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->Previous && Tok->Previous->is(tok::kw_noexcept))
1189         Tok->setType(TT_TrailingReturnArrow);
1190       break;
1191     default:
1192       break;
1193     }
1194     return true;
1195   }
1196 
1197   void parseCSharpGenericTypeConstraint() {
1198     int OpenAngleBracketsCount = 0;
1199     while (CurrentToken) {
1200       if (CurrentToken->is(tok::less)) {
1201         // parseAngle is too greedy and will consume the whole line.
1202         CurrentToken->setType(TT_TemplateOpener);
1203         ++OpenAngleBracketsCount;
1204         next();
1205       } else if (CurrentToken->is(tok::greater)) {
1206         CurrentToken->setType(TT_TemplateCloser);
1207         --OpenAngleBracketsCount;
1208         next();
1209       } else if (CurrentToken->is(tok::comma) && OpenAngleBracketsCount == 0) {
1210         // We allow line breaks after GenericTypeConstraintComma's
1211         // so do not flag commas in Generics as GenericTypeConstraintComma's.
1212         CurrentToken->setType(TT_CSharpGenericTypeConstraintComma);
1213         next();
1214       } else if (CurrentToken->is(Keywords.kw_where)) {
1215         CurrentToken->setType(TT_CSharpGenericTypeConstraint);
1216         next();
1217       } else if (CurrentToken->is(tok::colon)) {
1218         CurrentToken->setType(TT_CSharpGenericTypeConstraintColon);
1219         next();
1220       } else {
1221         next();
1222       }
1223     }
1224   }
1225 
1226   void parseIncludeDirective() {
1227     if (CurrentToken && CurrentToken->is(tok::less)) {
1228       next();
1229       while (CurrentToken) {
1230         // Mark tokens up to the trailing line comments as implicit string
1231         // literals.
1232         if (CurrentToken->isNot(tok::comment) &&
1233             !CurrentToken->TokenText.startswith("//"))
1234           CurrentToken->setType(TT_ImplicitStringLiteral);
1235         next();
1236       }
1237     }
1238   }
1239 
1240   void parseWarningOrError() {
1241     next();
1242     // We still want to format the whitespace left of the first token of the
1243     // warning or error.
1244     next();
1245     while (CurrentToken) {
1246       CurrentToken->setType(TT_ImplicitStringLiteral);
1247       next();
1248     }
1249   }
1250 
1251   void parsePragma() {
1252     next(); // Consume "pragma".
1253     if (CurrentToken &&
1254         CurrentToken->isOneOf(Keywords.kw_mark, Keywords.kw_option)) {
1255       bool IsMark = CurrentToken->is(Keywords.kw_mark);
1256       next(); // Consume "mark".
1257       next(); // Consume first token (so we fix leading whitespace).
1258       while (CurrentToken) {
1259         if (IsMark || CurrentToken->Previous->is(TT_BinaryOperator))
1260           CurrentToken->setType(TT_ImplicitStringLiteral);
1261         next();
1262       }
1263     }
1264   }
1265 
1266   void parseHasInclude() {
1267     if (!CurrentToken || !CurrentToken->is(tok::l_paren))
1268       return;
1269     next(); // '('
1270     parseIncludeDirective();
1271     next(); // ')'
1272   }
1273 
1274   LineType parsePreprocessorDirective() {
1275     bool IsFirstToken = CurrentToken->IsFirst;
1276     LineType Type = LT_PreprocessorDirective;
1277     next();
1278     if (!CurrentToken)
1279       return Type;
1280 
1281     if (Style.isJavaScript() && IsFirstToken) {
1282       // JavaScript files can contain shebang lines of the form:
1283       // #!/usr/bin/env node
1284       // Treat these like C++ #include directives.
1285       while (CurrentToken) {
1286         // Tokens cannot be comments here.
1287         CurrentToken->setType(TT_ImplicitStringLiteral);
1288         next();
1289       }
1290       return LT_ImportStatement;
1291     }
1292 
1293     if (CurrentToken->is(tok::numeric_constant)) {
1294       CurrentToken->SpacesRequiredBefore = 1;
1295       return Type;
1296     }
1297     // Hashes in the middle of a line can lead to any strange token
1298     // sequence.
1299     if (!CurrentToken->Tok.getIdentifierInfo())
1300       return Type;
1301     switch (CurrentToken->Tok.getIdentifierInfo()->getPPKeywordID()) {
1302     case tok::pp_include:
1303     case tok::pp_include_next:
1304     case tok::pp_import:
1305       next();
1306       parseIncludeDirective();
1307       Type = LT_ImportStatement;
1308       break;
1309     case tok::pp_error:
1310     case tok::pp_warning:
1311       parseWarningOrError();
1312       break;
1313     case tok::pp_pragma:
1314       parsePragma();
1315       break;
1316     case tok::pp_if:
1317     case tok::pp_elif:
1318       Contexts.back().IsExpression = true;
1319       next();
1320       parseLine();
1321       break;
1322     default:
1323       break;
1324     }
1325     while (CurrentToken) {
1326       FormatToken *Tok = CurrentToken;
1327       next();
1328       if (Tok->is(tok::l_paren))
1329         parseParens();
1330       else if (Tok->isOneOf(Keywords.kw___has_include,
1331                             Keywords.kw___has_include_next))
1332         parseHasInclude();
1333     }
1334     return Type;
1335   }
1336 
1337 public:
1338   LineType parseLine() {
1339     if (!CurrentToken)
1340       return LT_Invalid;
1341     NonTemplateLess.clear();
1342     if (CurrentToken->is(tok::hash))
1343       return parsePreprocessorDirective();
1344 
1345     // Directly allow to 'import <string-literal>' to support protocol buffer
1346     // definitions (github.com/google/protobuf) or missing "#" (either way we
1347     // should not break the line).
1348     IdentifierInfo *Info = CurrentToken->Tok.getIdentifierInfo();
1349     if ((Style.Language == FormatStyle::LK_Java &&
1350          CurrentToken->is(Keywords.kw_package)) ||
1351         (Info && Info->getPPKeywordID() == tok::pp_import &&
1352          CurrentToken->Next &&
1353          CurrentToken->Next->isOneOf(tok::string_literal, tok::identifier,
1354                                      tok::kw_static))) {
1355       next();
1356       parseIncludeDirective();
1357       return LT_ImportStatement;
1358     }
1359 
1360     // If this line starts and ends in '<' and '>', respectively, it is likely
1361     // part of "#define <a/b.h>".
1362     if (CurrentToken->is(tok::less) && Line.Last->is(tok::greater)) {
1363       parseIncludeDirective();
1364       return LT_ImportStatement;
1365     }
1366 
1367     // In .proto files, top-level options and package statements are very
1368     // similar to import statements and should not be line-wrapped.
1369     if (Style.Language == FormatStyle::LK_Proto && Line.Level == 0 &&
1370         CurrentToken->isOneOf(Keywords.kw_option, Keywords.kw_package)) {
1371       next();
1372       if (CurrentToken && CurrentToken->is(tok::identifier)) {
1373         while (CurrentToken)
1374           next();
1375         return LT_ImportStatement;
1376       }
1377     }
1378 
1379     bool KeywordVirtualFound = false;
1380     bool ImportStatement = false;
1381 
1382     // import {...} from '...';
1383     if (Style.isJavaScript() && CurrentToken->is(Keywords.kw_import))
1384       ImportStatement = true;
1385 
1386     while (CurrentToken) {
1387       if (CurrentToken->is(tok::kw_virtual))
1388         KeywordVirtualFound = true;
1389       if (Style.isJavaScript()) {
1390         // export {...} from '...';
1391         // An export followed by "from 'some string';" is a re-export from
1392         // another module identified by a URI and is treated as a
1393         // LT_ImportStatement (i.e. prevent wraps on it for long URIs).
1394         // Just "export {...};" or "export class ..." should not be treated as
1395         // an import in this sense.
1396         if (Line.First->is(tok::kw_export) &&
1397             CurrentToken->is(Keywords.kw_from) && CurrentToken->Next &&
1398             CurrentToken->Next->isStringLiteral())
1399           ImportStatement = true;
1400         if (isClosureImportStatement(*CurrentToken))
1401           ImportStatement = true;
1402       }
1403       if (!consumeToken())
1404         return LT_Invalid;
1405     }
1406     if (KeywordVirtualFound)
1407       return LT_VirtualFunctionDecl;
1408     if (ImportStatement)
1409       return LT_ImportStatement;
1410 
1411     if (Line.startsWith(TT_ObjCMethodSpecifier)) {
1412       if (Contexts.back().FirstObjCSelectorName)
1413         Contexts.back().FirstObjCSelectorName->LongestObjCSelectorName =
1414             Contexts.back().LongestObjCSelectorName;
1415       return LT_ObjCMethodDecl;
1416     }
1417 
1418     for (const auto &ctx : Contexts)
1419       if (ctx.ContextType == Context::StructArrayInitializer)
1420         return LT_ArrayOfStructInitializer;
1421 
1422     return LT_Other;
1423   }
1424 
1425 private:
1426   bool isClosureImportStatement(const FormatToken &Tok) {
1427     // FIXME: Closure-library specific stuff should not be hard-coded but be
1428     // configurable.
1429     return Tok.TokenText == "goog" && Tok.Next && Tok.Next->is(tok::period) &&
1430            Tok.Next->Next &&
1431            (Tok.Next->Next->TokenText == "module" ||
1432             Tok.Next->Next->TokenText == "provide" ||
1433             Tok.Next->Next->TokenText == "require" ||
1434             Tok.Next->Next->TokenText == "requireType" ||
1435             Tok.Next->Next->TokenText == "forwardDeclare") &&
1436            Tok.Next->Next->Next && Tok.Next->Next->Next->is(tok::l_paren);
1437   }
1438 
1439   void resetTokenMetadata() {
1440     if (!CurrentToken)
1441       return;
1442 
1443     // Reset token type in case we have already looked at it and then
1444     // recovered from an error (e.g. failure to find the matching >).
1445     if (!CurrentToken->isTypeFinalized() &&
1446         !CurrentToken->isOneOf(
1447             TT_LambdaLSquare, TT_LambdaLBrace, TT_AttributeMacro, TT_IfMacro,
1448             TT_ForEachMacro, TT_TypenameMacro, TT_FunctionLBrace,
1449             TT_ImplicitStringLiteral, TT_InlineASMBrace, TT_FatArrow,
1450             TT_LambdaArrow, TT_NamespaceMacro, TT_OverloadedOperator,
1451             TT_RegexLiteral, TT_TemplateString, TT_ObjCStringLiteral,
1452             TT_UntouchableMacroFunc, TT_StatementAttributeLikeMacro,
1453             TT_FunctionLikeOrFreestandingMacro, TT_ClassLBrace, TT_EnumLBrace,
1454             TT_RecordLBrace, TT_StructLBrace, TT_UnionLBrace, TT_RequiresClause,
1455             TT_RequiresClauseInARequiresExpression, TT_RequiresExpression,
1456             TT_RequiresExpressionLParen, TT_RequiresExpressionLBrace,
1457             TT_CompoundRequirementLBrace, TT_BracedListLBrace))
1458       CurrentToken->setType(TT_Unknown);
1459     CurrentToken->Role.reset();
1460     CurrentToken->MatchingParen = nullptr;
1461     CurrentToken->FakeLParens.clear();
1462     CurrentToken->FakeRParens = 0;
1463   }
1464 
1465   void next() {
1466     if (!CurrentToken)
1467       return;
1468 
1469     CurrentToken->NestingLevel = Contexts.size() - 1;
1470     CurrentToken->BindingStrength = Contexts.back().BindingStrength;
1471     modifyContext(*CurrentToken);
1472     determineTokenType(*CurrentToken);
1473     CurrentToken = CurrentToken->Next;
1474 
1475     resetTokenMetadata();
1476   }
1477 
1478   /// A struct to hold information valid in a specific context, e.g.
1479   /// a pair of parenthesis.
1480   struct Context {
1481     Context(tok::TokenKind ContextKind, unsigned BindingStrength,
1482             bool IsExpression)
1483         : ContextKind(ContextKind), BindingStrength(BindingStrength),
1484           IsExpression(IsExpression) {}
1485 
1486     tok::TokenKind ContextKind;
1487     unsigned BindingStrength;
1488     bool IsExpression;
1489     unsigned LongestObjCSelectorName = 0;
1490     bool ColonIsForRangeExpr = false;
1491     bool ColonIsDictLiteral = false;
1492     bool ColonIsObjCMethodExpr = false;
1493     FormatToken *FirstObjCSelectorName = nullptr;
1494     FormatToken *FirstStartOfName = nullptr;
1495     bool CanBeExpression = true;
1496     bool CaretFound = false;
1497     bool InCpp11AttributeSpecifier = false;
1498     bool InCSharpAttributeSpecifier = false;
1499     enum {
1500       Unknown,
1501       // Like the part after `:` in a constructor.
1502       //   Context(...) : IsExpression(IsExpression)
1503       CtorInitializer,
1504       // Like in the parentheses in a foreach.
1505       ForEachMacro,
1506       // Like the inheritance list in a class declaration.
1507       //   class Input : public IO
1508       InheritanceList,
1509       // Like in the braced list.
1510       //   int x[] = {};
1511       StructArrayInitializer,
1512       // Like in `static_cast<int>`.
1513       TemplateArgument,
1514     } ContextType = Unknown;
1515   };
1516 
1517   /// Puts a new \c Context onto the stack \c Contexts for the lifetime
1518   /// of each instance.
1519   struct ScopedContextCreator {
1520     AnnotatingParser &P;
1521 
1522     ScopedContextCreator(AnnotatingParser &P, tok::TokenKind ContextKind,
1523                          unsigned Increase)
1524         : P(P) {
1525       P.Contexts.push_back(Context(ContextKind,
1526                                    P.Contexts.back().BindingStrength + Increase,
1527                                    P.Contexts.back().IsExpression));
1528     }
1529 
1530     ~ScopedContextCreator() {
1531       if (P.Style.AlignArrayOfStructures != FormatStyle::AIAS_None) {
1532         if (P.Contexts.back().ContextType == Context::StructArrayInitializer) {
1533           P.Contexts.pop_back();
1534           P.Contexts.back().ContextType = Context::StructArrayInitializer;
1535           return;
1536         }
1537       }
1538       P.Contexts.pop_back();
1539     }
1540   };
1541 
1542   void modifyContext(const FormatToken &Current) {
1543     auto AssignmentStartsExpression = [&]() {
1544       if (Current.getPrecedence() != prec::Assignment)
1545         return false;
1546 
1547       if (Line.First->isOneOf(tok::kw_using, tok::kw_return))
1548         return false;
1549       if (Line.First->is(tok::kw_template)) {
1550         assert(Current.Previous);
1551         if (Current.Previous->is(tok::kw_operator)) {
1552           // `template ... operator=` cannot be an expression.
1553           return false;
1554         }
1555 
1556         // `template` keyword can start a variable template.
1557         const FormatToken *Tok = Line.First->getNextNonComment();
1558         assert(Tok); // Current token is on the same line.
1559         if (Tok->isNot(TT_TemplateOpener)) {
1560           // Explicit template instantiations do not have `<>`.
1561           return false;
1562         }
1563 
1564         Tok = Tok->MatchingParen;
1565         if (!Tok)
1566           return false;
1567         Tok = Tok->getNextNonComment();
1568         if (!Tok)
1569           return false;
1570 
1571         if (Tok->isOneOf(tok::kw_class, tok::kw_enum, tok::kw_concept,
1572                          tok::kw_struct, tok::kw_using))
1573           return false;
1574 
1575         return true;
1576       }
1577 
1578       // Type aliases use `type X = ...;` in TypeScript and can be exported
1579       // using `export type ...`.
