == FormatStyle::BFCS_After;
3781   if (Right.is(tok::colon)) {
3782     if (Line.First->isOneOf(tok::kw_default, tok::kw_case))
3783       return Style.SpaceBeforeCaseColon;
3784     const FormatToken *Next = Right.getNextNonComment();
3785     if (!Next || Next->is(tok::semi))
3786       return false;
3787     if (Right.is(TT_ObjCMethodExpr))
3788       return false;
3789     if (Left.is(tok::question))
3790       return false;
3791     if (Right.is(TT_InlineASMColon) && Left.is(tok::coloncolon))
3792       return false;
3793     if (Right.is(TT_DictLiteral))
3794       return Style.SpacesInContainerLiterals;
3795     if (Right.is(TT_AttributeColon))
3796       return false;
3797     if (Right.is(TT_CSharpNamedArgumentColon))
3798       return false;
3799     if (Right.is(TT_BitFieldColon))
3800       return Style.BitFieldColonSpacing == FormatStyle::BFCS_Both ||
3801              Style.BitFieldColonSpacing == FormatStyle::BFCS_Before;
3802     return true;
3803   }
3804   // Do not merge "- -" into "--".
3805   if ((Left.isOneOf(tok::minus, tok::minusminus) &&
3806        Right.isOneOf(tok::minus, tok::minusminus)) ||
3807       (Left.isOneOf(tok::plus, tok::plusplus) &&
3808        Right.isOneOf(tok::plus, tok::plusplus)))
3809     return true;
3810   if (Left.is(TT_UnaryOperator)) {
3811     if (!Right.is(tok::l_paren)) {
3812       // The alternative operators for ~ and ! are "compl" and "not".
3813       // If they are used instead, we do not want to combine them with
3814       // the token to the right, unless that is a left paren.
3815       if (Left.is(tok::exclaim) && Left.TokenText == "not")
3816         return true;
3817       if (Left.is(tok::tilde) && Left.TokenText == "compl")
3818         return true;
3819       // Lambda captures allow for a lone &, so "&]" needs to be properly
3820       // handled.
3821       if (Left.is(tok::amp) && Right.is(tok::r_square))
3822         return Style.SpacesInSquareBrackets;
3823     }
3824     return (Style.SpaceAfterLogicalNot && Left.is(tok::exclaim)) ||
3825            Right.is(TT_BinaryOperator);
3826   }
3827 
3828   // If the next token is a binary operator or a selector name, we have
3829   // incorrectly classified the parenthesis as a cast. FIXME: Detect correctly.
3830   if (Left.is(TT_CastRParen))
3831     return Style.SpaceAfterCStyleCast ||
3832            Right.isOneOf(TT_BinaryOperator, TT_SelectorName);
3833 
3834   auto ShouldAddSpacesInAngles = [this, &Right]() {
3835     if (this->Style.SpacesInAngles == FormatStyle::SIAS_Always)
3836       return true;
3837     if (this->Style.SpacesInAngles == FormatStyle::SIAS_Leave)
3838       return Right.hasWhitespaceBefore();
3839     return false;
3840   };
3841 
3842   if (Left.is(tok::greater) && Right.is(tok::greater)) {
3843     if (Style.Language == FormatStyle::LK_TextProto ||
3844         (Style.Language == FormatStyle::LK_Proto && Left.is(TT_DictLiteral)))
3845       return !Style.Cpp11BracedListStyle;
3846     return Right.is(TT_TemplateCloser) && Left.is(TT_TemplateCloser) &&
3847            ((Style.Standard < FormatStyle::LS_Cpp11) ||
3848             ShouldAddSpacesInAngles());
3849   }
3850   if (Right.isOneOf(tok::arrow, tok::arrowstar, tok::periodstar) ||
3851       Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
3852       (Right.is(tok::period) && Right.isNot(TT_DesignatedInitializerPeriod)))
3853     return false;
3854   if (!Style.SpaceBeforeAssignmentOperators && Left.isNot(TT_TemplateCloser) &&
3855       Right.getPrecedence() == prec::Assignment)
3856     return false;
3857   if (Style.Language == FormatStyle::LK_Java && Right.is(tok::coloncolon) &&
3858       (Left.is(tok::identifier) || Left.is(tok::kw_this)))
3859     return false;
3860   if (Right.is(tok::coloncolon) && Left.is(tok::identifier))
3861     // Generally don't remove existing spaces between an identifier and "::".
3862     // The identifier might actually be a macro name such as ALWAYS_INLINE. If
3863     // this turns out to be too lenient, add analysis of the identifier itself.
3864     return Right.hasWhitespaceBefore();
3865   if (Right.is(tok::coloncolon) &&
3866       !Left.isOneOf(tok::l_brace, tok::comment, tok::l_paren))
3867     // Put a space between < and :: in vector< ::std::string >
3868     return (Left.is(TT_TemplateOpener) &&
3869             ((Style.Standard < FormatStyle::LS_Cpp11) ||
3870              ShouldAddSpacesInAngles())) ||
3871            !(Left.isOneOf(tok::l_paren, tok::r_paren, tok::l_square,
3872                           tok::kw___super, TT_TemplateOpener,
3873                           TT_TemplateCloser)) ||
3874            (Left.is(tok::l_paren) && Style.SpacesInParentheses);
3875   if ((Left.is(TT_TemplateOpener)) != (Right.is(TT_TemplateCloser)))
3876     return ShouldAddSpacesInAngles();
3877   // Space before TT_StructuredBindingLSquare.
3878   if (Right.is(TT_StructuredBindingLSquare))
3879     return !Left.isOneOf(tok::amp, tok::ampamp) ||
3880            getTokenReferenceAlignment(Left) != FormatStyle::PAS_Right;
3881   // Space before & or && following a TT_StructuredBindingLSquare.