1580       if (Style.isJavaScript() &&
1581           (Line.startsWith(Keywords.kw_type, tok::identifier) ||
1582            Line.startsWith(tok::kw_export, Keywords.kw_type, tok::identifier)))
1583         return false;
1584 
1585       return !Current.Previous || Current.Previous->isNot(tok::kw_operator);
1586     };
1587 
1588     if (AssignmentStartsExpression()) {
1589       Contexts.back().IsExpression = true;
1590       if (!Line.startsWith(TT_UnaryOperator)) {
1591         for (FormatToken *Previous = Current.Previous;
1592              Previous && Previous->Previous &&
1593              !Previous->Previous->isOneOf(tok::comma, tok::semi);
1594              Previous = Previous->Previous) {
1595           if (Previous->isOneOf(tok::r_square, tok::r_paren)) {
1596             Previous = Previous->MatchingParen;
1597             if (!Previous)
1598               break;
1599           }
1600           if (Previous->opensScope())
1601             break;
1602           if (Previous->isOneOf(TT_BinaryOperator, TT_UnaryOperator) &&
1603               Previous->isOneOf(tok::star, tok::amp, tok::ampamp) &&
1604               Previous->Previous && Previous->Previous->isNot(tok::equal))
1605             Previous->setType(TT_PointerOrReference);
1606         }
1607       }
1608     } else if (Current.is(tok::lessless) &&
1609                (!Current.Previous || !Current.Previous->is(tok::kw_operator))) {
1610       Contexts.back().IsExpression = true;
1611     } else if (Current.isOneOf(tok::kw_return, tok::kw_throw)) {
1612       Contexts.back().IsExpression = true;
1613     } else if (Current.is(TT_TrailingReturnArrow)) {
1614       Contexts.back().IsExpression = false;
1615     } else if (Current.is(TT_LambdaArrow) || Current.is(Keywords.kw_assert)) {
1616       Contexts.back().IsExpression = Style.Language == FormatStyle::LK_Java;
1617     } else if (Current.Previous &&
1618                Current.Previous->is(TT_CtorInitializerColon)) {
1619       Contexts.back().IsExpression = true;
1620       Contexts.back().ContextType = Context::CtorInitializer;
1621     } else if (Current.Previous && Current.Previous->is(TT_InheritanceColon)) {
1622       Contexts.back().ContextType = Context::InheritanceList;
1623     } else if (Current.isOneOf(tok::r_paren, tok::greater, tok::comma)) {
1624       for (FormatToken *Previous = Current.Previous;
1625            Previous && Previous->isOneOf(tok::star, tok::amp);
1626            Previous = Previous->Previous)
1627         Previous->setType(TT_PointerOrReference);
1628       if (Line.MustBeDeclaration &&
1629           Contexts.front().ContextType != Context::CtorInitializer)
1630         Contexts.back().IsExpression = false;
1631     } else if (Current.is(tok::kw_new)) {
1632       Contexts.back().CanBeExpression = false;
1633     } else if (Current.is(tok::semi) ||
1634                (Current.is(tok::exclaim) && Current.Previous &&
1635                 !Current.Previous->is(tok::kw_operator))) {
1636       // This should be the condition or increment in a for-loop.
1637       // But not operator !() (can't use TT_OverloadedOperator here as its not
1638       // been annotated yet).
1639       Contexts.back().IsExpression = true;
1640     }
1641   }
1642 
1643   static FormatToken *untilMatchingParen(FormatToken *Current) {
1644     // Used when `MatchingParen` is not yet established.
1645     int ParenLevel = 0;
1646     while (Current) {
1647       if (Current->is(tok::l_paren))
1648         ++ParenLevel;
1649       if (Current->is(tok::r_paren))
1650         --ParenLevel;
1651       if (ParenLevel < 1)
1652         break;
1653       Current = Current->Next;
1654     }
1655     return Current;
1656   }
1657 
1658   static bool isDeductionGuide(FormatToken &Current) {
1659     // Look for a deduction guide template<T> A(...) -> A<...>;
1660     if (Current.Previous && Current.Previous->is(tok::r_paren) &&
1661         Current.startsSequence(tok::arrow, tok::identifier, tok::less)) {
1662       // Find the TemplateCloser.
1663       FormatToken *TemplateCloser = Current.Next->Next;
1664       int NestingLevel = 0;
1665       while (TemplateCloser) {
1666         // Skip over an expressions in parens  A<(3 < 2)>;
1667         if (TemplateCloser->is(tok::l_paren)) {
1668           // No Matching Paren yet so skip to matching paren
1669           TemplateCloser = untilMatchingParen(TemplateCloser);
1670           if (!TemplateCloser)
1671             break;
1672         }
1673         if (TemplateCloser->is(tok::less))
1674           ++NestingLevel;
1675         if (TemplateCloser->is(tok::greater))
1676           --NestingLevel;
1677         if (NestingLevel < 1)
1678           break;
1679         TemplateCloser = TemplateCloser->Next;
1680       }
1681       // Assuming we have found the end of the template ensure its followed
1682       // with a semi-colon.
1683       if (TemplateCloser && TemplateCloser->Next &&
1684           TemplateCloser->Next->is(tok::semi) &&
1685           Current.Previous->MatchingParen) {
1686         // Determine if the identifier `A` prior to the A<..>; is the same as
1687         // prior to the A(..)
1688         FormatToken *LeadingIdentifier =
1689             Current.Previous->MatchingParen->Previous;
1690 
1691         // Differentiate a deduction guide by seeing the
1692         // > of the template prior to the leading identifier.
1693         if (LeadingIdentifier) {
1694           FormatToken *PriorLeadingIdentifier = LeadingIdentifier->Previous;
1695           // Skip back past explicit decoration
1696           if (PriorLeadingIdentifier &&
1697               PriorLeadingIdentifier->is(tok::kw_explicit))
1698             PriorLeadingIdentifier = PriorLeadingIdentifier->Previous;
1699 
1700           return PriorLeadingIdentifier &&
1701                  (PriorLeadingIdentifier->is(TT_TemplateCloser) ||
1702                   PriorLeadingIdentifier->ClosesRequiresClause) &&
1703                  LeadingIdentifier->TokenText == Current.Next->TokenText;
1704         }
1705       }
1706     }
1707     return false;
1708   }
1709 
1710   void determineTokenType(FormatToken &Current) {
1711     if (!Current.is(TT_Unknown))
1712       // The token type is already known.
1713       return;
1714 
1715     if ((Style.isJavaScript() || Style.isCSharp()) &&
1716         Current.is(tok::exclaim)) {
1717       if (Current.Previous) {
1718         bool IsIdentifier =
1719             Style.isJavaScript()
1720                 ? Keywords.IsJavaScriptIdentifier(
1721                       *Current.Previous, /* AcceptIdentifierName= */ true)
1722                 : Current.Previous->is(tok::identifier);
1723         if (IsIdentifier ||
1724             Current.Previous->isOneOf(
1725                 tok::kw_default, tok::kw_namespace, tok::r_paren, tok::r_square,
1726                 tok::r_brace, tok::kw_false, tok::kw_true, Keywords.kw_type,
1727                 Keywords.kw_get, Keywords.kw_init, Keywords.kw_set) ||
1728             Current.Previous->Tok.isLiteral()) {
1729           Current.setType(TT_NonNullAssertion);
1730           return;
1731         }
1732       }
1733       if (Current.Next &&
1734           Current.Next->isOneOf(TT_BinaryOperator, Keywords.kw_as)) {
1735         Current.setType(TT_NonNullAssertion);
1736         return;
1737       }
1738     }
1739 
1740     // Line.MightBeFunctionDecl can only be true after the parentheses of a
1741     // function declaration have been found. In this case, 'Current' is a
1742     // trailing token of this declaration and thus cannot be a name.
1743     if (Current.is(Keywords.kw_instanceof)) {
1744       Current.setType(TT_BinaryOperator);
1745     } else if (isStartOfName(Current) &&
1746                (!Line.MightBeFunctionDecl || Current.NestingLevel != 0)) {
1747       Contexts.back().FirstStartOfName = &Current;
1748       Current.setType(TT_StartOfName);
1749     } else if (Current.is(tok::semi)) {
1750       // Reset FirstStartOfName after finding a semicolon so that a for loop
1751       // with multiple increment statements is not confused with a for loop
1752       // having multiple variable declarations.
1753       Contexts.back().FirstStartOfName = nullptr;
1754     } else if (Current.isOneOf(tok::kw_auto, tok::kw___auto_type)) {
1755       AutoFound = true;
1756     } else if (Current.is(tok::arrow) &&
1757                Style.Language == FormatStyle::LK_Java) {
1758       Current.setType(TT_LambdaArrow);
1759     } else if (Current.is(tok::arrow) && AutoFound && Line.MustBeDeclaration &&
1760                Current.NestingLevel == 0 &&
1761                !Current.Previous->isOneOf(tok::kw_operator, tok::identifier)) {
1762       // not auto operator->() -> xxx;
1763       Current.setType(TT_TrailingReturnArrow);
1764     } else if (Current.is(tok::arrow) && Current.Previous &&
1765                Current.Previous->is(tok::r_brace)) {
1766       // Concept implicit conversion constraint needs to be treated like
1767       // a trailing return type  ... } -> <type>.
1768       Current.setType(TT_TrailingReturnArrow);
1769     } else if (isDeductionGuide(Current)) {
1770       // Deduction guides trailing arrow " A(...) -> A<T>;".
1771       Current.setType(TT_TrailingReturnArrow);
1772     } else if (Current.isOneOf(tok::star, tok::amp, tok::ampamp)) {
1773       Current.setType(determineStarAmpUsage(
1774           Current,
1775           Contexts.back().CanBeExpression && Contexts.back().IsExpression,
1776           Contexts.back().ContextType == Context::TemplateArgument));
1777     } else if (Current.isOneOf(tok::minus, tok::plus, tok::caret)) {
1778       Current.setType(determinePlusMinusCaretUsage(Current));
1779       if (Current.is(TT_UnaryOperator) && Current.is(tok::caret))
1780         Contexts.back().CaretFound = true;
1781     } else if (Current.isOneOf(tok::minusminus, tok::plusplus)) {
1782       Current.setType(determineIncrementUsage(Current));
1783     } else if (Current.isOneOf(tok::exclaim, tok::tilde)) {
1784       Current.setType(TT_UnaryOperator);
1785     } else if (Current.is(tok::question)) {
1786       if (Style.isJavaScript() && Line.MustBeDeclaration &&
1787           !Contexts.back().IsExpression) {
1788         // In JavaScript, `interface X { foo?(): bar; }` is an optional method
1789         // on the interface, not a ternary expression.
1790         Current.setType(TT_JsTypeOptionalQuestion);
1791       } else {
1792         Current.setType(TT_ConditionalExpr);
1793       }
1794     } else if (Current.isBinaryOperator() &&
1795                (!Current.Previous || Current.Previous->isNot(tok::l_square)) &&
1796                (!Current.is(tok::greater) &&
1797                 Style.Language != FormatStyle::LK_TextProto)) {
1798       Current.setType(TT_BinaryOperator);
1799     } else if (Current.is(tok::comment)) {
1800       if (Current.TokenText.startswith("/*"))
1801         if (Current.TokenText.endswith("*/"))
1802           Current.setType(TT_BlockComment);
1803         else
1804           // The lexer has for some reason determined a comment here. But we
1805           // cannot really handle it, if it isn't properly terminated.
1806           Current.Tok.setKind(tok::unknown);
1807       else
1808         Current.setType(TT_LineComment);
1809     } else if (Current.is(tok::l_paren)) {
1810       if (lParenStartsCppCast(Current))
1811         Current.setType(TT_CppCastLParen);
1812     } else if (Current.is(tok::r_paren)) {
1813       if (rParenEndsCast(Current))
1814         Current.setType(TT_CastRParen);
1815       if (Current.MatchingParen && Current.Next &&
1816           !Current.Next->isBinaryOperator() &&
1817           !Current.Next->isOneOf(tok::semi, tok::colon, tok::l_brace,
1818                                  tok::comma, tok::period, tok::arrow,
1819                                  tok::coloncolon))
1820         if (FormatToken *AfterParen = Current.MatchingParen->Next) {
1821           // Make sure this isn't the return type of an Obj-C block declaration
1822           if (AfterParen->isNot(tok::caret)) {
1823             if (FormatToken *BeforeParen = Current.MatchingParen->Previous)
1824               if (BeforeParen->is(tok::identifier) &&
1825                   !BeforeParen->is(TT_TypenameMacro) &&
1826                   BeforeParen->TokenText == BeforeParen->TokenText.upper() &&
1827                   (!BeforeParen->Previous ||
1828                    BeforeParen->Previous->ClosesTemplateDeclaration))
1829                 Current.setType(TT_FunctionAnnotationRParen);
1830           }
1831         }
1832     } else if (Current.is(tok::at) && Current.Next && !Style.isJavaScript() &&
1833                Style.Language != FormatStyle::LK_Java) {
1834       // In Java & JavaScript, "@..." is a decorator or annotation. In ObjC, it
1835       // marks declarations and properties that need special formatting.
1836       switch (Current.Next->Tok.getObjCKeywordID()) {
1837       case tok::objc_interface:
1838       case tok::objc_implementation:
1839       case tok::objc_protocol:
1840         Current.setType(TT_ObjCDecl);
1841         break;
1842       case tok::objc_property:
1843         Current.setType(TT_ObjCProperty);
1844         break;
1845       default:
1846         break;
1847       }
1848     } else if (Current.is(tok::period)) {
1849       FormatToken *PreviousNoComment = Current.getPreviousNonComment();
1850       if (PreviousNoComment &&
1851           PreviousNoComment->isOneOf(tok::comma, tok::l_brace))
1852         Current.setType(TT_DesignatedInitializerPeriod);
1853       else if (Style.Language == FormatStyle::LK_Java && Current.Previous &&
1854                Current.Previous->isOneOf(TT_JavaAnnotation,
1855                                          TT_LeadingJavaAnnotation))
1856         Current.setType(Current.Previous->getType());
1857     } else if (canBeObjCSelectorComponent(Current) &&
1858                // FIXME(bug 36976): ObjC return types shouldn't use
1859                // TT_CastRParen.
1860                Current.Previous && Current.Previous->is(TT_CastRParen) &&
1861                Current.Previous->MatchingParen &&
1862                Current.Previous->MatchingParen->Previous &&
1863                Current.Previous->MatchingParen->Previous->is(
1864                    TT_ObjCMethodSpecifier)) {
1865       // This is the first part of an Objective-C selector name. (If there's no
1866       // colon after this, this is the only place which annotates the identifier
1867       // as a selector.)
1868       Current.setType(TT_SelectorName);
1869     } else if (Current.isOneOf(tok::identifier, tok::kw_const, tok::kw_noexcept,
1870                                tok::kw_requires) &&
1871                Current.Previous &&
1872                !Current.Previous->isOneOf(tok::equal, tok::at) &&
1873                Line.MightBeFunctionDecl && Contexts.size() == 1) {
1874       // Line.MightBeFunctionDecl can only be true after the parentheses of a
1875       // function declaration have been found.
1876       Current.setType(TT_TrailingAnnotation);
1877     } else if ((Style.Language == FormatStyle::LK_Java ||
1878                 Style.isJavaScript()) &&
1879                Current.Previous) {
1880       if (Current.Previous->is(tok::at) &&
1881           Current.isNot(Keywords.kw_interface)) {
1882         const FormatToken &AtToken = *Current.Previous;
1883         const FormatToken *Previous = AtToken.getPreviousNonComment();
1884         if (!Previous || Previous->is(TT_LeadingJavaAnnotation))
1885           Current.setType(TT_LeadingJavaAnnotation);
1886         else
1887           Current.setType(TT_JavaAnnotation);
1888       } else if (Current.Previous->is(tok::period) &&
1889                  Current.Previous->isOneOf(TT_JavaAnnotation,
1890                                            TT_LeadingJavaAnnotation)) {
1891         Current.setType(Current.Previous->getType());
1892       }
1893     }
1894   }
1895 
1896   /// Take a guess at whether \p Tok starts a name of a function or
1897   /// variable declaration.
1898   ///
1899   /// This is a heuristic based on whether \p Tok is an identifier following
1900   /// something that is likely a type.
1901   bool isStartOfName(const FormatToken &Tok) {
1902     if (Tok.isNot(tok::identifier) || !Tok.Previous)
1903       return false;
1904 
1905     if (Tok.Previous->isOneOf(TT_LeadingJavaAnnotation, Keywords.kw_instanceof,
1906                               Keywords.kw_as))
1907       return false;
1908     if (Style.isJavaScript() && Tok.Previous->is(Keywords.kw_in))
1909       return false;
1910 
1911     // Skip "const" as it does not have an influence on whether this is a name.
1912     FormatToken *PreviousNotConst = Tok.getPreviousNonComment();
1913 
1914     // For javascript const can be like "let" or "var"
1915     if (!Style.isJavaScript())
1916       while (PreviousNotConst && PreviousNotConst->is(tok::kw_const))
1917         PreviousNotConst = PreviousNotConst->getPreviousNonComment();
1918 
1919     if (!PreviousNotConst)
1920       return false;
1921 
1922     if (PreviousNotConst->ClosesRequiresClause)
1923       return false;
1924 
1925     bool IsPPKeyword = PreviousNotConst->is(tok::identifier) &&
1926                        PreviousNotConst->Previous &&
1927                        PreviousNotConst->Previous->is(tok::hash);
1928 
1929     if (PreviousNotConst->is(TT_TemplateCloser))
1930       return PreviousNotConst && PreviousNotConst->MatchingParen &&
1931              PreviousNotConst->MatchingParen->Previous &&
1932              PreviousNotConst->MatchingParen->Previous->isNot(tok::period) &&
1933              PreviousNotConst->MatchingParen->Previous->isNot(tok::kw_template);
1934 
1935     if (PreviousNotConst->is(tok::r_paren) &&
1936         PreviousNotConst->is(TT_TypeDeclarationParen))
1937       return true;
1938 
1939     // If is a preprocess keyword like #define.
1940     if (IsPPKeyword)
1941       return false;
1942 
1943     // int a or auto a.
1944     if (PreviousNotConst->isOneOf(tok::identifier, tok::kw_auto))
1945       return true;
1946 
1947     // *a or &a or &&a.
1948     if (PreviousNotConst->is(TT_PointerOrReference))
1949       return true;
1950 
1951     // MyClass a;
1952     if (PreviousNotConst->isSimpleTypeSpecifier())
1953       return true;
1954 
1955     // const a = in JavaScript.
1956     return Style.isJavaScript() && PreviousNotConst->is(tok::kw_const);
1957   }
1958 
1959   /// Determine whether '(' is starting a C++ cast.
1960   bool lParenStartsCppCast(const FormatToken &Tok) {
1961     // C-style casts are only used in C++.
1962     if (!Style.isCpp())
1963       return false;
1964 
1965     FormatToken *LeftOfParens = Tok.getPreviousNonComment();
1966     if (LeftOfParens && LeftOfParens->is(TT_TemplateCloser) &&
1967         LeftOfParens->MatchingParen) {
1968       auto *Prev = LeftOfParens->MatchingParen->getPreviousNonComment();
1969       if (Prev && Prev->isOneOf(tok::kw_const_cast, tok::kw_dynamic_cast,
1970                                 tok::kw_reinterpret_cast, tok::kw_static_cast))
1971         // FIXME: Maybe we should handle identifiers ending with "_cast",
1972         // e.g. any_cast?
1973         return true;
1974     }
1975     return false;
1976   }
1977 
1978   /// Determine whether ')' is ending a cast.
1979   bool rParenEndsCast(const FormatToken &Tok) {
1980     // C-style casts are only used in C++, C# and Java.
1981     if (!Style.isCSharp() && !Style.isCpp() &&
1982         Style.Language != FormatStyle::LK_Java)
1983       return false;
1984 
1985     // Empty parens aren't casts and there are no casts at the end of the line.
1986     if (Tok.Previous == Tok.MatchingParen || !Tok.Next || !Tok.MatchingParen)
1987       return false;
1988 
1989     FormatToken *LeftOfParens = Tok.MatchingParen->getPreviousNonComment();
1990     if (LeftOfParens) {
1991       // If there is a closing parenthesis left of the current
1992       // parentheses, look past it as these might be chained casts.
1993       if (LeftOfParens->is(tok::r_paren) &&
1994           LeftOfParens->isNot(TT_CastRParen)) {
1995         if (!LeftOfParens->MatchingParen ||
1996             !LeftOfParens->MatchingParen->Previous)
1997           return false;
1998         LeftOfParens = LeftOfParens->MatchingParen->Previous;
1999       }
2000 
2001       if (LeftOfParens->is(tok::r_square)) {
2002         //   delete[] (void *)ptr;
2003         auto MayBeArrayDelete = [](FormatToken *Tok) -> FormatToken * {
2004           if (Tok->isNot(tok::r_square))
2005             return nullptr;
2006 
2007           Tok = Tok->getPreviousNonComment();
2008           if (!Tok || Tok->isNot(tok::l_square))
2009             return nullptr;
2010 
2011           Tok = Tok->getPreviousNonComment();
2012           if (!Tok || Tok->isNot(tok::kw_delete))
2013             return nullptr;
2014           return Tok;
2015         };
2016         if (FormatToken *MaybeDelete = MayBeArrayDelete(LeftOfParens))
2017           LeftOfParens = MaybeDelete;
2018       }
2019 
2020       // The Condition directly below this one will see the operator arguments
2021       // as a (void *foo) cast.
2022       //   void operator delete(void *foo) ATTRIB;
2023       if (LeftOfParens->Tok.getIdentifierInfo() && LeftOfParens->Previous &&
2024           LeftOfParens->Previous->is(tok::kw_operator))
2025         return false;
2026 
2027       // If there is an identifier (or with a few exceptions a keyword) right
2028       // before the parentheses, this is unlikely to be a cast.
2029       if (LeftOfParens->Tok.getIdentifierInfo() &&
2030           !LeftOfParens->isOneOf(Keywords.kw_in, tok::kw_return, tok::kw_case,
2031                                  tok::kw_delete))
2032         return false;
2033 
2034       // Certain other tokens right before the parentheses are also signals that
2035       // this cannot be a cast.
2036       if (LeftOfParens->isOneOf(tok::at, tok::r_square, TT_OverloadedOperator,
2037                                 TT_TemplateCloser, tok::ellipsis))
2038         return false;
2039     }
2040 
2041     if (Tok.Next->is(tok::question))
2042       return false;
2043 
2044     // `foreach((A a, B b) in someList)` should not be seen as a cast.
2045     if (Tok.Next->is(Keywords.kw_in) && Style.isCSharp())
2046       return false;
2047 
2048     // Functions which end with decorations like volatile, noexcept are unlikely
2049     // to be casts.
2050     if (Tok.Next->isOneOf(tok::kw_noexcept, tok::kw_volatile, tok::kw_const,
2051                           tok::kw_requires, tok::kw_throw, tok::arrow,
2052                           Keywords.kw_override, Keywords.kw_final) ||
2053         isCpp11AttributeSpecifier(*Tok.Next))
2054       return false;
2055 
2056     // As Java has no function types, a "(" after the ")" likely means that this
2057     // is a cast.
2058     if (Style.Language == FormatStyle::LK_Java && Tok.Next->is(tok::l_paren))
2059       return true;
2060 
2061     // If a (non-string) literal follows, this is likely a cast.
2062     if (Tok.Next->isNot(tok::string_literal) &&
2063         (Tok.Next->Tok.isLiteral() ||
2064          Tok.Next->isOneOf(tok::kw_sizeof, tok::kw_alignof)))
2065       return true;
2066 
2067     // Heuristically try to determine whether the parentheses contain a type.
2068     auto IsQualifiedPointerOrReference = [](FormatToken *T) {
2069       // This is used to handle cases such as x = (foo *const)&y;
2070       assert(!T->isSimpleTypeSpecifier() && "Should have already been checked");
2071       // Strip trailing qualifiers such as const or volatile when checking
2072       // whether the parens could be a cast to a pointer/reference type.
2073       while (T) {
2074         if (T->is(TT_AttributeParen)) {
2075           // Handle `x = (foo *__attribute__((foo)))&v;`:
2076           if (T->MatchingParen && T->MatchingParen->Previous &&
2077               T->MatchingParen->Previous->is(tok::kw___attribute)) {
2078             T = T->MatchingParen->Previous->Previous;
2079             continue;
2080           }
2081         } else if (T->is(TT_AttributeSquare)) {
2082           // Handle `x = (foo *[[clang::foo]])&v;`:
2083           if (T->MatchingParen && T->MatchingParen->Previous) {
2084             T = T->MatchingParen->Previous;
2085             continue;
2086           }
2087         } else if (T->canBePointerOrReferenceQualifier()) {
2088           T = T->Previous;
2089           continue;
2090         }
2091         break;
2092       }
2093       return T && T->is(TT_PointerOrReference);
2094     };
2095     bool ParensAreType =
2096         !Tok.Previous ||
2097         Tok.Previous->isOneOf(TT_TemplateCloser, TT_TypeDeclarationParen) ||
2098         Tok.Previous->isSimpleTypeSpecifier() ||
2099         IsQualifiedPointerOrReference(Tok.Previous);
2100     bool ParensCouldEndDecl =
2101         Tok.Next->isOneOf(tok::equal, tok::semi, tok::l_brace, tok::greater);
2102     if (ParensAreType && !ParensCouldEndDecl)
2103       return true;
2104 
2105     // At this point, we heuristically assume that there are no casts at the
2106     // start of the line. We assume that we have found most cases where there
2107     // are by the logic above, e.g. "(void)x;".
2108     if (!LeftOfParens)
2109       return false;
2110 
2111     // Certain token types inside the parentheses mean that this can't be a
2112     // cast.
2113     for (const FormatToken *Token = Tok.MatchingParen->Next; Token != &Tok;
2114          Token = Token->Next)
2115       if (Token->is(TT_BinaryOperator))
2116         return false;
2117 
2118     // If the following token is an identifier or 'this', this is a cast. All
2119     // cases where this can be something else are handled above.
2120     if (Tok.Next->isOneOf(tok::identifier, tok::kw_this))
2121       return true;
2122 
2123     // Look for a cast `( x ) (`.
2124     if (Tok.Next->is(tok::l_paren) && Tok.Previous && Tok.Previous->Previous) {
2125       if (Tok.Previous->is(tok::identifier) &&
2126           Tok.Previous->Previous->is(tok::l_paren))
2127         return true;
2128     }
2129 
2130     if (!Tok.Next->Next)
2131       return false;
2132 
2133     // If the next token after the parenthesis is a unary operator, assume
2134     // that this is cast, unless there are unexpected tokens inside the
2135     // parenthesis.
2136     bool NextIsUnary =
2137         Tok.Next->isUnaryOperator() || Tok.Next->isOneOf(tok::amp, tok::star);
2138     if (!NextIsUnary || Tok.Next->is(tok::plus) ||
2139         !Tok.Next->Next->isOneOf(tok::identifier, tok::numeric_constant))
2140       return false;
2141     // Search for unexpected tokens.
2142     for (FormatToken *Prev = Tok.Previous; Prev != Tok.MatchingParen;
2143          Prev = Prev->Previous)
2144       if (!Prev->isOneOf(tok::kw_const, tok::identifier, tok::coloncolon))
2145         return false;
2146     return true;
2147   }
2148 
2149   /// Return the type of the given token assuming it is * or &.
2150   TokenType determineStarAmpUsage(const FormatToken &Tok, bool IsExpression,
2151                                   bool InTemplateArgument) {
2152     if (Style.isJavaScript())
2153       return TT_BinaryOperator;
2154 
2155     // && in C# must be a binary operator.
2156     if (Style.isCSharp() && Tok.is(tok::ampamp))
2157       return TT_BinaryOperator;
2158 
2159     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2160     if (!PrevToken)
2161       return TT_UnaryOperator;
2162 
2163     const FormatToken *NextToken = Tok.getNextNonComment();
2164 
2165     if (InTemplateArgument && NextToken && NextToken->is(tok::kw_noexcept))
2166       return TT_BinaryOperator;
2167 
2168     if (!NextToken ||
2169         NextToken->isOneOf(tok::arrow, tok::equal, tok::kw_noexcept) ||
2170         NextToken->canBePointerOrReferenceQualifier() ||
2171         (NextToken->is(tok::l_brace) && !NextToken->getNextNonComment()))
2172       return TT_PointerOrReference;
2173 
2174     if (PrevToken->is(tok::coloncolon))
2175       return TT_PointerOrReference;
2176 
2177     if (PrevToken->is(tok::r_paren) && PrevToken->is(TT_TypeDeclarationParen))
2178       return TT_PointerOrReference;
2179 
2180     if (PrevToken->isOneOf(tok::l_paren, tok::l_square, tok::l_brace,
2181                            tok::comma, tok::semi, tok::kw_return, tok::colon,
2182                            tok::kw_co_return, tok::kw_co_await,
2183                            tok::kw_co_yield, tok::equal, tok::kw_delete,
2184                            tok::kw_sizeof, tok::kw_throw, TT_BinaryOperator,
2185                            TT_ConditionalExpr, TT_UnaryOperator, TT_CastRParen))
2186       return TT_UnaryOperator;
2187 
2188     if (NextToken->is(tok::l_square) && NextToken->isNot(TT_LambdaLSquare))
2189       return TT_PointerOrReference;
2190     if (NextToken->is(tok::kw_operator) && !IsExpression)
2191       return TT_PointerOrReference;
2192     if (NextToken->isOneOf(tok::comma, tok::semi))
2193       return TT_PointerOrReference;
2194 
2195     if (PrevToken->Tok.isLiteral() ||
2196         PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::kw_true,
2197                            tok::kw_false, tok::r_brace))
2198       return TT_BinaryOperator;
2199 
2200     const FormatToken *NextNonParen = NextToken;
2201     while (NextNonParen && NextNonParen->is(tok::l_paren))
2202       NextNonParen = NextNonParen->getNextNonComment();
2203     if (NextNonParen && (NextNonParen->Tok.isLiteral() ||
2204                          NextNonParen->isOneOf(tok::kw_true, tok::kw_false) ||
2205                          NextNonParen->isUnaryOperator()))
2206       return TT_BinaryOperator;
2207 
2208     // If we know we're in a template argument, there are no named declarations.
2209     // Thus, having an identifier on the right-hand side indicates a binary
2210     // operator.
2211     if (InTemplateArgument && NextToken->Tok.isAnyIdentifier())
2212       return TT_BinaryOperator;
2213 
2214     // "&&(" is quite unlikely to be two successive unary "&".
2215     if (Tok.is(tok::ampamp) && NextToken->is(tok::l_paren))
2216       return TT_BinaryOperator;
2217 
2218     // This catches some cases where evaluation order is used as control flow:
2219     //   aaa && aaa->f();
2220     if (NextToken->Tok.isAnyIdentifier()) {
2221       const FormatToken *NextNextToken = NextToken->getNextNonComment();
2222       if (NextNextToken && NextNextToken->is(tok::arrow))
2223         return TT_BinaryOperator;
2224     }
2225 
2226     // It is very unlikely that we are going to find a pointer or reference type
2227     // definition on the RHS of an assignment.
2228     if (IsExpression && !Contexts.back().CaretFound)
2229       return TT_BinaryOperator;
2230 
2231     return TT_PointerOrReference;
2232   }
2233 
2234   TokenType determinePlusMinusCaretUsage(const FormatToken &Tok) {
2235     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2236     if (!PrevToken)
2237       return TT_UnaryOperator;
2238 
2239     if (PrevToken->isOneOf(TT_CastRParen, TT_UnaryOperator))
2240       // This must be a sequence of leading unary operators.
2241       return TT_UnaryOperator;
2242 
2243     // Use heuristics to recognize unary operators.
2244     if (PrevToken->isOneOf(tok::equal, tok::l_paren, tok::comma, tok::l_square,
2245                            tok::question, tok::colon, tok::kw_return,
2246                            tok::kw_case, tok::at, tok::l_brace, tok::kw_throw,
2247                            tok::kw_co_return, tok::kw_co_yield))
2248       return TT_UnaryOperator;
2249 
2250     // There can't be two consecutive binary operators.
2251     if (PrevToken->is(TT_BinaryOperator))
2252       return TT_UnaryOperator;
2253 
2254     // Fall back to marking the token as binary operator.
2255     return TT_BinaryOperator;
2256   }
2257 
2258   /// Determine whether ++/-- are pre- or post-increments/-decrements.
2259   TokenType determineIncrementUsage(const FormatToken &Tok) {
2260     const FormatToken *PrevToken = Tok.getPreviousNonComment();
2261     if (!PrevToken || PrevToken->is(TT_CastRParen))
2262       return TT_UnaryOperator;
2263     if (PrevToken->isOneOf(tok::r_paren, tok::r_square, tok::identifier))
2264       return TT_TrailingUnaryOperator;
2265 
2266     return TT_UnaryOperator;
2267   }
2268 
2269   SmallVector<Context, 8> Contexts;
2270 
2271   const FormatStyle &Style;
2272   AnnotatedLine &Line;
2273   FormatToken *CurrentToken;
2274   bool AutoFound;
2275   const AdditionalKeywords &Keywords;
2276 
2277   // Set of "<" tokens that do not open a template parameter list. If parseAngle
2278   // determines that a specific token can't be a template opener, it will make
2279   // same decision irrespective of the decisions for tokens leading up to it.