3882   if (Right.Next && Right.Next->is(TT_StructuredBindingLSquare) &&
3883       Right.isOneOf(tok::amp, tok::ampamp))
3884     return getTokenReferenceAlignment(Right) != FormatStyle::PAS_Left;
3885   if ((Right.is(TT_BinaryOperator) && !Left.is(tok::l_paren)) ||
3886       (Left.isOneOf(TT_BinaryOperator, TT_ConditionalExpr) &&
3887        !Right.is(tok::r_paren)))
3888     return true;
3889   if (Right.is(TT_TemplateOpener) && Left.is(tok::r_paren) &&
3890       Left.MatchingParen && Left.MatchingParen->is(TT_OverloadedOperatorLParen))
3891     return false;
3892   if (Right.is(tok::less) && Left.isNot(tok::l_paren) &&
3893       Line.startsWith(tok::hash))
3894     return true;
3895   if (Right.is(TT_TrailingUnaryOperator))
3896     return false;
3897   if (Left.is(TT_RegexLiteral))
3898     return false;
3899   return spaceRequiredBetween(Line, Left, Right);
3900 }
3901 
3902 // Returns 'true' if 'Tok' is a brace we'd want to break before in Allman style.
3903 static bool isAllmanBrace(const FormatToken &Tok) {
3904   return Tok.is(tok::l_brace) && Tok.is(BK_Block) &&
3905          !Tok.isOneOf(TT_ObjCBlockLBrace, TT_LambdaLBrace, TT_DictLiteral);
3906 }
3907 
3908 // Returns 'true' if 'Tok' is a function argument.
3909 static bool IsFunctionArgument(const FormatToken &Tok) {
3910   return Tok.MatchingParen && Tok.MatchingParen->Next &&
3911          Tok.MatchingParen->Next->isOneOf(tok::comma, tok::r_paren);
3912 }
3913 
3914 static bool
3915 isItAnEmptyLambdaAllowed(const FormatToken &Tok,
3916                          FormatStyle::ShortLambdaStyle ShortLambdaOption) {
3917   return Tok.Children.empty() && ShortLambdaOption != FormatStyle::SLS_None;
3918 }
3919 
3920 static bool isAllmanLambdaBrace(const FormatToken &Tok) {
3921   return Tok.is(tok::l_brace) && Tok.is(BK_Block) &&
3922          !Tok.isOneOf(TT_ObjCBlockLBrace, TT_DictLiteral);
3923 }
3924 
3925 // Returns the first token on the line that is not a comment.
3926 static const FormatToken *getFirstNonComment(const AnnotatedLine &Line) {
3927   const FormatToken *Next = Line.First;
3928   if (!Next)
3929     return Next;
3930   if (Next->is(tok::comment))
3931     Next = Next->getNextNonComment();
3932   return Next;
3933 }
3934 
3935 bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
3936                                      const FormatToken &Right) const {
3937   const FormatToken &Left = *Right.Previous;
3938   if (Right.NewlinesBefore > 1 && Style.MaxEmptyLinesToKeep > 0)
3939     return true;
3940 
3941   if (Style.isCSharp()) {
3942     if (Left.is(TT_FatArrow) && Right.is(tok::l_brace) &&
3943         Style.BraceWrapping.AfterFunction)
3944       return true;
3945     if (Right.is(TT_CSharpNamedArgumentColon) ||
3946         Left.is(TT_CSharpNamedArgumentColon))
3947       return false;
3948     if (Right.is(TT_CSharpGenericTypeConstraint))
3949       return true;
3950     if (Right.Next && Right.Next->is(TT_FatArrow) &&
3951         (Right.is(tok::numeric_constant) ||
3952          (Right.is(tok::identifier) && Right.TokenText == "_")))
3953       return true;
3954 
3955     // Break after C# [...] and before public/protected/private/internal.
3956     if (Left.is(TT_AttributeSquare) && Left.is(tok::r_square) &&
3957         (Right.isAccessSpecifier(/*ColonRequired=*/false) ||
3958          Right.is(Keywords.kw_internal)))
3959       return true;
3960     // Break between ] and [ but only when there are really 2 attributes.
3961     if (Left.is(TT_AttributeSquare) && Right.is(TT_AttributeSquare) &&
3962         Left.is(tok::r_square) && Right.is(tok::l_square))
3963       return true;
3964 
3965   } else if (Style.isJavaScript()) {
3966     // FIXME: This might apply to other languages and token kinds.
3967     if (Right.is(tok::string_literal) && Left.is(tok::plus) && Left.Previous &&
3968         Left.Previous->is(tok::string_literal))
3969       return true;
3970     if (Left.is(TT_DictLiteral) && Left.is(tok::l_brace) && Line.Level == 0 &&
3971         Left.Previous && Left.Previous->is(tok::equal) &&
3972         Line.First->isOneOf(tok::identifier, Keywords.kw_import, tok::kw_export,
3973                             tok::kw_const) &&
3974         // kw_var/kw_let are pseudo-tokens that are tok::identifier, so match
3975         // above.
3976         !Line.First->isOneOf(Keywords.kw_var, Keywords.kw_let))
3977       // Object literals on the top level of a file are treated as "enum-style".
3978       // Each key/value pair is put on a separate line, instead of bin-packing.
3979       return true;
3980     if (Left.is(tok::l_brace) && Line.Level == 0 &&
3981         (Line.startsWith(tok::kw_enum) ||
3982          Line.startsWith(tok::kw_const, tok::kw_enum) ||
3983          Line.startsWith(tok::kw_export, tok::kw_enum) ||
3984          Line.startsWith(tok::kw_export, tok::kw_const, tok::kw_enum)))
3985       // JavaScript top-level enum key/value pairs are put on separate lines
3986       // instead of bin-packing.
3987       return true;
3988     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) && Left.Previous &&
3989         Left.Previous->is(TT_FatArrow)) {
3990       // JS arrow function (=> {...}).
3991       switch (Style.AllowShortLambdasOnASingleLine) {
3992       case FormatStyle::SLS_All:
3993         return false;
3994       case FormatStyle::SLS_None:
3995         return true;
3996       case FormatStyle::SLS_Empty:
3997         return !Left.Children.empty();
3998       case FormatStyle::SLS_Inline:
3999         // allow one-lining inline (e.g. in function call args) and empty arrow
4000         // functions.
4001         return (Left.NestingLevel == 0 && Line.Level == 0) &&
4002                !Left.Children.empty();
4003       }
4004       llvm_unreachable("Unknown FormatStyle::ShortLambdaStyle enum");
4005     }
4006 
4007     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) &&
4008         !Left.Children.empty())
4009       // Support AllowShortFunctionsOnASingleLine for JavaScript.
4010       return Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_None ||
4011              Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Empty ||
4012              (Left.NestingLevel == 0 && Line.Level == 0 &&
4013               Style.AllowShortFunctionsOnASingleLine &
4014                   FormatStyle::SFS_InlineOnly);
4015   } else if (Style.Language == FormatStyle::LK_Java) {
4016     if (Right.is(tok::plus) && Left.is(tok::string_literal) && Right.Next &&
4017         Right.Next->is(tok::string_literal))
4018       return true;
4019   } else if (Style.Language == FormatStyle::LK_Cpp ||
4020              Style.Language == FormatStyle::LK_ObjC ||
4021              Style.Language == FormatStyle::LK_Proto ||
4022              Style.Language == FormatStyle::LK_TableGen ||
4023              Style.Language == FormatStyle::LK_TextProto) {
4024     if (Left.isStringLiteral() && Right.isStringLiteral())
4025       return true;
4026   }
4027 
4028   // Basic JSON newline processing.
4029   if (Style.isJson()) {
4030     // Always break after a JSON record opener.
4031     // {
4032     // }
4033     if (Left.is(TT_DictLiteral) && Left.is(tok::l_brace))
4034       return true;
4035     // Always break after a JSON array opener.
4036     // [
4037     // ]
4038     if (Left.is(TT_ArrayInitializerLSquare) && Left.is(tok::l_square) &&
4039         !Right.is(tok::r_square))
4040       return true;
4041     // Always break after successive entries.
4042     // 1,
4043     // 2
4044     if (Left.is(tok::comma))
4045       return true;
4046   }
4047 
4048   // If the last token before a '}', ']', or ')' is a comma or a trailing
4049   // comment, the intention is to insert a line break after it in order to make
4050   // shuffling around entries easier. Import statements, especially in
4051   // JavaScript, can be an exception to this rule.
4052   if (Style.JavaScriptWrapImports || Line.Type != LT_ImportStatement) {
4053     const FormatToken *BeforeClosingBrace = nullptr;
4054     if ((Left.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
4055          (Style.isJavaScript() && Left.is(tok::l_paren))) &&
4056         Left.isNot(BK_Block) && Left.MatchingParen)
4057       BeforeClosingBrace = Left.MatchingParen->Previous;
4058     else if (Right.MatchingParen &&
4059              (Right.MatchingParen->isOneOf(tok::l_brace,
4060                                            TT_ArrayInitializerLSquare) ||
4061               (Style.isJavaScript() && Right.MatchingParen->is(tok::l_paren))))
4062       BeforeClosingBrace = &Left;
4063     if (BeforeClosingBrace && (BeforeClosingBrace->is(tok::comma) ||
4064                                BeforeClosingBrace->isTrailingComment()))
4065       return true;
4066   }
4067 
4068   if (Right.is(tok::comment))
4069     return Left.isNot(BK_BracedInit) && Left.isNot(TT_CtorInitializerColon) &&
4070            (Right.NewlinesBefore > 0 && Right.HasUnescapedNewline);
4071   if (Left.isTrailingComment())
4072     return true;
4073   if (Left.IsUnterminatedLiteral)
4074     return true;
4075   if (Right.is(tok::lessless) && Right.Next && Left.is(tok::string_literal) &&
4076       Right.Next->is(tok::string_literal))
4077     return true;
4078   if (Right.is(TT_RequiresClause)) {
4079     switch (Style.RequiresClausePosition) {
4080     case FormatStyle::RCPS_OwnLine:
4081     case FormatStyle::RCPS_WithFollowing:
4082       return true;
4083     default:
4084       break;
4085     }
4086   }
4087   // Can break after template<> declaration
4088   if (Left.ClosesTemplateDeclaration && Left.MatchingParen &&
4089       Left.MatchingParen->NestingLevel == 0) {
4090     // Put concepts on the next line e.g.
4091     // template<typename T>
4092     // concept ...