2280   // Store this information to prevent this from causing exponential runtime.
2281   llvm::SmallPtrSet<FormatToken *, 16> NonTemplateLess;
2282 };
2283 
2284 static const int PrecedenceUnaryOperator = prec::PointerToMember + 1;
2285 static const int PrecedenceArrowAndPeriod = prec::PointerToMember + 2;
2286 
2287 /// Parses binary expressions by inserting fake parenthesis based on
2288 /// operator precedence.
2289 class ExpressionParser {
2290 public:
2291   ExpressionParser(const FormatStyle &Style, const AdditionalKeywords &Keywords,
2292                    AnnotatedLine &Line)
2293       : Style(Style), Keywords(Keywords), Line(Line), Current(Line.First) {}
2294 
2295   /// Parse expressions with the given operator precedence.
2296   void parse(int Precedence = 0) {
2297     // Skip 'return' and ObjC selector colons as they are not part of a binary
2298     // expression.
2299     while (Current && (Current->is(tok::kw_return) ||
2300                        (Current->is(tok::colon) &&
2301                         Current->isOneOf(TT_ObjCMethodExpr, TT_DictLiteral))))
2302       next();
2303 
2304     if (!Current || Precedence > PrecedenceArrowAndPeriod)
2305       return;
2306 
2307     // Conditional expressions need to be parsed separately for proper nesting.
2308     if (Precedence == prec::Conditional) {
2309       parseConditionalExpr();
2310       return;
2311     }
2312 
2313     // Parse unary operators, which all have a higher precedence than binary
2314     // operators.
2315     if (Precedence == PrecedenceUnaryOperator) {
2316       parseUnaryOperator();
2317       return;
2318     }
2319 
2320     FormatToken *Start = Current;
2321     FormatToken *LatestOperator = nullptr;
2322     unsigned OperatorIndex = 0;
2323 
2324     while (Current) {
2325       // Consume operators with higher precedence.
2326       parse(Precedence + 1);
2327 
2328       int CurrentPrecedence = getCurrentPrecedence();
2329 
2330       if (Precedence == CurrentPrecedence && Current &&
2331           Current->is(TT_SelectorName)) {
2332         if (LatestOperator)
2333           addFakeParenthesis(Start, prec::Level(Precedence));
2334         Start = Current;
2335       }
2336 
2337       // At the end of the line or when an operator with higher precedence is
2338       // found, insert fake parenthesis and return.
2339       if (!Current ||
2340           (Current->closesScope() &&
2341            (Current->MatchingParen || Current->is(TT_TemplateString))) ||
2342           (CurrentPrecedence != -1 && CurrentPrecedence < Precedence) ||
2343           (CurrentPrecedence == prec::Conditional &&
2344            Precedence == prec::Assignment && Current->is(tok::colon)))
2345         break;
2346 
2347       // Consume scopes: (), [], <> and {}
2348       // In addition to that we handle require clauses as scope, so that the
2349       // constraints in that are correctly indented.
2350       if (Current->opensScope() ||
2351           Current->isOneOf(TT_RequiresClause,
2352                            TT_RequiresClauseInARequiresExpression)) {
2353         // In fragment of a JavaScript template string can look like '}..${' and
2354         // thus close a scope and open a new one at the same time.
2355         while (Current && (!Current->closesScope() || Current->opensScope())) {
2356           next();
2357           parse();
2358         }
2359         next();
2360       } else {
2361         // Operator found.
2362         if (CurrentPrecedence == Precedence) {
2363           if (LatestOperator)
2364             LatestOperator->NextOperator = Current;
2365           LatestOperator = Current;
2366           Current->OperatorIndex = OperatorIndex;
2367           ++OperatorIndex;
2368         }
2369         next(/*SkipPastLeadingComments=*/Precedence > 0);
2370       }
2371     }
2372 
2373     if (LatestOperator && (Current || Precedence > 0)) {
2374       // The requires clauses do not neccessarily end in a semicolon or a brace,
2375       // but just go over to struct/class or a function declaration, we need to
2376       // intervene so that the fake right paren is inserted correctly.
2377       auto End =
2378           (Start->Previous &&
2379            Start->Previous->isOneOf(TT_RequiresClause,
2380                                     TT_RequiresClauseInARequiresExpression))
2381               ? [this](){
2382                   auto Ret = Current ? Current : Line.Last;
2383                   while (!Ret->ClosesRequiresClause && Ret->Previous)
2384                     Ret = Ret->Previous;
2385                   return Ret;
2386                 }()
2387               : nullptr;
2388 
2389       if (Precedence == PrecedenceArrowAndPeriod) {
2390         // Call expressions don't have a binary operator precedence.
2391         addFakeParenthesis(Start, prec::Unknown, End);
2392       } else {
2393         addFakeParenthesis(Start, prec::Level(Precedence), End);
2394       }
2395     }
2396   }
2397 
2398 private:
2399   /// Gets the precedence (+1) of the given token for binary operators
2400   /// and other tokens that we treat like binary operators.
2401   int getCurrentPrecedence() {
2402     if (Current) {
2403       const FormatToken *NextNonComment = Current->getNextNonComment();
2404       if (Current->is(TT_ConditionalExpr))
2405         return prec::Conditional;
2406       if (NextNonComment && Current->is(TT_SelectorName) &&
2407           (NextNonComment->isOneOf(TT_DictLiteral, TT_JsTypeColon) ||
2408            ((Style.Language == FormatStyle::LK_Proto ||
2409              Style.Language == FormatStyle::LK_TextProto) &&
2410             NextNonComment->is(tok::less))))
2411         return prec::Assignment;
2412       if (Current->is(TT_JsComputedPropertyName))
2413         return prec::Assignment;
2414       if (Current->is(TT_LambdaArrow))
2415         return prec::Comma;
2416       if (Current->is(TT_FatArrow))
2417         return prec::Assignment;
2418       if (Current->isOneOf(tok::semi, TT_InlineASMColon, TT_SelectorName) ||
2419           (Current->is(tok::comment) && NextNonComment &&
2420            NextNonComment->is(TT_SelectorName)))
2421         return 0;
2422       if (Current->is(TT_RangeBasedForLoopColon))
2423         return prec::Comma;
2424       if ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
2425           Current->is(Keywords.kw_instanceof))
2426         return prec::Relational;
2427       if (Style.isJavaScript() &&
2428           Current->isOneOf(Keywords.kw_in, Keywords.kw_as))
2429         return prec::Relational;
2430       if (Current->is(TT_BinaryOperator) || Current->is(tok::comma))
2431         return Current->getPrecedence();
2432       if (Current->isOneOf(tok::period, tok::arrow))
2433         return PrecedenceArrowAndPeriod;
2434       if ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
2435           Current->isOneOf(Keywords.kw_extends, Keywords.kw_implements,
2436                            Keywords.kw_throws))
2437         return 0;
2438     }
2439     return -1;
2440   }
2441 
2442   void addFakeParenthesis(FormatToken *Start, prec::Level Precedence,
2443                           FormatToken *End = nullptr) {
2444     Start->FakeLParens.push_back(Precedence);
2445     if (Precedence > prec::Unknown)
2446       Start->StartsBinaryExpression = true;
2447     if (!End && Current)
2448       End = Current->getPreviousNonComment();
2449     if (End) {
2450       ++End->FakeRParens;
2451       if (Precedence > prec::Unknown)
2452         End->EndsBinaryExpression = true;
2453     }
2454   }
2455 
2456   /// Parse unary operator expressions and surround them with fake
2457   /// parentheses if appropriate.
2458   void parseUnaryOperator() {
2459     llvm::SmallVector<FormatToken *, 2> Tokens;
2460     while (Current && Current->is(TT_UnaryOperator)) {
2461       Tokens.push_back(Current);
2462       next();
2463     }
2464     parse(PrecedenceArrowAndPeriod);
2465     for (FormatToken *Token : llvm::reverse(Tokens))
2466       // The actual precedence doesn't matter.
2467       addFakeParenthesis(Token, prec::Unknown);
2468   }
2469 
2470   void parseConditionalExpr() {
2471     while (Current && Current->isTrailingComment())
2472       next();
2473     FormatToken *Start = Current;
2474     parse(prec::LogicalOr);
2475     if (!Current || !Current->is(tok::question))
2476       return;
2477     next();
2478     parse(prec::Assignment);
2479     if (!Current || Current->isNot(TT_ConditionalExpr))
2480       return;
2481     next();
2482     parse(prec::Assignment);
2483     addFakeParenthesis(Start, prec::Conditional);
2484   }
2485 
2486   void next(bool SkipPastLeadingComments = true) {
2487     if (Current)
2488       Current = Current->Next;
2489     while (Current &&
2490            (Current->NewlinesBefore == 0 || SkipPastLeadingComments) &&
2491            Current->isTrailingComment())
2492       Current = Current->Next;
2493   }
2494 
2495   const FormatStyle &Style;
2496   const AdditionalKeywords &Keywords;
2497   const AnnotatedLine &Line;
2498   FormatToken *Current;
2499 };
2500 
2501 } // end anonymous namespace
2502 
2503 void TokenAnnotator::setCommentLineLevels(
2504     SmallVectorImpl<AnnotatedLine *> &Lines) {
2505   const AnnotatedLine *NextNonCommentLine = nullptr;
2506   for (AnnotatedLine *Line : llvm::reverse(Lines)) {
2507     assert(Line->First);
2508     bool CommentLine = true;
2509     for (const FormatToken *Tok = Line->First; Tok; Tok = Tok->Next) {
2510       if (!Tok->is(tok::comment)) {
2511         CommentLine = false;
2512         break;
2513       }
2514     }
2515 
2516     // If the comment is currently aligned with the line immediately following
2517     // it, that's probably intentional and we should keep it.
2518     if (NextNonCommentLine && CommentLine &&
2519         NextNonCommentLine->First->NewlinesBefore <= 1 &&
2520         NextNonCommentLine->First->OriginalColumn ==
2521             Line->First->OriginalColumn) {
2522       // Align comments for preprocessor lines with the # in column 0 if
2523       // preprocessor lines are not indented. Otherwise, align with the next
2524       // line.
2525       Line->Level =
2526           (Style.IndentPPDirectives != FormatStyle::PPDIS_BeforeHash &&
2527            (NextNonCommentLine->Type == LT_PreprocessorDirective ||
2528             NextNonCommentLine->Type == LT_ImportStatement))
2529               ? 0
2530               : NextNonCommentLine->Level;
2531     } else {
2532       NextNonCommentLine = Line->First->isNot(tok::r_brace) ? Line : nullptr;
2533     }
2534 
2535     setCommentLineLevels(Line->Children);
2536   }
2537 }
2538 
2539 static unsigned maxNestingDepth(const AnnotatedLine &Line) {
2540   unsigned Result = 0;
2541   for (const auto *Tok = Line.First; Tok != nullptr; Tok = Tok->Next)
2542     Result = std::max(Result, Tok->NestingLevel);
2543   return Result;
2544 }
2545 
2546 void TokenAnnotator::annotate(AnnotatedLine &Line) {
2547   for (auto &Child : Line.Children)
2548     annotate(*Child);
2549 
2550   AnnotatingParser Parser(Style, Line, Keywords);
2551   Line.Type = Parser.parseLine();
2552 
2553   // With very deep nesting, ExpressionParser uses lots of stack and the
2554   // formatting algorithm is very slow. We're not going to do a good job here
2555   // anyway - it's probably generated code being formatted by mistake.
2556   // Just skip the whole line.
2557   if (maxNestingDepth(Line) > 50)
2558     Line.Type = LT_Invalid;
2559 
2560   if (Line.Type == LT_Invalid)
2561     return;
2562 
2563   ExpressionParser ExprParser(Style, Keywords, Line);
2564   ExprParser.parse();
2565 
2566   if (Line.startsWith(TT_ObjCMethodSpecifier))
2567     Line.Type = LT_ObjCMethodDecl;
2568   else if (Line.startsWith(TT_ObjCDecl))
2569     Line.Type = LT_ObjCDecl;
2570   else if (Line.startsWith(TT_ObjCProperty))
2571     Line.Type = LT_ObjCProperty;
2572 
2573   Line.First->SpacesRequiredBefore = 1;
2574   Line.First->CanBreakBefore = Line.First->MustBreakBefore;
2575 }
2576 
2577 // This function heuristically determines whether 'Current' starts the name of a
2578 // function declaration.
2579 static bool isFunctionDeclarationName(bool IsCpp, const FormatToken &Current,
2580                                       const AnnotatedLine &Line) {
2581   auto skipOperatorName = [](const FormatToken *Next) -> const FormatToken * {
2582     for (; Next; Next = Next->Next) {
2583       if (Next->is(TT_OverloadedOperatorLParen))
2584         return Next;
2585       if (Next->is(TT_OverloadedOperator))
2586         continue;
2587       if (Next->isOneOf(tok::kw_new, tok::kw_delete)) {
2588         // For 'new[]' and 'delete[]'.
2589         if (Next->Next &&
2590             Next->Next->startsSequence(tok::l_square, tok::r_square))
2591           Next = Next->Next->Next;
2592         continue;
2593       }
2594       if (Next->startsSequence(tok::l_square, tok::r_square)) {
2595         // For operator[]().
2596         Next = Next->Next;
2597         continue;
2598       }
2599       if ((Next->isSimpleTypeSpecifier() || Next->is(tok::identifier)) &&
2600           Next->Next && Next->Next->isOneOf(tok::star, tok::amp, tok::ampamp)) {
2601         // For operator void*(), operator char*(), operator Foo*().
2602         Next = Next->Next;
2603         continue;
2604       }
2605       if (Next->is(TT_TemplateOpener) && Next->MatchingParen) {
2606         Next = Next->MatchingParen;
2607         continue;
2608       }
2609 
2610       break;
2611     }
2612     return nullptr;
2613   };
2614 
2615   // Find parentheses of parameter list.
2616   const FormatToken *Next = Current.Next;
2617   if (Current.is(tok::kw_operator)) {
2618     if (Current.Previous && Current.Previous->is(tok::coloncolon))
2619       return false;
2620     Next = skipOperatorName(Next);
2621   } else {
2622     if (!Current.is(TT_StartOfName) || Current.NestingLevel != 0)
2623       return false;
2624     for (; Next; Next = Next->Next) {
2625       if (Next->is(TT_TemplateOpener)) {
2626         Next = Next->MatchingParen;
2627       } else if (Next->is(tok::coloncolon)) {
2628         Next = Next->Next;
2629         if (!Next)
2630           return false;
2631         if (Next->is(tok::kw_operator)) {
2632           Next = skipOperatorName(Next->Next);
2633           break;
2634         }
2635         if (!Next->is(tok::identifier))
2636           return false;
2637       } else if (Next->is(tok::l_paren)) {
2638         break;
2639       } else {
2640         return false;
2641       }
2642     }
2643   }
2644 
2645   // Check whether parameter list can belong to a function declaration.
2646   if (!Next || !Next->is(tok::l_paren) || !Next->MatchingParen)
2647     return false;
2648   // If the lines ends with "{", this is likely a function definition.
2649   if (Line.Last->is(tok::l_brace))
2650     return true;
2651   if (Next->Next == Next->MatchingParen)
2652     return true; // Empty parentheses.
2653   // If there is an &/&& after the r_paren, this is likely a function.
2654   if (Next->MatchingParen->Next &&
2655       Next->MatchingParen->Next->is(TT_PointerOrReference))
2656     return true;
2657 
2658   // Check for K&R C function definitions (and C++ function definitions with
2659   // unnamed parameters), e.g.:
2660   //   int f(i)
2661   //   {
2662   //     return i + 1;
2663   //   }
2664   //   bool g(size_t = 0, bool b = false)
2665   //   {
2666   //     return !b;
2667   //   }
2668   if (IsCpp && Next->Next && Next->Next->is(tok::identifier) &&
2669       !Line.endsWith(tok::semi))
2670     return true;
2671 
2672   for (const FormatToken *Tok = Next->Next; Tok && Tok != Next->MatchingParen;
2673        Tok = Tok->Next) {
2674     if (Tok->is(TT_TypeDeclarationParen))
2675       return true;
2676     if (Tok->isOneOf(tok::l_paren, TT_TemplateOpener) && Tok->MatchingParen) {
2677       Tok = Tok->MatchingParen;
2678       continue;
2679     }
2680     if (Tok->is(tok::kw_const) || Tok->isSimpleTypeSpecifier() ||
2681         Tok->isOneOf(TT_PointerOrReference, TT_StartOfName, tok::ellipsis))
2682       return true;
2683     if (Tok->isOneOf(tok::l_brace, tok::string_literal, TT_ObjCMethodExpr) ||
2684         Tok->Tok.isLiteral())
2685       return false;
2686   }
2687   return false;
2688 }
2689 
2690 bool TokenAnnotator::mustBreakForReturnType(const AnnotatedLine &Line) const {
2691   assert(Line.MightBeFunctionDecl);
2692 
2693   if ((Style.AlwaysBreakAfterReturnType == FormatStyle::RTBS_TopLevel ||
2694        Style.AlwaysBreakAfterReturnType ==
2695            FormatStyle::RTBS_TopLevelDefinitions) &&
2696       Line.Level > 0)
2697     return false;
2698 
2699   switch (Style.AlwaysBreakAfterReturnType) {
2700   case FormatStyle::RTBS_None:
2701     return false;
2702   case FormatStyle::RTBS_All:
2703   case FormatStyle::RTBS_TopLevel:
2704     return true;
2705   case FormatStyle::RTBS_AllDefinitions:
2706   case FormatStyle::RTBS_TopLevelDefinitions:
2707     return Line.mightBeFunctionDefinition();
2708   }
2709 
2710   return false;
2711 }
2712 
2713 void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) {
2714   for (AnnotatedLine *ChildLine : Line.Children)
2715     calculateFormattingInformation(*ChildLine);
2716 
2717   Line.First->TotalLength =
2718       Line.First->IsMultiline ? Style.ColumnLimit
2719                               : Line.FirstStartColumn + Line.First->ColumnWidth;
2720   FormatToken *Current = Line.First->Next;
2721   bool InFunctionDecl = Line.MightBeFunctionDecl;
2722   bool AlignArrayOfStructures =
2723       (Style.AlignArrayOfStructures != FormatStyle::AIAS_None &&
2724        Line.Type == LT_ArrayOfStructInitializer);
2725   if (AlignArrayOfStructures)
2726     calculateArrayInitializerColumnList(Line);
2727 
2728   while (Current) {
2729     if (isFunctionDeclarationName(Style.isCpp(), *Current, Line))
2730       Current->setType(TT_FunctionDeclarationName);
2731     const FormatToken *Prev = Current->Previous;
2732     if (Current->is(TT_LineComment)) {
2733       if (Prev->is(BK_BracedInit) && Prev->opensScope())
2734         Current->SpacesRequiredBefore =
2735             (Style.Cpp11BracedListStyle && !Style.SpacesInParentheses) ? 0 : 1;
2736       else
2737         Current->SpacesRequiredBefore = Style.SpacesBeforeTrailingComments;
2738 
2739       // If we find a trailing comment, iterate backwards to determine whether
2740       // it seems to relate to a specific parameter. If so, break before that
2741       // parameter to avoid changing the comment's meaning. E.g. don't move 'b'
2742       // to the previous line in:
2743       //   SomeFunction(a,
2744       //                b, // comment
2745       //                c);
2746       if (!Current->HasUnescapedNewline) {
2747         for (FormatToken *Parameter = Current->Previous; Parameter;
2748              Parameter = Parameter->Previous) {
2749           if (Parameter->isOneOf(tok::comment, tok::r_brace))
2750             break;
2751           if (Parameter->Previous && Parameter->Previous->is(tok::comma)) {
2752             if (!Parameter->Previous->is(TT_CtorInitializerComma) &&
2753                 Parameter->HasUnescapedNewline)
2754               Parameter->MustBreakBefore = true;
2755             break;
2756           }
2757         }
2758       }
2759     } else if (Current->SpacesRequiredBefore == 0 &&
2760                spaceRequiredBefore(Line, *Current)) {
2761       Current->SpacesRequiredBefore = 1;
2762     }
2763 
2764     const auto &Children = Prev->Children;
2765     if (!Children.empty() && Children.back()->Last->is(TT_LineComment)) {
2766       Current->MustBreakBefore = true;
2767     } else {
2768       Current->MustBreakBefore =
2769           Current->MustBreakBefore || mustBreakBefore(Line, *Current);
2770       if (!Current->MustBreakBefore && InFunctionDecl &&
2771           Current->is(TT_FunctionDeclarationName))
2772         Current->MustBreakBefore = mustBreakForReturnType(Line);
2773     }
2774 
2775     Current->CanBreakBefore =
2776         Current->MustBreakBefore || canBreakBefore(Line, *Current);
2777     unsigned ChildSize = 0;
2778     if (Prev->Children.size() == 1) {
2779       FormatToken &LastOfChild = *Prev->Children[0]->Last;
2780       ChildSize = LastOfChild.isTrailingComment() ? Style.ColumnLimit
2781                                                   : LastOfChild.TotalLength + 1;
2782     }
2783     if (Current->MustBreakBefore || Prev->Children.size() > 1 ||
2784         (Prev->Children.size() == 1 &&
2785          Prev->Children[0]->First->MustBreakBefore) ||
2786         Current->IsMultiline)
2787       Current->TotalLength = Prev->TotalLength + Style.ColumnLimit;
2788     else
2789       Current->TotalLength = Prev->TotalLength + Current->ColumnWidth +
2790                              ChildSize + Current->SpacesRequiredBefore;
2791 
2792     if (Current->is(TT_CtorInitializerColon))
2793       InFunctionDecl = false;
2794 
2795     // FIXME: Only calculate this if CanBreakBefore is true once static
2796     // initializers etc. are sorted out.
2797     // FIXME: Move magic numbers to a better place.
2798 
2799     // Reduce penalty for aligning ObjC method arguments using the colon
2800     // alignment as this is the canonical way (still prefer fitting everything
2801     // into one line if possible). Trying to fit a whole expression into one
2802     // line should not force other line breaks (e.g. when ObjC method
2803     // expression is a part of other expression).
2804     Current->SplitPenalty = splitPenalty(Line, *Current, InFunctionDecl);
2805     if (Style.Language == FormatStyle::LK_ObjC &&
2806         Current->is(TT_SelectorName) && Current->ParameterIndex > 0) {
2807       if (Current->ParameterIndex == 1)
2808         Current->SplitPenalty += 5 * Current->BindingStrength;
2809     } else {
2810       Current->SplitPenalty += 20 * Current->BindingStrength;
2811     }
2812 
2813     Current = Current->Next;
2814   }
2815 
2816   calculateUnbreakableTailLengths(Line);
2817   unsigned IndentLevel = Line.Level;
2818   for (Current = Line.First; Current != nullptr; Current = Current->Next) {
2819     if (Current->Role)
2820       Current->Role->precomputeFormattingInfos(Current);
2821     if (Current->MatchingParen &&
2822         Current->MatchingParen->opensBlockOrBlockTypeList(Style) &&
2823         IndentLevel > 0)
2824       --IndentLevel;
2825     Current->IndentLevel = IndentLevel;
2826     if (Current->opensBlockOrBlockTypeList(Style))
2827       ++IndentLevel;
2828   }
2829 
2830   LLVM_DEBUG({ printDebugInfo(Line); });
2831 }
2832 
2833 void TokenAnnotator::calculateUnbreakableTailLengths(AnnotatedLine &Line) {
2834   unsigned UnbreakableTailLength = 0;
2835   FormatToken *Current = Line.Last;
2836   while (Current) {
2837     Current->UnbreakableTailLength = UnbreakableTailLength;
2838     if (Current->CanBreakBefore ||
2839         Current->isOneOf(tok::comment, tok::string_literal)) {
2840       UnbreakableTailLength = 0;
2841     } else {
2842       UnbreakableTailLength +=
2843           Current->ColumnWidth + Current->SpacesRequiredBefore;
2844     }
2845     Current = Current->Previous;
2846   }
2847 }
2848 
2849 void TokenAnnotator::calculateArrayInitializerColumnList(AnnotatedLine &Line) {
2850   if (Line.First == Line.Last)
2851     return;
2852   auto *CurrentToken = Line.First;
2853   CurrentToken->ArrayInitializerLineStart = true;
2854   unsigned Depth = 0;
2855   while (CurrentToken != nullptr && CurrentToken != Line.Last) {
2856     if (CurrentToken->is(tok::l_brace)) {
2857       CurrentToken->IsArrayInitializer = true;
2858       if (CurrentToken->Next != nullptr)
2859         CurrentToken->Next->MustBreakBefore = true;
2860       CurrentToken =
2861           calculateInitializerColumnList(Line, CurrentToken->Next, Depth + 1);
2862     } else {
2863       CurrentToken = CurrentToken->Next;
2864     }
2865   }
2866 }
2867 
2868 FormatToken *TokenAnnotator::calculateInitializerColumnList(
2869     AnnotatedLine &Line, FormatToken *CurrentToken, unsigned Depth) {
2870   while (CurrentToken != nullptr && CurrentToken != Line.Last) {
2871     if (CurrentToken->is(tok::l_brace))
2872       ++Depth;
2873     else if (CurrentToken->is(tok::r_brace))
2874       --Depth;
2875     if (Depth == 2 && CurrentToken->isOneOf(tok::l_brace, tok::comma)) {
2876       CurrentToken = CurrentToken->Next;
2877       if (CurrentToken == nullptr)
2878         break;
2879       CurrentToken->StartsColumn = true;
2880       CurrentToken = CurrentToken->Previous;
2881     }
2882     CurrentToken = CurrentToken->Next;
2883   }
2884   return CurrentToken;
2885 }
2886 
2887 unsigned TokenAnnotator::splitPenalty(const AnnotatedLine &Line,
2888                                       const FormatToken &Tok,
2889                                       bool InFunctionDecl) {
2890   const FormatToken &Left = *Tok.Previous;
2891   const FormatToken &Right = Tok;
2892 
2893   if (Left.is(tok::semi))
2894     return 0;
2895 
2896   if (Style.Language == FormatStyle::LK_Java) {
2897     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_throws))
2898       return 1;
2899     if (Right.is(Keywords.kw_implements))
2900       return 2;
2901     if (Left.is(tok::comma) && Left.NestingLevel == 0)
2902       return 3;
2903   } else if (Style.isJavaScript()) {
2904     if (Right.is(Keywords.kw_function) && Left.isNot(tok::comma))
2905       return 100;
2906     if (Left.is(TT_JsTypeColon))
2907       return 35;
2908     if ((Left.is(TT_TemplateString) && Left.TokenText.endswith("${")) ||
2909         (Right.is(TT_TemplateString) && Right.TokenText.startswith("}")))
2910       return 100;
2911     // Prefer breaking call chains (".foo") over empty "{}", "[]" or "()".
2912     if (Left.opensScope() && Right.closesScope())
2913       return 200;
2914   }
2915 
2916   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
2917     return 1;
2918   if (Right.is(tok::l_square)) {
2919     if (Style.Language == FormatStyle::LK_Proto)
2920       return 1;
2921     if (Left.is(tok::r_square))
2922       return 200;
2923     // Slightly prefer formatting local lambda definitions like functions.
2924     if (Right.is(TT_LambdaLSquare) && Left.is(tok::equal))
2925       return 35;
2926     if (!Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
2927                        TT_ArrayInitializerLSquare,
2928                        TT_DesignatedInitializerLSquare, TT_AttributeSquare))
2929       return 500;
2930   }
2931 
2932   if (Left.is(tok::coloncolon) ||
2933       (Right.is(tok::period) && Style.Language == FormatStyle::LK_Proto))
2934     return 500;
2935   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
2936       Right.is(tok::kw_operator)) {
2937     if (Line.startsWith(tok::kw_for) && Right.PartOfMultiVariableDeclStmt)
2938       return 3;
2939     if (Left.is(TT_StartOfName))
2940       return 110;
2941     if (InFunctionDecl && Right.NestingLevel == 0)
2942       return Style.PenaltyReturnTypeOnItsOwnLine;
2943     return 200;
2944   }
2945   if (Right.is(TT_PointerOrReference))
2946     return 190;
2947   if (Right.is(TT_LambdaArrow))
2948     return 110;
2949   if (Left.is(tok::equal) && Right.is(tok::l_brace))
2950     return 160;
2951   if (Left.is(TT_CastRParen))
2952     return 100;
2953   if (Left.isOneOf(tok::kw_class, tok::kw_struct))
2954     return 5000;
2955   if (Left.is(tok::comment))
2956     return 1000;
2957 
2958   if (Left.isOneOf(TT_RangeBasedForLoopColon, TT_InheritanceColon,
2959                    TT_CtorInitializerColon))
2960     return 2;
2961 
2962   if (Right.isMemberAccess()) {
2963     // Breaking before the "./->" of a chained call/member access is reasonably
2964     // cheap, as formatting those with one call per line is generally
2965     // desirable. In particular, it should be cheaper to break before the call
2966     // than it is to break inside a call's parameters, which could lead to weird
2967     // "hanging" indents. The exception is the very last "./->" to support this
2968     // frequent pattern:
2969     //
2970     //   aaaaaaaa.aaaaaaaa.bbbbbbb().ccccccccccccccccccccc(
2971     //       dddddddd);
2972     //
2973     // which might otherwise be blown up onto many lines. Here, clang-format
2974     // won't produce "hanging" indents anyway as there is no other trailing
2975     // call.
2976     //
2977     // Also apply higher penalty is not a call as that might lead to a wrapping
2978     // like:
2979     //
2980     //   aaaaaaa
2981     //       .aaaaaaaaa.bbbbbbbb(cccccccc);
2982     return !Right.NextOperator || !Right.NextOperator->Previous->closesScope()
2983                ? 150
2984                : 35;
2985   }
2986 
2987   if (Right.is(TT_TrailingAnnotation) &&
2988       (!Right.Next || Right.Next->isNot(tok::l_paren))) {
2989     // Moving trailing annotations to the next line is fine for ObjC method
2990     // declarations.
2991     if (Line.startsWith(TT_ObjCMethodSpecifier))
2992       return 10;
2993     // Generally, breaking before a trailing annotation is bad unless it is
2994     // function-like. It seems to be especially preferable to keep standard
2995     // annotations (i.e. "const", "final" and "override") on the same line.
2996     // Use a slightly higher penalty after ")" so that annotations like
2997     // "const override" are kept together.
2998     bool is_short_annotation = Right.TokenText.size() < 10;
2999     return (Left.is(tok::r_paren) ? 100 : 120) + (is_short_annotation ? 50 : 0);
3000   }
3001 
3002   // In for-loops, prefer breaking at ',' and ';'.
3003   if (Line.startsWith(tok::kw_for) && Left.is(tok::equal))
3004     return 4;
3005 
3006   // In Objective-C method expressions, prefer breaking before "param:" over
3007   // breaking after it.
3008   if (Right.is(TT_SelectorName))
3009     return 0;
3010   if (Left.is(tok::colon) && Left.is(TT_ObjCMethodExpr))
3011     return Line.MightBeFunctionDecl ? 50 : 500;
3012 
3013   // In Objective-C type declarations, avoid breaking after the category's
3014   // open paren (we'll prefer breaking after the protocol list's opening
3015   // angle bracket, if present).
3016   if (Line.Type == LT_ObjCDecl && Left.is(tok::l_paren) && Left.Previous &&
3017       Left.Previous->isOneOf(tok::identifier, tok::greater))
3018     return 500;
3019 
3020   if (Left.is(tok::l_paren) && Style.PenaltyBreakOpenParenthesis != 0)
3021     return Style.PenaltyBreakOpenParenthesis;
3022   if (Left.is(tok::l_paren) && InFunctionDecl &&
3023       Style.AlignAfterOpenBracket != FormatStyle::BAS_DontAlign)
3024     return 100;
3025   if (Left.is(tok::l_paren) && Left.Previous &&
3026       (Left.Previous->is(tok::kw_for) || Left.Previous->isIf()))
3027     return 1000;
3028   if (Left.is(tok::equal) && InFunctionDecl)
3029     return 110;
3030   if (Right.is(tok::r_brace))
3031     return 1;
3032   if (Left.is(TT_TemplateOpener))
3033     return 100;
3034   if (Left.opensScope()) {
3035     // If we aren't aligning after opening parens/braces we can always break
3036     // here unless the style does not want us to place all arguments on the
3037     // next line.