4093     if (Right.is(tok::kw_concept))
4094       return Style.BreakBeforeConceptDeclarations == FormatStyle::BBCDS_Always;
4095     return Style.AlwaysBreakTemplateDeclarations == FormatStyle::BTDS_Yes;
4096   }
4097   if (Left.ClosesRequiresClause && Right.isNot(tok::semi)) {
4098     switch (Style.RequiresClausePosition) {
4099     case FormatStyle::RCPS_OwnLine:
4100     case FormatStyle::RCPS_WithPreceding:
4101       return true;
4102     default:
4103       break;
4104     }
4105   }
4106   if (Style.PackConstructorInitializers == FormatStyle::PCIS_Never) {
4107     if (Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeColon &&
4108         (Left.is(TT_CtorInitializerComma) || Right.is(TT_CtorInitializerColon)))
4109       return true;
4110 
4111     if (Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon &&
4112         Left.isOneOf(TT_CtorInitializerColon, TT_CtorInitializerComma))
4113       return true;
4114   }
4115   if (Style.PackConstructorInitializers < FormatStyle::PCIS_CurrentLine &&
4116       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma &&
4117       Right.isOneOf(TT_CtorInitializerComma, TT_CtorInitializerColon))
4118     return true;
4119   // Break only if we have multiple inheritance.
4120   if (Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma &&
4121       Right.is(TT_InheritanceComma))
4122     return true;
4123   if (Style.BreakInheritanceList == FormatStyle::BILS_AfterComma &&
4124       Left.is(TT_InheritanceComma))
4125     return true;
4126   if (Right.is(tok::string_literal) && Right.TokenText.startswith("R\""))
4127     // Multiline raw string literals are special wrt. line breaks. The author
4128     // has made a deliberate choice and might have aligned the contents of the
4129     // string literal accordingly. Thus, we try keep existing line breaks.
4130     return Right.IsMultiline && Right.NewlinesBefore > 0;
4131   if ((Left.is(tok::l_brace) || (Left.is(tok::less) && Left.Previous &&
4132                                  Left.Previous->is(tok::equal))) &&
4133       Right.NestingLevel == 1 && Style.Language == FormatStyle::LK_Proto) {
4134     // Don't put enums or option definitions onto single lines in protocol
4135     // buffers.
4136     return true;
4137   }
4138   if (Right.is(TT_InlineASMBrace))
4139     return Right.HasUnescapedNewline;
4140 
4141   if (isAllmanBrace(Left) || isAllmanBrace(Right)) {
4142     auto FirstNonComment = getFirstNonComment(Line);
4143     bool AccessSpecifier =
4144         FirstNonComment &&
4145         FirstNonComment->isOneOf(Keywords.kw_internal, tok::kw_public,
4146                                  tok::kw_private, tok::kw_protected);
4147 
4148     if (Style.BraceWrapping.AfterEnum) {
4149       if (Line.startsWith(tok::kw_enum) ||
4150           Line.startsWith(tok::kw_typedef, tok::kw_enum))
4151         return true;
4152       // Ensure BraceWrapping for `public enum A {`.
4153       if (AccessSpecifier && FirstNonComment->Next &&
4154           FirstNonComment->Next->is(tok::kw_enum))
4155         return true;
4156     }
4157 
4158     // Ensure BraceWrapping for `public interface A {`.
4159     if (Style.BraceWrapping.AfterClass &&
4160         ((AccessSpecifier && FirstNonComment->Next &&
4161           FirstNonComment->Next->is(Keywords.kw_interface)) ||
4162          Line.startsWith(Keywords.kw_interface)))
4163       return true;
4164 
4165     return (Line.startsWith(tok::kw_class) && Style.BraceWrapping.AfterClass) ||
4166            (Line.startsWith(tok::kw_struct) && Style.BraceWrapping.AfterStruct);
4167   }
4168 
4169   if (Left.is(TT_ObjCBlockLBrace) &&
4170       Style.AllowShortBlocksOnASingleLine == FormatStyle::SBS_Never)
4171     return true;
4172 
4173   // Ensure wrapping after __attribute__((XX)) and @interface etc.
4174   if (Left.is(TT_AttributeParen) && Right.is(TT_ObjCDecl))
4175     return true;
4176 
4177   if (Left.is(TT_LambdaLBrace)) {
4178     if (IsFunctionArgument(Left) &&
4179         Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_Inline)
4180       return false;
4181 
4182     if (Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_None ||
4183         Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_Inline ||
4184         (!Left.Children.empty() &&
4185          Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_Empty))
4186       return true;
4187   }
4188 
4189   if (Style.BraceWrapping.BeforeLambdaBody && Right.is(TT_LambdaLBrace) &&
4190       Left.isOneOf(tok::star, tok::amp, tok::ampamp, TT_TemplateCloser))
4191     return true;
4192 
4193   // Put multiple Java annotation on a new line.
4194   if ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
4195       Left.is(TT_LeadingJavaAnnotation) &&
4196       Right.isNot(TT_LeadingJavaAnnotation) && Right.isNot(tok::l_paren) &&
4197       (Line.Last->is(tok::l_brace) || Style.BreakAfterJavaFieldAnnotations))
4198     return true;
4199 
4200   if (Right.is(TT_ProtoExtensionLSquare))
4201     return true;
4202 
4203   // In text proto instances if a submessage contains at least 2 entries and at
4204   // least one of them is a submessage, like A { ... B { ... } ... },
4205   // put all of the entries of A on separate lines by forcing the selector of
4206   // the submessage B to be put on a newline.
4207   //
4208   // Example: these can stay on one line:
4209   // a { scalar_1: 1 scalar_2: 2 }
4210   // a { b { key: value } }
4211   //
4212   // and these entries need to be on a new line even if putting them all in one
4213   // line is under the column limit:
4214   // a {
4215   //   scalar: 1
4216   //   b { key: value }
4217   // }
4218   //
4219   // We enforce this by breaking before a submessage field that has previous
4220   // siblings, *and* breaking before a field that follows a submessage field.
4221   //
4222   // Be careful to exclude the case  [proto.ext] { ... } since the `]` is
4223   // the TT_SelectorName there, but we don't want to break inside the brackets.