3038     if (Style.AlignAfterOpenBracket == FormatStyle::BAS_DontAlign &&
3039         (Left.ParameterCount <= 1 || Style.AllowAllArgumentsOnNextLine))
3040       return 0;
3041     if (Left.is(tok::l_brace) && !Style.Cpp11BracedListStyle)
3042       return 19;
3043     return Left.ParameterCount > 1 ? Style.PenaltyBreakBeforeFirstCallParameter
3044                                    : 19;
3045   }
3046   if (Left.is(TT_JavaAnnotation))
3047     return 50;
3048 
3049   if (Left.is(TT_UnaryOperator))
3050     return 60;
3051   if (Left.isOneOf(tok::plus, tok::comma) && Left.Previous &&
3052       Left.Previous->isLabelString() &&
3053       (Left.NextOperator || Left.OperatorIndex != 0))
3054     return 50;
3055   if (Right.is(tok::plus) && Left.isLabelString() &&
3056       (Right.NextOperator || Right.OperatorIndex != 0))
3057     return 25;
3058   if (Left.is(tok::comma))
3059     return 1;
3060   if (Right.is(tok::lessless) && Left.isLabelString() &&
3061       (Right.NextOperator || Right.OperatorIndex != 1))
3062     return 25;
3063   if (Right.is(tok::lessless)) {
3064     // Breaking at a << is really cheap.
3065     if (!Left.is(tok::r_paren) || Right.OperatorIndex > 0)
3066       // Slightly prefer to break before the first one in log-like statements.
3067       return 2;
3068     return 1;
3069   }
3070   if (Left.ClosesTemplateDeclaration)
3071     return Style.PenaltyBreakTemplateDeclaration;
3072   if (Left.ClosesRequiresClause)
3073     return 0;
3074   if (Left.is(TT_ConditionalExpr))
3075     return prec::Conditional;
3076   prec::Level Level = Left.getPrecedence();
3077   if (Level == prec::Unknown)
3078     Level = Right.getPrecedence();
3079   if (Level == prec::Assignment)
3080     return Style.PenaltyBreakAssignment;
3081   if (Level != prec::Unknown)
3082     return Level;
3083 
3084   return 3;
3085 }
3086 
3087 bool TokenAnnotator::spaceRequiredBeforeParens(const FormatToken &Right) const {
3088   if (Style.SpaceBeforeParens == FormatStyle::SBPO_Always)
3089     return true;
3090   if (Right.is(TT_OverloadedOperatorLParen) &&
3091       Style.SpaceBeforeParensOptions.AfterOverloadedOperator)
3092     return true;
3093   if (Style.SpaceBeforeParensOptions.BeforeNonEmptyParentheses &&
3094       Right.ParameterCount > 0)
3095     return true;
3096   return false;
3097 }
3098 
3099 bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
3100                                           const FormatToken &Left,
3101                                           const FormatToken &Right) {
3102   if (Left.is(tok::kw_return) &&
3103       !Right.isOneOf(tok::semi, tok::r_paren, tok::hashhash))
3104     return true;
3105   if (Style.isJson() && Left.is(tok::string_literal) && Right.is(tok::colon))
3106     return false;
3107   if (Left.is(Keywords.kw_assert) && Style.Language == FormatStyle::LK_Java)
3108     return true;
3109   if (Style.ObjCSpaceAfterProperty && Line.Type == LT_ObjCProperty &&
3110       Left.Tok.getObjCKeywordID() == tok::objc_property)
3111     return true;
3112   if (Right.is(tok::hashhash))
3113     return Left.is(tok::hash);
3114   if (Left.isOneOf(tok::hashhash, tok::hash))
3115     return Right.is(tok::hash);
3116   if ((Left.is(tok::l_paren) && Right.is(tok::r_paren)) ||
3117       (Left.is(tok::l_brace) && Left.isNot(BK_Block) &&
3118        Right.is(tok::r_brace) && Right.isNot(BK_Block)))
3119     return Style.SpaceInEmptyParentheses;
3120   if (Style.SpacesInConditionalStatement) {
3121     const FormatToken *LeftParen = nullptr;
3122     if (Left.is(tok::l_paren))
3123       LeftParen = &Left;
3124     else if (Right.is(tok::r_paren) && Right.MatchingParen)
3125       LeftParen = Right.MatchingParen;
3126     if (LeftParen && LeftParen->Previous &&
3127         isKeywordWithCondition(*LeftParen->Previous))
3128       return true;
3129   }
3130 
3131   // auto{x} auto(x)
3132   if (Left.is(tok::kw_auto) && Right.isOneOf(tok::l_paren, tok::l_brace))
3133     return false;
3134 
3135   // operator co_await(x)
3136   if (Right.is(tok::l_paren) && Left.is(tok::kw_co_await) && Left.Previous &&
3137       Left.Previous->is(tok::kw_operator))
3138     return false;
3139   // co_await (x), co_yield (x), co_return (x)
3140   if (Left.isOneOf(tok::kw_co_await, tok::kw_co_yield, tok::kw_co_return) &&
3141       !Right.isOneOf(tok::semi, tok::r_paren))
3142     return true;
3143 
3144   if (Left.is(tok::l_paren) || Right.is(tok::r_paren))
3145     return (Right.is(TT_CastRParen) ||
3146             (Left.MatchingParen && Left.MatchingParen->is(TT_CastRParen)))
3147                ? Style.SpacesInCStyleCastParentheses
3148                : Style.SpacesInParentheses;
3149   if (Right.isOneOf(tok::semi, tok::comma))
3150     return false;
3151   if (Right.is(tok::less) && Line.Type == LT_ObjCDecl) {
3152     bool IsLightweightGeneric = Right.MatchingParen &&
3153                                 Right.MatchingParen->Next &&
3154                                 Right.MatchingParen->Next->is(tok::colon);
3155     return !IsLightweightGeneric && Style.ObjCSpaceBeforeProtocolList;
3156   }
3157   if (Right.is(tok::less) && Left.is(tok::kw_template))
3158     return Style.SpaceAfterTemplateKeyword;
3159   if (Left.isOneOf(tok::exclaim, tok::tilde))
3160     return false;
3161   if (Left.is(tok::at) &&
3162       Right.isOneOf(tok::identifier, tok::string_literal, tok::char_constant,
3163                     tok::numeric_constant, tok::l_paren, tok::l_brace,
3164                     tok::kw_true, tok::kw_false))
3165     return false;
3166   if (Left.is(tok::colon))
3167     return !Left.is(TT_ObjCMethodExpr);
3168   if (Left.is(tok::coloncolon))
3169     return false;
3170   if (Left.is(tok::less) || Right.isOneOf(tok::greater, tok::less)) {
3171     if (Style.Language == FormatStyle::LK_TextProto ||
3172         (Style.Language == FormatStyle::LK_Proto &&
3173          (Left.is(TT_DictLiteral) || Right.is(TT_DictLiteral)))) {
3174       // Format empty list as `<>`.
3175       if (Left.is(tok::less) && Right.is(tok::greater))
3176         return false;
3177       return !Style.Cpp11BracedListStyle;
3178     }
3179     return false;
3180   }
3181   if (Right.is(tok::ellipsis))
3182     return Left.Tok.isLiteral() || (Left.is(tok::identifier) && Left.Previous &&
3183                                     Left.Previous->is(tok::kw_case));
3184   if (Left.is(tok::l_square) && Right.is(tok::amp))
3185     return Style.SpacesInSquareBrackets;
3186   if (Right.is(TT_PointerOrReference)) {
3187     if (Left.is(tok::r_paren) && Line.MightBeFunctionDecl) {
3188       if (!Left.MatchingParen)
3189         return true;
3190       FormatToken *TokenBeforeMatchingParen =
3191           Left.MatchingParen->getPreviousNonComment();
3192       if (!TokenBeforeMatchingParen || !Left.is(TT_TypeDeclarationParen))
3193         return true;
3194     }
3195     // Add a space if the previous token is a pointer qualifier or the closing
3196     // parenthesis of __attribute__(()) expression and the style requires spaces
3197     // after pointer qualifiers.
3198     if ((Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_After ||
3199          Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Both) &&
3200         (Left.is(TT_AttributeParen) || Left.canBePointerOrReferenceQualifier()))
3201       return true;
3202     if (Left.Tok.isLiteral())
3203       return true;
3204     // for (auto a = 0, b = 0; const auto & c : {1, 2, 3})
3205     if (Left.isTypeOrIdentifier() && Right.Next && Right.Next->Next &&
3206         Right.Next->Next->is(TT_RangeBasedForLoopColon))
3207       return getTokenPointerOrReferenceAlignment(Right) !=
3208              FormatStyle::PAS_Left;
3209     return !Left.isOneOf(TT_PointerOrReference, tok::l_paren) &&
3210            (getTokenPointerOrReferenceAlignment(Right) !=
3211                 FormatStyle::PAS_Left ||
3212             (Line.IsMultiVariableDeclStmt &&
3213              (Left.NestingLevel == 0 ||
3214               (Left.NestingLevel == 1 && startsWithInitStatement(Line)))));
3215   }
3216   if (Right.is(TT_FunctionTypeLParen) && Left.isNot(tok::l_paren) &&
3217       (!Left.is(TT_PointerOrReference) ||
3218        (getTokenPointerOrReferenceAlignment(Left) != FormatStyle::PAS_Right &&
3219         !Line.IsMultiVariableDeclStmt)))
3220     return true;
3221   if (Left.is(TT_PointerOrReference)) {
3222     // Add a space if the next token is a pointer qualifier and the style
3223     // requires spaces before pointer qualifiers.
3224     if ((Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Before ||
3225          Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Both) &&
3226         Right.canBePointerOrReferenceQualifier())
3227       return true;
3228     // & 1
3229     if (Right.Tok.isLiteral())
3230       return true;
3231     // & /* comment
3232     if (Right.is(TT_BlockComment))
3233       return true;
3234     // foo() -> const Bar * override/final
3235     if (Right.isOneOf(Keywords.kw_override, Keywords.kw_final) &&
3236         !Right.is(TT_StartOfName))
3237       return true;
3238     // & {
3239     if (Right.is(tok::l_brace) && Right.is(BK_Block))
3240       return true;
3241     // for (auto a = 0, b = 0; const auto& c : {1, 2, 3})
3242     if (Left.Previous && Left.Previous->isTypeOrIdentifier() && Right.Next &&
3243         Right.Next->is(TT_RangeBasedForLoopColon))
3244       return getTokenPointerOrReferenceAlignment(Left) !=
3245              FormatStyle::PAS_Right;
3246     if (Right.isOneOf(TT_PointerOrReference, TT_ArraySubscriptLSquare,
3247                       tok::l_paren))
3248       return false;
3249     if (getTokenPointerOrReferenceAlignment(Left) == FormatStyle::PAS_Right)
3250       return false;
3251     // FIXME: Setting IsMultiVariableDeclStmt for the whole line is error-prone,
3252     // because it does not take into account nested scopes like lambdas.
3253     // In multi-variable declaration statements, attach */& to the variable
3254     // independently of the style. However, avoid doing it if we are in a nested
3255     // scope, e.g. lambda. We still need to special-case statements with
3256     // initializers.
3257     if (Line.IsMultiVariableDeclStmt &&
3258         (Left.NestingLevel == Line.First->NestingLevel ||
3259          ((Left.NestingLevel == Line.First->NestingLevel + 1) &&
3260           startsWithInitStatement(Line))))
3261       return false;
3262     return Left.Previous && !Left.Previous->isOneOf(
3263                                 tok::l_paren, tok::coloncolon, tok::l_square);
3264   }
3265   // Ensure right pointer alignment with ellipsis e.g. int *...P
3266   if (Left.is(tok::ellipsis) && Left.Previous &&
3267       Left.Previous->isOneOf(tok::star, tok::amp, tok::ampamp))
3268     return Style.PointerAlignment != FormatStyle::PAS_Right;
3269 
3270   if (Right.is(tok::star) && Left.is(tok::l_paren))
3271     return false;
3272   if (Left.is(tok::star) && Right.isOneOf(tok::star, tok::amp, tok::ampamp))
3273     return false;
3274   if (Right.isOneOf(tok::star, tok::amp, tok::ampamp)) {
3275     const FormatToken *Previous = &Left;
3276     while (Previous && !Previous->is(tok::kw_operator)) {
3277       if (Previous->is(tok::identifier) || Previous->isSimpleTypeSpecifier()) {
3278         Previous = Previous->getPreviousNonComment();
3279         continue;
3280       }
3281       if (Previous->is(TT_TemplateCloser) && Previous->MatchingParen) {
3282         Previous = Previous->MatchingParen->getPreviousNonComment();
3283         continue;
3284       }
3285       if (Previous->is(tok::coloncolon)) {
3286         Previous = Previous->getPreviousNonComment();
3287         continue;
3288       }
3289       break;
3290     }
3291     // Space between the type and the * in:
3292     //   operator void*()
3293     //   operator char*()
3294     //   operator void const*()
3295     //   operator void volatile*()
3296     //   operator /*comment*/ const char*()
3297     //   operator volatile /*comment*/ char*()
3298     //   operator Foo*()
3299     //   operator C<T>*()
3300     //   operator std::Foo*()
3301     //   operator C<T>::D<U>*()
3302     // dependent on PointerAlignment style.
3303     if (Previous) {
3304       if (Previous->endsSequence(tok::kw_operator))
3305         return Style.PointerAlignment != FormatStyle::PAS_Left;
3306       if (Previous->is(tok::kw_const) || Previous->is(tok::kw_volatile))
3307         return (Style.PointerAlignment != FormatStyle::PAS_Left) ||
3308                (Style.SpaceAroundPointerQualifiers ==
3309                 FormatStyle::SAPQ_After) ||
3310                (Style.SpaceAroundPointerQualifiers == FormatStyle::SAPQ_Both);
3311     }
3312   }
3313   const auto SpaceRequiredForArrayInitializerLSquare =
3314       [](const FormatToken &LSquareTok, const FormatStyle &Style) {
3315         return Style.SpacesInContainerLiterals ||
3316                ((Style.Language == FormatStyle::LK_Proto ||
3317                  Style.Language == FormatStyle::LK_TextProto) &&
3318                 !Style.Cpp11BracedListStyle &&
3319                 LSquareTok.endsSequence(tok::l_square, tok::colon,
3320                                         TT_SelectorName));
3321       };
3322   if (Left.is(tok::l_square))
3323     return (Left.is(TT_ArrayInitializerLSquare) && Right.isNot(tok::r_square) &&
3324             SpaceRequiredForArrayInitializerLSquare(Left, Style)) ||
3325            (Left.isOneOf(TT_ArraySubscriptLSquare, TT_StructuredBindingLSquare,
3326                          TT_LambdaLSquare) &&
3327             Style.SpacesInSquareBrackets && Right.isNot(tok::r_square));
3328   if (Right.is(tok::r_square))
3329     return Right.MatchingParen &&
3330            ((Right.MatchingParen->is(TT_ArrayInitializerLSquare) &&
3331              SpaceRequiredForArrayInitializerLSquare(*Right.MatchingParen,
3332                                                      Style)) ||
3333             (Style.SpacesInSquareBrackets &&
3334              Right.MatchingParen->isOneOf(TT_ArraySubscriptLSquare,
3335                                           TT_StructuredBindingLSquare,
3336                                           TT_LambdaLSquare)) ||
3337             Right.MatchingParen->is(TT_AttributeParen));
3338   if (Right.is(tok::l_square) &&
3339       !Right.isOneOf(TT_ObjCMethodExpr, TT_LambdaLSquare,
3340                      TT_DesignatedInitializerLSquare,
3341                      TT_StructuredBindingLSquare, TT_AttributeSquare) &&
3342       !Left.isOneOf(tok::numeric_constant, TT_DictLiteral) &&
3343       !(!Left.is(tok::r_square) && Style.SpaceBeforeSquareBrackets &&
3344         Right.is(TT_ArraySubscriptLSquare)))
3345     return false;
3346   if (Left.is(tok::l_brace) && Right.is(tok::r_brace))
3347     return !Left.Children.empty(); // No spaces in "{}".