4224   //
4225   // Another edge case is @submessage { key: value }, which is a common
4226   // substitution placeholder. In this case we want to keep `@` and `submessage`
4227   // together.
4228   //
4229   // We ensure elsewhere that extensions are always on their own line.
4230   if ((Style.Language == FormatStyle::LK_Proto ||
4231        Style.Language == FormatStyle::LK_TextProto) &&
4232       Right.is(TT_SelectorName) && !Right.is(tok::r_square) && Right.Next) {
4233     // Keep `@submessage` together in:
4234     // @submessage { key: value }
4235     if (Left.is(tok::at))
4236       return false;
4237     // Look for the scope opener after selector in cases like:
4238     // selector { ...
4239     // selector: { ...
4240     // selector: @base { ...
4241     FormatToken *LBrace = Right.Next;
4242     if (LBrace && LBrace->is(tok::colon)) {
4243       LBrace = LBrace->Next;
4244       if (LBrace && LBrace->is(tok::at)) {
4245         LBrace = LBrace->Next;
4246         if (LBrace)
4247           LBrace = LBrace->Next;
4248       }
4249     }
4250     if (LBrace &&
4251         // The scope opener is one of {, [, <:
4252         // selector { ... }
4253         // selector [ ... ]
4254         // selector < ... >
4255         //
4256         // In case of selector { ... }, the l_brace is TT_DictLiteral.
4257         // In case of an empty selector {}, the l_brace is not TT_DictLiteral,
4258         // so we check for immediately following r_brace.
4259         ((LBrace->is(tok::l_brace) &&
4260           (LBrace->is(TT_DictLiteral) ||
4261            (LBrace->Next && LBrace->Next->is(tok::r_brace)))) ||
4262          LBrace->is(TT_ArrayInitializerLSquare) || LBrace->is(tok::less))) {
4263       // If Left.ParameterCount is 0, then this submessage entry is not the
4264       // first in its parent submessage, and we want to break before this entry.
4265       // If Left.ParameterCount is greater than 0, then its parent submessage
4266       // might contain 1 or more entries and we want to break before this entry
4267       // if it contains at least 2 entries. We deal with this case later by
4268       // detecting and breaking before the next entry in the parent submessage.
4269       if (Left.ParameterCount == 0)
4270         return true;
4271       // However, if this submessage is the first entry in its parent
4272       // submessage, Left.ParameterCount might be 1 in some cases.
4273       // We deal with this case later by detecting an entry
4274       // following a closing paren of this submessage.
4275     }
4276 
4277     // If this is an entry immediately following a submessage, it will be
4278     // preceded by a closing paren of that submessage, like in:
4279     //     left---.  .---right
4280     //            v  v
4281     // sub: { ... } key: value
4282     // If there was a comment between `}` an `key` above, then `key` would be
4283     // put on a new line anyways.
4284     if (Left.isOneOf(tok::r_brace, tok::greater, tok::r_square))
4285       return true;
4286   }
4287 
4288   // Deal with lambda arguments in C++ - we want consistent line breaks whether
4289   // they happen to be at arg0, arg1 or argN. The selection is a bit nuanced
4290   // as aggressive line breaks are placed when the lambda is not the last arg.
4291   if ((Style.Language == FormatStyle::LK_Cpp ||
4292        Style.Language == FormatStyle::LK_ObjC) &&
4293       Left.is(tok::l_paren) && Left.BlockParameterCount > 0 &&
4294       !Right.isOneOf(tok::l_paren, TT_LambdaLSquare)) {
4295     // Multiple lambdas in the same function call force line breaks.
4296     if (Left.BlockParameterCount > 1)
4297       return true;
4298 
4299     // A lambda followed by another arg forces a line break.
4300     if (!Left.Role)
4301       return false;
4302     auto Comma = Left.Role->lastComma();
4303     if (!Comma)
4304       return false;
4305     auto Next = Comma->getNextNonComment();
4306     if (!Next)
4307       return false;
4308     if (!Next->isOneOf(TT_LambdaLSquare, tok::l_brace, tok::caret))
4309       return true;
4310   }
4311 
4312   return false;
4313 }
4314 
4315 bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
4316                                     const FormatToken &Right) const {
4317   const FormatToken &Left = *Right.Previous;
4318   // Language-specific stuff.
4319   if (Style.isCSharp()) {
4320     if (Left.isOneOf(TT_CSharpNamedArgumentColon, TT_AttributeColon) ||
4321         Right.isOneOf(TT_CSharpNamedArgumentColon, TT_AttributeColon))
4322       return false;
4323     // Only break after commas for generic type constraints.
4324     if (Line.First->is(TT_CSharpGenericTypeConstraint))
4325       return Left.is(TT_CSharpGenericTypeConstraintComma);
4326     // Keep nullable operators attached to their identifiers.
4327     if (Right.is(TT_CSharpNullable))
4328       return false;
4329   } else if (Style.Language == FormatStyle::LK_Java) {
4330     if (Left.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
4331                      Keywords.kw_implements))
4332       return false;
4333     if (Right.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
4334                       Keywords.kw_implements))
4335       return true;
4336   } else if (Style.isJavaScript()) {
4337     const FormatToken *NonComment = Right.getPreviousNonComment();
4338     if (NonComment &&
4339         NonComment->isOneOf(
4340             tok::kw_return, Keywords.kw_yield, tok::kw_continue, tok::kw_break,
4341             tok::kw_throw, Keywords.kw_interface, Keywords.kw_type,
4342             tok::kw_static, tok::kw_public, tok::kw_private, tok::kw_protected,
4343             Keywords.kw_readonly, Keywords.kw_override, Keywords.kw_abstract,
4344             Keywords.kw_get, Keywords.kw_set, Keywords.kw_async,
4345             Keywords.kw_await))
4346       return false; // Otherwise automatic semicolon insertion would trigger.