3348   if ((Left.is(tok::l_brace) && Left.isNot(BK_Block)) ||
3349       (Right.is(tok::r_brace) && Right.MatchingParen &&
3350        Right.MatchingParen->isNot(BK_Block)))
3351     return Style.Cpp11BracedListStyle ? Style.SpacesInParentheses : true;
3352   if (Left.is(TT_BlockComment))
3353     // No whitespace in x(/*foo=*/1), except for JavaScript.
3354     return Style.isJavaScript() || !Left.TokenText.endswith("=*/");
3355 
3356   // Space between template and attribute.
3357   // e.g. template <typename T> [[nodiscard]] ...
3358   if (Left.is(TT_TemplateCloser) && Right.is(TT_AttributeSquare))
3359     return true;
3360   // Space before parentheses common for all languages
3361   if (Right.is(tok::l_paren)) {
3362     if (Left.is(TT_TemplateCloser) && Right.isNot(TT_FunctionTypeLParen))
3363       return spaceRequiredBeforeParens(Right);
3364     if (Left.isOneOf(TT_RequiresClause, TT_RequiresClauseInARequiresExpression))
3365       return Style.SpaceBeforeParensOptions.AfterRequiresInClause ||
3366              spaceRequiredBeforeParens(Right);
3367     if (Left.is(TT_RequiresExpression))
3368       return Style.SpaceBeforeParensOptions.AfterRequiresInExpression ||
3369              spaceRequiredBeforeParens(Right);
3370     if ((Left.is(tok::r_paren) && Left.is(TT_AttributeParen)) ||
3371         (Left.is(tok::r_square) && Left.is(TT_AttributeSquare)))
3372       return true;
3373     if (Left.is(TT_ForEachMacro))
3374       return Style.SpaceBeforeParensOptions.AfterForeachMacros ||
3375              spaceRequiredBeforeParens(Right);
3376     if (Left.is(TT_IfMacro))
3377       return Style.SpaceBeforeParensOptions.AfterIfMacros ||
3378              spaceRequiredBeforeParens(Right);
3379     if (Line.Type == LT_ObjCDecl)
3380       return true;
3381     if (Left.is(tok::semi))
3382       return true;
3383     if (Left.isOneOf(tok::pp_elif, tok::kw_for, tok::kw_while, tok::kw_switch,
3384                      tok::kw_case, TT_ForEachMacro, TT_ObjCForIn) ||
3385         Left.isIf(Line.Type != LT_PreprocessorDirective))
3386       return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3387              spaceRequiredBeforeParens(Right);
3388 
3389     // TODO add Operator overloading specific Options to
3390     // SpaceBeforeParensOptions
3391     if (Right.is(TT_OverloadedOperatorLParen))
3392       return spaceRequiredBeforeParens(Right);
3393     // Function declaration or definition
3394     if (Line.MightBeFunctionDecl && (Left.is(TT_FunctionDeclarationName))) {
3395       if (Line.mightBeFunctionDefinition())
3396         return Style.SpaceBeforeParensOptions.AfterFunctionDefinitionName ||
3397                spaceRequiredBeforeParens(Right);
3398       else
3399         return Style.SpaceBeforeParensOptions.AfterFunctionDeclarationName ||
3400                spaceRequiredBeforeParens(Right);
3401     }
3402     // Lambda
3403     if (Line.Type != LT_PreprocessorDirective && Left.is(tok::r_square) &&
3404         Left.MatchingParen && Left.MatchingParen->is(TT_LambdaLSquare))
3405       return Style.SpaceBeforeParensOptions.AfterFunctionDefinitionName ||
3406              spaceRequiredBeforeParens(Right);
3407     if (!Left.Previous || Left.Previous->isNot(tok::period)) {
3408       if (Left.isOneOf(tok::kw_try, Keywords.kw___except, tok::kw_catch))
3409         return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3410                spaceRequiredBeforeParens(Right);
3411       if (Left.isOneOf(tok::kw_new, tok::kw_delete))
3412         return ((!Line.MightBeFunctionDecl || !Left.Previous) &&
3413                 Style.SpaceBeforeParens != FormatStyle::SBPO_Never) ||
3414                spaceRequiredBeforeParens(Right);
3415 
3416       if (Left.is(tok::r_square) && Left.MatchingParen &&
3417           Left.MatchingParen->Previous &&
3418           Left.MatchingParen->Previous->is(tok::kw_delete))
3419         return (Style.SpaceBeforeParens != FormatStyle::SBPO_Never) ||
3420                spaceRequiredBeforeParens(Right);
3421     }
3422     if (Line.Type != LT_PreprocessorDirective &&
3423         (Left.is(tok::identifier) || Left.isFunctionLikeKeyword() ||
3424          Left.is(tok::r_paren) || Left.isSimpleTypeSpecifier()))
3425       return spaceRequiredBeforeParens(Right);
3426     return false;
3427   }
3428   if (Left.is(tok::at) && Right.Tok.getObjCKeywordID() != tok::objc_not_keyword)
3429     return false;
3430   if (Right.is(TT_UnaryOperator))
3431     return !Left.isOneOf(tok::l_paren, tok::l_square, tok::at) &&
3432            (Left.isNot(tok::colon) || Left.isNot(TT_ObjCMethodExpr));
3433   if ((Left.isOneOf(tok::identifier, tok::greater, tok::r_square,
3434                     tok::r_paren) ||
3435        Left.isSimpleTypeSpecifier()) &&
3436       Right.is(tok::l_brace) && Right.getNextNonComment() &&
3437       Right.isNot(BK_Block))
3438     return false;
3439   if (Left.is(tok::period) || Right.is(tok::period))
3440     return false;
3441   // u#str, U#str, L#str, u8#str
3442   // uR#str, UR#str, LR#str, u8R#str
3443   if (Right.is(tok::hash) && Left.is(tok::identifier) &&
3444       (Left.TokenText == "L" || Left.TokenText == "u" ||
3445        Left.TokenText == "U" || Left.TokenText == "u8" ||
3446        Left.TokenText == "LR" || Left.TokenText == "uR" ||
3447        Left.TokenText == "UR" || Left.TokenText == "u8R"))
3448     return false;
3449   if (Left.is(TT_TemplateCloser) && Left.MatchingParen &&
3450       Left.MatchingParen->Previous &&
3451       (Left.MatchingParen->Previous->is(tok::period) ||
3452        Left.MatchingParen->Previous->is(tok::coloncolon)))
3453     // Java call to generic function with explicit type:
3454     // A.<B<C<...>>>DoSomething();
3455     // A::<B<C<...>>>DoSomething();  // With a Java 8 method reference.
3456     return false;
3457   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_square))
3458     return false;
3459   if (Left.is(tok::l_brace) && Left.endsSequence(TT_DictLiteral, tok::at))
3460     // Objective-C dictionary literal -> no space after opening brace.
3461     return false;
3462   if (Right.is(tok::r_brace) && Right.MatchingParen &&
3463       Right.MatchingParen->endsSequence(TT_DictLiteral, tok::at))
3464     // Objective-C dictionary literal -> no space before closing brace.
3465     return false;
3466   if (Right.getType() == TT_TrailingAnnotation &&
3467       Right.isOneOf(tok::amp, tok::ampamp) &&
3468       Left.isOneOf(tok::kw_const, tok::kw_volatile) &&
3469       (!Right.Next || Right.Next->is(tok::semi)))
3470     // Match const and volatile ref-qualifiers without any additional
3471     // qualifiers such as
3472     // void Fn() const &;
3473     return getTokenReferenceAlignment(Right) != FormatStyle::PAS_Left;
3474 
3475   return true;
3476 }
3477 
3478 bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
3479                                          const FormatToken &Right) {
3480   const FormatToken &Left = *Right.Previous;
3481 
3482   // If the token is finalized don't touch it (as it could be in a
3483   // clang-format-off section).
3484   if (Left.Finalized)
3485     return Right.hasWhitespaceBefore();
3486 
3487   if (Right.Tok.getIdentifierInfo() && Left.Tok.getIdentifierInfo())
3488     return true; // Never ever merge two identifiers.
3489 
3490   // Leave a space between * and /* to avoid C4138 `comment end` found outside
3491   // of comment.
3492   if (Left.is(tok::star) && Right.is(tok::comment))
3493     return true;
3494 
3495   if (Style.isCpp()) {
3496     // Space between import <iostream>.
3497     // or import .....;
3498     if (Left.is(Keywords.kw_import) && Right.isOneOf(tok::less, tok::ellipsis))
3499       return true;
3500     // Space between `module :` and `import :`.
3501     if (Left.isOneOf(Keywords.kw_module, Keywords.kw_import) &&
3502         Right.is(TT_ModulePartitionColon))
3503       return true;
3504     // No space between import foo:bar but keep a space between import :bar;
3505     if (Left.is(tok::identifier) && Right.is(TT_ModulePartitionColon))
3506       return false;
3507     // No space between :bar;
3508     if (Left.is(TT_ModulePartitionColon) &&
3509         Right.isOneOf(tok::identifier, tok::kw_private))
3510       return false;
3511     if (Left.is(tok::ellipsis) && Right.is(tok::identifier) &&
3512         Line.First->is(Keywords.kw_import))
3513       return false;
3514     // Space in __attribute__((attr)) ::type.
3515     if (Left.is(TT_AttributeParen) && Right.is(tok::coloncolon))
3516       return true;
3517 
3518     if (Left.is(tok::kw_operator))
3519       return Right.is(tok::coloncolon);
3520     if (Right.is(tok::l_brace) && Right.is(BK_BracedInit) &&
3521         !Left.opensScope() && Style.SpaceBeforeCpp11BracedList)
3522       return true;
3523     if (Left.is(tok::less) && Left.is(TT_OverloadedOperator) &&
3524         Right.is(TT_TemplateOpener))
3525       return true;
3526   } else if (Style.Language == FormatStyle::LK_Proto ||
3527              Style.Language == FormatStyle::LK_TextProto) {
3528     if (Right.is(tok::period) &&
3529         Left.isOneOf(Keywords.kw_optional, Keywords.kw_required,
3530                      Keywords.kw_repeated, Keywords.kw_extend))
3531       return true;
3532     if (Right.is(tok::l_paren) &&
3533         Left.isOneOf(Keywords.kw_returns, Keywords.kw_option))
3534       return true;
3535     if (Right.isOneOf(tok::l_brace, tok::less) && Left.is(TT_SelectorName))
3536       return true;
3537     // Slashes occur in text protocol extension syntax: [type/type] { ... }.
3538     if (Left.is(tok::slash) || Right.is(tok::slash))
3539       return false;
3540     if (Left.MatchingParen &&
3541         Left.MatchingParen->is(TT_ProtoExtensionLSquare) &&
3542         Right.isOneOf(tok::l_brace, tok::less))
3543       return !Style.Cpp11BracedListStyle;
3544     // A percent is probably part of a formatting specification, such as %lld.
3545     if (Left.is(tok::percent))
3546       return false;
3547     // Preserve the existence of a space before a percent for cases like 0x%04x
3548     // and "%d %d"
3549     if (Left.is(tok::numeric_constant) && Right.is(tok::percent))
3550       return Right.hasWhitespaceBefore();
3551   } else if (Style.isJson()) {
3552     if (Right.is(tok::colon))
3553       return false;
3554   } else if (Style.isCSharp()) {
3555     // Require spaces around '{' and  before '}' unless they appear in
3556     // interpolated strings. Interpolated strings are merged into a single token
3557     // so cannot have spaces inserted by this function.
3558 
3559     // No space between 'this' and '['
3560     if (Left.is(tok::kw_this) && Right.is(tok::l_square))
3561       return false;
3562 
3563     // No space between 'new' and '('
3564     if (Left.is(tok::kw_new) && Right.is(tok::l_paren))
3565       return false;
3566 
3567     // Space before { (including space within '{ {').
3568     if (Right.is(tok::l_brace))
3569       return true;
3570 
3571     // Spaces inside braces.
3572     if (Left.is(tok::l_brace) && Right.isNot(tok::r_brace))
3573       return true;
3574 
3575     if (Left.isNot(tok::l_brace) && Right.is(tok::r_brace))
3576       return true;
3577 
3578     // Spaces around '=>'.
3579     if (Left.is(TT_FatArrow) || Right.is(TT_FatArrow))
3580       return true;
3581 
3582     // No spaces around attribute target colons
3583     if (Left.is(TT_AttributeColon) || Right.is(TT_AttributeColon))
3584       return false;
3585 
3586     // space between type and variable e.g. Dictionary<string,string> foo;
3587     if (Left.is(TT_TemplateCloser) && Right.is(TT_StartOfName))
3588       return true;
3589 
3590     // spaces inside square brackets.
3591     if (Left.is(tok::l_square) || Right.is(tok::r_square))
3592       return Style.SpacesInSquareBrackets;
3593 
3594     // No space before ? in nullable types.
3595     if (Right.is(TT_CSharpNullable))
3596       return false;
3597 
3598     // No space before null forgiving '!'.
3599     if (Right.is(TT_NonNullAssertion))
3600       return false;
3601 
3602     // No space between consecutive commas '[,,]'.
3603     if (Left.is(tok::comma) && Right.is(tok::comma))
3604       return false;
3605 
3606     // space after var in `var (key, value)`
3607     if (Left.is(Keywords.kw_var) && Right.is(tok::l_paren))
3608       return true;
3609 
3610     // space between keywords and paren e.g. "using ("
3611     if (Right.is(tok::l_paren))
3612       if (Left.isOneOf(tok::kw_using, Keywords.kw_async, Keywords.kw_when,
3613                        Keywords.kw_lock))
3614         return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3615                spaceRequiredBeforeParens(Right);
3616 
3617     // space between method modifier and opening parenthesis of a tuple return
3618     // type
3619     if (Left.isOneOf(tok::kw_public, tok::kw_private, tok::kw_protected,
3620                      tok::kw_virtual, tok::kw_extern, tok::kw_static,
3621                      Keywords.kw_internal, Keywords.kw_abstract,
3622                      Keywords.kw_sealed, Keywords.kw_override,
3623                      Keywords.kw_async, Keywords.kw_unsafe) &&
3624         Right.is(tok::l_paren))
3625       return true;
3626   } else if (Style.isJavaScript()) {
3627     if (Left.is(TT_FatArrow))
3628       return true;
3629     // for await ( ...
3630     if (Right.is(tok::l_paren) && Left.is(Keywords.kw_await) && Left.Previous &&
3631         Left.Previous->is(tok::kw_for))
3632       return true;
3633     if (Left.is(Keywords.kw_async) && Right.is(tok::l_paren) &&
3634         Right.MatchingParen) {
3635       const FormatToken *Next = Right.MatchingParen->getNextNonComment();
3636       // An async arrow function, for example: `x = async () => foo();`,
3637       // as opposed to calling a function called async: `x = async();`
3638       if (Next && Next->is(TT_FatArrow))
3639         return true;
3640     }
3641     if ((Left.is(TT_TemplateString) && Left.TokenText.endswith("${")) ||
3642         (Right.is(TT_TemplateString) && Right.TokenText.startswith("}")))
3643       return false;
3644     // In tagged template literals ("html`bar baz`"), there is no space between
3645     // the tag identifier and the template string.
3646     if (Keywords.IsJavaScriptIdentifier(Left,
3647                                         /* AcceptIdentifierName= */ false) &&
3648         Right.is(TT_TemplateString))
3649       return false;
3650     if (Right.is(tok::star) &&
3651         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield))
3652       return false;
3653     if (Right.isOneOf(tok::l_brace, tok::l_square) &&
3654         Left.isOneOf(Keywords.kw_function, Keywords.kw_yield,
3655                      Keywords.kw_extends, Keywords.kw_implements))
3656       return true;
3657     if (Right.is(tok::l_paren)) {
3658       // JS methods can use some keywords as names (e.g. `delete()`).
3659       if (Line.MustBeDeclaration && Left.Tok.getIdentifierInfo())
3660         return false;
3661       // Valid JS method names can include keywords, e.g. `foo.delete()` or
3662       // `bar.instanceof()`. Recognize call positions by preceding period.
3663       if (Left.Previous && Left.Previous->is(tok::period) &&
3664           Left.Tok.getIdentifierInfo())
3665         return false;
3666       // Additional unary JavaScript operators that need a space after.
3667       if (Left.isOneOf(tok::kw_throw, Keywords.kw_await, Keywords.kw_typeof,
3668                        tok::kw_void))
3669         return true;
3670     }
3671     // `foo as const;` casts into a const type.