4347     if (Right.NestingLevel == 0 &&
4348         (Left.Tok.getIdentifierInfo() ||
4349          Left.isOneOf(tok::r_square, tok::r_paren)) &&
4350         Right.isOneOf(tok::l_square, tok::l_paren))
4351       return false; // Otherwise automatic semicolon insertion would trigger.
4352     if (NonComment && NonComment->is(tok::identifier) &&
4353         NonComment->TokenText == "asserts")
4354       return false;
4355     if (Left.is(TT_FatArrow) && Right.is(tok::l_brace))
4356       return false;
4357     if (Left.is(TT_JsTypeColon))
4358       return true;
4359     // Don't wrap between ":" and "!" of a strict prop init ("field!: type;").
4360     if (Left.is(tok::exclaim) && Right.is(tok::colon))
4361       return false;
4362     // Look for is type annotations like:
4363     // function f(): a is B { ... }
4364     // Do not break before is in these cases.
4365     if (Right.is(Keywords.kw_is)) {
4366       const FormatToken *Next = Right.getNextNonComment();
4367       // If `is` is followed by a colon, it's likely that it's a dict key, so
4368       // ignore it for this check.
4369       // For example this is common in Polymer:
4370       // Polymer({
4371       //   is: 'name',
4372       //   ...
4373       // });
4374       if (!Next || !Next->is(tok::colon))
4375         return false;
4376     }
4377     if (Left.is(Keywords.kw_in))
4378       return Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None;
4379     if (Right.is(Keywords.kw_in))
4380       return Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None;
4381     if (Right.is(Keywords.kw_as))
4382       return false; // must not break before as in 'x as type' casts
4383     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_infer)) {
4384       // extends and infer can appear as keywords in conditional types:
4385       //   https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html#conditional-types
4386       // do not break before them, as the expressions are subject to ASI.
4387       return false;
4388     }
4389     if (Left.is(Keywords.kw_as))
4390       return true;
4391     if (Left.is(TT_NonNullAssertion))
4392       return true;
4393     if (Left.is(Keywords.kw_declare) &&
4394         Right.isOneOf(Keywords.kw_module, tok::kw_namespace,
4395                       Keywords.kw_function, tok::kw_class, tok::kw_enum,
4396                       Keywords.kw_interface, Keywords.kw_type, Keywords.kw_var,
4397                       Keywords.kw_let, tok::kw_const))
4398       // See grammar for 'declare' statements at:
4399       // https://github.com/Microsoft/TypeScript/blob/main/doc/spec-ARCHIVED.md#A.10
4400       return false;
4401     if (Left.isOneOf(Keywords.kw_module, tok::kw_namespace) &&
4402         Right.isOneOf(tok::identifier, tok::string_literal))
4403       return false; // must not break in "module foo { ...}"
4404     if (Right.is(TT_TemplateString) && Right.closesScope())
4405       return false;
4406     // Don't split tagged template literal so there is a break between the tag
4407     // identifier and template string.
4408     if (Left.is(tok::identifier) && Right.is(TT_TemplateString))
4409       return false;
4410     if (Left.is(TT_TemplateString) && Left.opensScope())
4411       return true;
4412   }
4413 
4414   if (Left.is(tok::at))
4415     return false;
4416   if (Left.Tok.getObjCKeywordID() == tok::objc_interface)
4417     return false;
4418   if (Left.isOneOf(TT_JavaAnnotation, TT_LeadingJavaAnnotation))
4419     return !Right.is(tok::l_paren);
4420   if (Right.is(TT_PointerOrReference))
4421     return Line.IsMultiVariableDeclStmt ||
4422            (getTokenPointerOrReferenceAlignment(Right) ==
4423                 FormatStyle::PAS_Right &&
4424             (!Right.Next || Right.Next->isNot(TT_FunctionDeclarationName)));
4425   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
4426       Right.is(tok::kw_operator))
4427     return true;
4428   if (Left.is(TT_PointerOrReference))
4429     return false;
4430   if (Right.isTrailingComment())
4431     // We rely on MustBreakBefore being set correctly here as we should not
4432     // change the "binding" behavior of a comment.
4433     // The first comment in a braced lists is always interpreted as belonging to
4434     // the first list element. Otherwise, it should be placed outside of the
4435     // list.
4436     return Left.is(BK_BracedInit) ||
4437            (Left.is(TT_CtorInitializerColon) &&
4438             Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon);
4439   if (Left.is(tok::question) && Right.is(tok::colon))
4440     return false;
4441   if (Right.is(TT_ConditionalExpr) || Right.is(tok::question))
4442     return Style.BreakBeforeTernaryOperators;
4443   if (Left.is(TT_ConditionalExpr) || Left.is(tok::question))
4444     return !Style.BreakBeforeTernaryOperators;
4445   if (Left.is(TT_InheritanceColon))
4446     return Style.BreakInheritanceList == FormatStyle::BILS_AfterColon;
4447   if (Right.is(TT_InheritanceColon))
4448     return Style.BreakInheritanceList != FormatStyle::BILS_AfterColon;
4449   if (Right.is(TT_ObjCMethodExpr) && !Right.is(tok::r_square) &&
4450       Left.isNot(TT_SelectorName))
4451     return true;
4452 
4453   if (Right.is(tok::colon) &&
4454       !Right.isOneOf(TT_CtorInitializerColon, TT_InlineASMColon))
4455     return false;
4456   if (Left.is(tok::colon) && Left.isOneOf(TT_DictLiteral, TT_ObjCMethodExpr)) {
4457     if (Style.Language == FormatStyle::LK_Proto ||
4458         Style.Language == FormatStyle::LK_TextProto) {
4459       if (!Style.AlwaysBreakBeforeMultilineStrings && Right.isStringLiteral())
4460         return false;
4461       // Prevent cases like:
4462       //
4463       // submessage:
4464       //     { key: valueeeeeeeeeeee }
4465       //
4466       // when the snippet does not fit into one line.
4467       // Prefer:
4468       //
4469       // submessage: {
4470       //   key: valueeeeeeeeeeee
4471       // }
4472       //
4473       // instead, even if it is longer by one line.
4474       //
4475       // Note that this allows allows the "{" to go over the column limit
4476       // when the column limit is just between ":" and "{", but that does
4477       // not happen too often and alternative formattings in this case are
4478       // not much better.
4479       //
4480       // The code covers the cases:
4481       //
4482       // submessage: { ... }
4483       // submessage: < ... >
4484       // repeated: [ ... ]
4485       if (((Right.is(tok::l_brace) || Right.is(tok::less)) &&
4486            Right.is(TT_DictLiteral)) ||
4487           Right.is(TT_ArrayInitializerLSquare))
4488         return false;
4489     }
4490     return true;
4491   }
4492   if (Right.is(tok::r_square) && Right.MatchingParen &&
4493       Right.MatchingParen->is(TT_ProtoExtensionLSquare))
4494     return false;
4495   if (Right.is(TT_SelectorName) || (Right.is(tok::identifier) && Right.Next &&
4496                                     Right.Next->is(TT_ObjCMethodExpr)))
4497     return Left.isNot(tok::period); // FIXME: Properly parse ObjC calls.
4498   if (Left.is(tok::r_paren) && Line.Type == LT_ObjCProperty)
4499     return true;
4500   if (Right.is(tok::kw_concept))
4501     return Style.BreakBeforeConceptDeclarations != FormatStyle::BBCDS_Never;
4502   if (Right.is(TT_RequiresClause))
4503     return true;
4504   if (Left.ClosesTemplateDeclaration || Left.is(TT_FunctionAnnotationRParen))
4505     return true;
4506   if (Left.ClosesRequiresClause)
4507     return true;
4508   if (Right.isOneOf(TT_RangeBasedForLoopColon, TT_OverloadedOperatorLParen,
4509                     TT_OverloadedOperator))
4510     return false;
4511   if (Left.is(TT_RangeBasedForLoopColon))
4512     return true;
4513   if (Right.is(TT_RangeBasedForLoopColon))
4514     return false;
4515   if (Left.is(TT_TemplateCloser) && Right.is(TT_TemplateOpener))
4516     return true;
4517   if ((Left.is(tok::greater) && Right.is(tok::greater)) ||
4518       (Left.is(tok::less) && Right.is(tok::less)))
4519     return false;
4520   if (Right.is(TT_BinaryOperator) &&
4521       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None &&
4522       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_All ||
4523        Right.getPrecedence() != prec::Assignment))
4524     return true;
4525   if (Left.isOneOf(TT_TemplateCloser, TT_UnaryOperator) ||
4526       Left.is(tok::kw_operator))
4527     return false;
4528   if (Left.is(tok::equal) && !Right.isOneOf(tok::kw_default, tok::kw_delete) &&
4529       Line.Type == LT_VirtualFunctionDecl && Left.NestingLevel == 0)
4530     return false;
4531   if (Left.is(tok::equal) && Right.is(tok::l_brace) &&
4532       !Style.Cpp11BracedListStyle)
4533     return false;
4534   if (Left.is(tok::l_paren) &&
4535       Left.isOneOf(TT_AttributeParen, TT_TypeDeclarationParen))
4536     return false;
4537   if (Left.is(tok::l_paren) && Left.Previous &&
4538       (Left.Previous->isOneOf(TT_BinaryOperator, TT_CastRParen)))
4539     return false;
4540   if (Right.is(TT_ImplicitStringLiteral))
4541     return false;
4542 
4543   if (Right.is(TT_TemplateCloser))
4544     return false;
4545   if (Right.is(tok::r_square) && Right.MatchingParen &&
4546       Right.MatchingParen->is(TT_LambdaLSquare))
4547     return false;
4548 
4549   // We only break before r_brace if there was a corresponding break before
4550   // the l_brace, which is tracked by BreakBeforeClosingBrace.
4551   if (Right.is(tok::r_brace))
4552     return Right.MatchingParen && Right.MatchingParen->is(BK_Block);
4553 
4554   // We only break before r_paren if we're in a block indented context.
4555   if (Right.is(tok::r_paren)) {
4556     if (Style.AlignAfterOpenBracket != FormatStyle::BAS_BlockIndent ||
4557         !Right.MatchingParen)
4558       return false;
4559     const FormatToken *Previous = Right.MatchingParen->Previous;
4560     return !(Previous && (Previous->is(tok::kw_for) || Previous->isIf()));
4561   }
4562 
4563   // Allow breaking after a trailing annotation, e.g. after a method
4564   // declaration.
4565   if (Left.is(TT_TrailingAnnotation))
4566     return !Right.isOneOf(tok::l_brace, tok::semi, tok::equal, tok::l_paren,
4567                           tok::less, tok::coloncolon);
4568 
4569   if (Right.is(tok::kw___attribute) ||
4570       (Right.is(tok::l_square) && Right.is(TT_AttributeSquare)))
4571     return !Left.is(TT_AttributeSquare);
4572 
4573   if (Left.is(tok::identifier) && Right.is(tok::string_literal))
4574     return true;
4575 
4576   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
4577     return true;
4578 
4579   if (Left.is(TT_CtorInitializerColon))
4580     return Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon;
4581   if (Right.is(TT_CtorInitializerColon))
4582     return Style.BreakConstructorInitializers != FormatStyle::BCIS_AfterColon;
4583   if (Left.is(TT_CtorInitializerComma) &&
4584       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma)
4585     return false;
4586   if (Right.is(TT_CtorInitializerComma) &&
4587       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma)
4588     return true;
4589   if (Left.is(TT_InheritanceComma) &&
4590       Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma)
4591     return false;
4592   if (Right.is(TT_InheritanceComma) &&
4593       Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma)
4594     return true;
4595   if (Left.is(TT_ArrayInitializerLSquare))
4596     return true;
4597   if (Right.is(tok::kw_typename) && Left.isNot(tok::kw_const))
4598     return true;
4599   if ((Left.isBinaryOperator() || Left.is(TT_BinaryOperator)) &&
4600       !Left.isOneOf(tok::arrowstar, tok::lessless) &&
4601       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_All &&
4602       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None ||
4603        Left.getPrecedence() == prec::Assignment))
4604     return true;
4605   if ((Left.is(TT_AttributeSquare) && Right.is(tok::l_square)) ||
4606       (Left.is(tok::r_square) && Right.is(TT_AttributeSquare)))
4607     return false;
4608 
4609   auto ShortLambdaOption = Style.AllowShortLambdasOnASingleLine;
4610   if (Style.BraceWrapping.BeforeLambdaBody && Right.is(TT_LambdaLBrace)) {
4611     if (isAllmanLambdaBrace(Left))
4612       return !isItAnEmptyLambdaAllowed(Left, ShortLambdaOption);
4613     if (isAllmanLambdaBrace(Right))
4614       return !isItAnEmptyLambdaAllowed(Right, ShortLambdaOption);
4615   }
4616 
4617   return Left.isOneOf(tok::comma, tok::coloncolon, tok::semi, tok::l_brace,
4618                       tok::kw_class, tok::kw_struct, tok::comment) ||
4619          Right.isMemberAccess() ||
4620          Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow, tok::lessless,
4621                        tok::colon, tok::l_square, tok::at) ||
4622          (Left.is(tok::r_paren) &&
4623           Right.isOneOf(tok::identifier, tok::kw_const)) ||
4624          (Left.is(tok::l_paren) && !Right.is(tok::r_paren)) ||
4625          (Left.is(TT_TemplateOpener) && !Right.is(TT_TemplateCloser));
4626 }
4627 
4628 void TokenAnnotator::printDebugInfo(const AnnotatedLine &Line) const {
4629   llvm::errs() << "AnnotatedTokens(L=" << Line.Level << "):\n";
4630   const FormatToken *Tok = Line.First;
4631   while (Tok) {
4632     llvm::errs() << " M=" << Tok->MustBreakBefore
4633                  << " C=" << Tok->CanBreakBefore
4634                  << " T=" << getTokenTypeName(Tok->getType())
4635                  << " S=" << Tok->SpacesRequiredBefore
4636                  << " F=" << Tok->Finalized << " B=" << Tok->BlockParameterCount
4637                  << " BK=" << Tok->getBlockKind() << " P=" << Tok->SplitPenalty
4638                  << " Name=" << Tok->Tok.getName() << " L=" << Tok->TotalLength
4639                  << " PPK=" << Tok->getPackingKind() << " FakeLParens=";
4640     for (prec::Level LParen : Tok->FakeLParens)
4641       llvm::errs() << LParen << "/";
4642     llvm::errs() << " FakeRParens=" << Tok->FakeRParens;
4643     llvm::errs() << " II=" << Tok->Tok.getIdentifierInfo();
4644     llvm::errs() << " Text='" << Tok->TokenText << "'\n";
4645     if (!Tok->Next)
4646       assert(Tok == Line.Last);
4647     Tok = Tok->Next;
4648   }
4649   llvm::errs() << "----\n";
4650 }
4651 
4652 FormatStyle::PointerAlignmentStyle
4653 TokenAnnotator::getTokenReferenceAlignment(const FormatToken &Reference) const {
4654   assert(Reference.isOneOf(tok::amp, tok::ampamp));
4655   switch (Style.ReferenceAlignment) {
4656   case FormatStyle::RAS_Pointer:
4657     return Style.PointerAlignment;
4658   case FormatStyle::RAS_Left:
4659     return FormatStyle::PAS_Left;
4660   case FormatStyle::RAS_Right:
4661     return FormatStyle::PAS_Right;
4662   case FormatStyle::RAS_Middle:
4663     return FormatStyle::PAS_Middle;
4664   }
4665   assert(0); //"Unhandled value of ReferenceAlignment"
4666   return Style.PointerAlignment;
4667 }
4668 
4669 FormatStyle::PointerAlignmentStyle
4670 TokenAnnotator::getTokenPointerOrReferenceAlignment(
4671     const FormatToken &PointerOrReference) const {
4672   if (PointerOrReference.isOneOf(tok::amp, tok::ampamp)) {
4673     switch (Style.ReferenceAlignment) {
4674     case FormatStyle::RAS_Pointer:
4675       return Style.PointerAlignment;
4676     case FormatStyle::RAS_Left:
4677       return FormatStyle::PAS_Left;
4678     case FormatStyle::RAS_Right:
4679       return FormatStyle::PAS_Right;
4680     case FormatStyle::RAS_Middle:
4681       return FormatStyle::PAS_Middle;
4682     }
4683   }
4684   assert(PointerOrReference.is(tok::star));
4685   return Style.PointerAlignment;
4686 }
4687 
4688 } // namespace format
4689 } // namespace clang
4690