3672     if (Left.endsSequence(tok::kw_const, Keywords.kw_as))
3673       return false;
3674     if ((Left.isOneOf(Keywords.kw_let, Keywords.kw_var, Keywords.kw_in,
3675                       tok::kw_const) ||
3676          // "of" is only a keyword if it appears after another identifier
3677          // (e.g. as "const x of y" in a for loop), or after a destructuring
3678          // operation (const [x, y] of z, const {a, b} of c).
3679          (Left.is(Keywords.kw_of) && Left.Previous &&
3680           (Left.Previous->is(tok::identifier) ||
3681            Left.Previous->isOneOf(tok::r_square, tok::r_brace)))) &&
3682         (!Left.Previous || !Left.Previous->is(tok::period)))
3683       return true;
3684     if (Left.isOneOf(tok::kw_for, Keywords.kw_as) && Left.Previous &&
3685         Left.Previous->is(tok::period) && Right.is(tok::l_paren))
3686       return false;
3687     if (Left.is(Keywords.kw_as) &&
3688         Right.isOneOf(tok::l_square, tok::l_brace, tok::l_paren))
3689       return true;
3690     if (Left.is(tok::kw_default) && Left.Previous &&
3691         Left.Previous->is(tok::kw_export))
3692       return true;
3693     if (Left.is(Keywords.kw_is) && Right.is(tok::l_brace))
3694       return true;
3695     if (Right.isOneOf(TT_JsTypeColon, TT_JsTypeOptionalQuestion))
3696       return false;
3697     if (Left.is(TT_JsTypeOperator) || Right.is(TT_JsTypeOperator))
3698       return false;
3699     if ((Left.is(tok::l_brace) || Right.is(tok::r_brace)) &&
3700         Line.First->isOneOf(Keywords.kw_import, tok::kw_export))
3701       return false;
3702     if (Left.is(tok::ellipsis))
3703       return false;
3704     if (Left.is(TT_TemplateCloser) &&
3705         !Right.isOneOf(tok::equal, tok::l_brace, tok::comma, tok::l_square,
3706                        Keywords.kw_implements, Keywords.kw_extends))
3707       // Type assertions ('<type>expr') are not followed by whitespace. Other
3708       // locations that should have whitespace following are identified by the
3709       // above set of follower tokens.
3710       return false;
3711     if (Right.is(TT_NonNullAssertion))
3712       return false;
3713     if (Left.is(TT_NonNullAssertion) &&
3714         Right.isOneOf(Keywords.kw_as, Keywords.kw_in))
3715       return true; // "x! as string", "x! in y"
3716   } else if (Style.Language == FormatStyle::LK_Java) {
3717     if (Left.is(tok::r_square) && Right.is(tok::l_brace))
3718       return true;
3719     if (Left.is(Keywords.kw_synchronized) && Right.is(tok::l_paren))
3720       return Style.SpaceBeforeParensOptions.AfterControlStatements ||
3721              spaceRequiredBeforeParens(Right);
3722     if ((Left.isOneOf(tok::kw_static, tok::kw_public, tok::kw_private,
3723                       tok::kw_protected) ||
3724          Left.isOneOf(Keywords.kw_final, Keywords.kw_abstract,
3725                       Keywords.kw_native)) &&
3726         Right.is(TT_TemplateOpener))
3727       return true;
3728   }
3729   if (Left.is(TT_ImplicitStringLiteral))
3730     return Right.hasWhitespaceBefore();
3731   if (Line.Type == LT_ObjCMethodDecl) {
3732     if (Left.is(TT_ObjCMethodSpecifier))
3733       return true;
3734     if (Left.is(tok::r_paren) && canBeObjCSelectorComponent(Right))
3735       // Don't space between ')' and <id> or ')' and 'new'. 'new' is not a
3736       // keyword in Objective-C, and '+ (instancetype)new;' is a standard class
3737       // method declaration.
3738       return false;
3739   }
3740   if (Line.Type == LT_ObjCProperty &&
3741       (Right.is(tok::equal) || Left.is(tok::equal)))
3742     return false;
3743 
3744   if (Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow) ||
3745       Left.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow))
3746     return true;
3747   if (Left.is(tok::comma) && !Right.is(TT_OverloadedOperatorLParen))
3748     return true;
3749   if (Right.is(tok::comma))
3750     return false;
3751   if (Right.is(TT_ObjCBlockLParen))
3752     return true;
3753   if (Right.is(TT_CtorInitializerColon))
3754     return Style.SpaceBeforeCtorInitializerColon;
3755   if (Right.is(TT_InheritanceColon) && !Style.SpaceBeforeInheritanceColon)
3756     return false;
3757   if (Right.is(TT_RangeBasedForLoopColon) &&
3758       !Style.SpaceBeforeRangeBasedForLoopColon)
3759     return false;
3760   if (Left.is(TT_BitFieldColon))
3761     return Style.BitFieldColonSpacing == FormatStyle::BFCS_Both ||
3762            Style.BitFieldColonSpacing == FormatStyle::BFCS_After;
3763   if (Right.is(tok::colon)) {
3764     if (Line.First->isOneOf(tok::kw_default, tok::kw_case))
3765       return Style.SpaceBeforeCaseColon;
3766     const FormatToken *Next = Right.getNextNonComment();
3767     if (!Next || Next->is(tok::semi))
3768       return false;
3769     if (Right.is(TT_ObjCMethodExpr))
3770       return false;
3771     if (Left.is(tok::question))
3772       return false;
3773     if (Right.is(TT_InlineASMColon) && Left.is(tok::coloncolon))
3774       return false;
3775     if (Right.is(TT_DictLiteral))
3776       return Style.SpacesInContainerLiterals;
3777     if (Right.is(TT_AttributeColon))
3778       return false;
3779     if (Right.is(TT_CSharpNamedArgumentColon))
3780       return false;
3781     if (Right.is(TT_BitFieldColon))
3782       return Style.BitFieldColonSpacing == FormatStyle::BFCS_Both ||
3783              Style.BitFieldColonSpacing == FormatStyle::BFCS_Before;
3784     return true;
3785   }
3786   // Do not merge "- -" into "--".
3787   if ((Left.isOneOf(tok::minus, tok::minusminus) &&
3788        Right.isOneOf(tok::minus, tok::minusminus)) ||
3789       (Left.isOneOf(tok::plus, tok::plusplus) &&
3790        Right.isOneOf(tok::plus, tok::plusplus)))
3791     return true;
3792   if (Left.is(TT_UnaryOperator)) {
3793     if (!Right.is(tok::l_paren)) {
3794       // The alternative operators for ~ and ! are "compl" and "not".
3795       // If they are used instead, we do not want to combine them with
3796       // the token to the right, unless that is a left paren.
3797       if (Left.is(tok::exclaim) && Left.TokenText == "not")
3798         return true;
3799       if (Left.is(tok::tilde) && Left.TokenText == "compl")
3800         return true;
3801       // Lambda captures allow for a lone &, so "&]" needs to be properly
3802       // handled.
3803       if (Left.is(tok::amp) && Right.is(tok::r_square))
3804         return Style.SpacesInSquareBrackets;
3805     }
3806     return (Style.SpaceAfterLogicalNot && Left.is(tok::exclaim)) ||
3807            Right.is(TT_BinaryOperator);
3808   }
3809 
3810   // If the next token is a binary operator or a selector name, we have
3811   // incorrectly classified the parenthesis as a cast. FIXME: Detect correctly.
3812   if (Left.is(TT_CastRParen))
3813     return Style.SpaceAfterCStyleCast ||
3814            Right.isOneOf(TT_BinaryOperator, TT_SelectorName);
3815 
3816   auto ShouldAddSpacesInAngles = [this, &Right]() {
3817     if (this->Style.SpacesInAngles == FormatStyle::SIAS_Always)
3818       return true;
3819     if (this->Style.SpacesInAngles == FormatStyle::SIAS_Leave)
3820       return Right.hasWhitespaceBefore();
3821     return false;
3822   };
3823 
3824   if (Left.is(tok::greater) && Right.is(tok::greater)) {
3825     if (Style.Language == FormatStyle::LK_TextProto ||
3826         (Style.Language == FormatStyle::LK_Proto && Left.is(TT_DictLiteral)))
3827       return !Style.Cpp11BracedListStyle;
3828     return Right.is(TT_TemplateCloser) && Left.is(TT_TemplateCloser) &&
3829            ((Style.Standard < FormatStyle::LS_Cpp11) ||
3830             ShouldAddSpacesInAngles());
3831   }
3832   if (Right.isOneOf(tok::arrow, tok::arrowstar, tok::periodstar) ||
3833       Left.isOneOf(tok::arrow, tok::period, tok::arrowstar, tok::periodstar) ||
3834       (Right.is(tok::period) && Right.isNot(TT_DesignatedInitializerPeriod)))
3835     return false;
3836   if (!Style.SpaceBeforeAssignmentOperators && Left.isNot(TT_TemplateCloser) &&
3837       Right.getPrecedence() == prec::Assignment)
3838     return false;
3839   if (Style.Language == FormatStyle::LK_Java && Right.is(tok::coloncolon) &&
3840       (Left.is(tok::identifier) || Left.is(tok::kw_this)))
3841     return false;
3842   if (Right.is(tok::coloncolon) && Left.is(tok::identifier))
3843     // Generally don't remove existing spaces between an identifier and "::".
3844     // The identifier might actually be a macro name such as ALWAYS_INLINE. If
3845     // this turns out to be too lenient, add analysis of the identifier itself.
3846     return Right.hasWhitespaceBefore();
3847   if (Right.is(tok::coloncolon) &&
3848       !Left.isOneOf(tok::l_brace, tok::comment, tok::l_paren))
3849     // Put a space between < and :: in vector< ::std::string >
3850     return (Left.is(TT_TemplateOpener) &&
3851             ((Style.Standard < FormatStyle::LS_Cpp11) ||
3852              ShouldAddSpacesInAngles())) ||
3853            !(Left.isOneOf(tok::l_paren, tok::r_paren, tok::l_square,
3854                           tok::kw___super, TT_TemplateOpener,
3855                           TT_TemplateCloser)) ||
3856            (Left.is(tok::l_paren) && Style.SpacesInParentheses);
3857   if ((Left.is(TT_TemplateOpener)) != (Right.is(TT_TemplateCloser)))
3858     return ShouldAddSpacesInAngles();
3859   // Space before TT_StructuredBindingLSquare.
3860   if (Right.is(TT_StructuredBindingLSquare))
3861     return !Left.isOneOf(tok::amp, tok::ampamp) ||
3862            getTokenReferenceAlignment(Left) != FormatStyle::PAS_Right;
3863   // Space before & or && following a TT_StructuredBindingLSquare.
3864   if (Right.Next && Right.Next->is(TT_StructuredBindingLSquare) &&
3865       Right.isOneOf(tok::amp, tok::ampamp))
3866     return getTokenReferenceAlignment(Right) != FormatStyle::PAS_Left;
3867   if ((Right.is(TT_BinaryOperator) && !Left.is(tok::l_paren)) ||
3868       (Left.isOneOf(TT_BinaryOperator, TT_ConditionalExpr) &&
3869        !Right.is(tok::r_paren)))
3870     return true;
3871   if (Right.is(TT_TemplateOpener) && Left.is(tok::r_paren) &&
3872       Left.MatchingParen && Left.MatchingParen->is(TT_OverloadedOperatorLParen))
3873     return false;
3874   if (Right.is(tok::less) && Left.isNot(tok::l_paren) &&
3875       Line.startsWith(tok::hash))
3876     return true;
3877   if (Right.is(TT_TrailingUnaryOperator))
3878     return false;
3879   if (Left.is(TT_RegexLiteral))
3880     return false;
3881   return spaceRequiredBetween(Line, Left, Right);
3882 }
3883 
3884 // Returns 'true' if 'Tok' is a brace we'd want to break before in Allman style.
3885 static bool isAllmanBrace(const FormatToken &Tok) {
3886   return Tok.is(tok::l_brace) && Tok.is(BK_Block) &&
3887          !Tok.isOneOf(TT_ObjCBlockLBrace, TT_LambdaLBrace, TT_DictLiteral);
3888 }
3889 
3890 // Returns 'true' if 'Tok' is a function argument.
3891 static bool IsFunctionArgument(const FormatToken &Tok) {
3892   return Tok.MatchingParen && Tok.MatchingParen->Next &&
3893          Tok.MatchingParen->Next->isOneOf(tok::comma, tok::r_paren);
3894 }
3895 
3896 static bool
3897 isItAnEmptyLambdaAllowed(const FormatToken &Tok,
3898                          FormatStyle::ShortLambdaStyle ShortLambdaOption) {
3899   return Tok.Children.empty() && ShortLambdaOption != FormatStyle::SLS_None;
3900 }
3901 
3902 static bool isAllmanLambdaBrace(const FormatToken &Tok) {
3903   return Tok.is(tok::l_brace) && Tok.is(BK_Block) &&
3904          !Tok.isOneOf(TT_ObjCBlockLBrace, TT_DictLiteral);
3905 }
3906 
3907 // Returns the first token on the line that is not a comment.
3908 static const FormatToken *getFirstNonComment(const AnnotatedLine &Line) {
3909   const FormatToken *Next = Line.First;
3910   if (!Next)
3911     return Next;
3912   if (Next->is(tok::comment))
3913     Next = Next->getNextNonComment();
3914   return Next;
3915 }
3916 
3917 bool TokenAnnotator::mustBreakBefore(const AnnotatedLine &Line,
3918                                      const FormatToken &Right) {
3919   const FormatToken &Left = *Right.Previous;
3920   if (Right.NewlinesBefore > 1 && Style.MaxEmptyLinesToKeep > 0)
3921     return true;
3922 
3923   if (Style.isCSharp()) {
3924     if (Left.is(TT_FatArrow) && Right.is(tok::l_brace) &&
3925         Style.BraceWrapping.AfterFunction)
3926       return true;
3927     if (Right.is(TT_CSharpNamedArgumentColon) ||
3928         Left.is(TT_CSharpNamedArgumentColon))
3929       return false;
3930     if (Right.is(TT_CSharpGenericTypeConstraint))
3931       return true;
3932     if (Right.Next && Right.Next->is(TT_FatArrow) &&
3933         (Right.is(tok::numeric_constant) ||
3934          (Right.is(tok::identifier) && Right.TokenText == "_")))
3935       return true;
3936 
3937     // Break after C# [...] and before public/protected/private/internal.
3938     if (Left.is(TT_AttributeSquare) && Left.is(tok::r_square) &&
3939         (Right.isAccessSpecifier(/*ColonRequired=*/false) ||
3940          Right.is(Keywords.kw_internal)))
3941       return true;
3942     // Break between ] and [ but only when there are really 2 attributes.
3943     if (Left.is(TT_AttributeSquare) && Right.is(TT_AttributeSquare) &&
3944         Left.is(tok::r_square) && Right.is(tok::l_square))
3945       return true;
3946 
3947   } else if (Style.isJavaScript()) {
3948     // FIXME: This might apply to other languages and token kinds.
3949     if (Right.is(tok::string_literal) && Left.is(tok::plus) && Left.Previous &&
3950         Left.Previous->is(tok::string_literal))
3951       return true;
3952     if (Left.is(TT_DictLiteral) && Left.is(tok::l_brace) && Line.Level == 0 &&
3953         Left.Previous && Left.Previous->is(tok::equal) &&
3954         Line.First->isOneOf(tok::identifier, Keywords.kw_import, tok::kw_export,
3955                             tok::kw_const) &&
3956         // kw_var/kw_let are pseudo-tokens that are tok::identifier, so match
3957         // above.
3958         !Line.First->isOneOf(Keywords.kw_var, Keywords.kw_let))
3959       // Object literals on the top level of a file are treated as "enum-style".
3960       // Each key/value pair is put on a separate line, instead of bin-packing.
3961       return true;
3962     if (Left.is(tok::l_brace) && Line.Level == 0 &&
3963         (Line.startsWith(tok::kw_enum) ||
3964          Line.startsWith(tok::kw_const, tok::kw_enum) ||
3965          Line.startsWith(tok::kw_export, tok::kw_enum) ||
3966          Line.startsWith(tok::kw_export, tok::kw_const, tok::kw_enum)))
3967       // JavaScript top-level enum key/value pairs are put on separate lines
3968       // instead of bin-packing.
3969       return true;
3970     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) && Left.Previous &&
3971         Left.Previous->is(TT_FatArrow)) {
3972       // JS arrow function (=> {...}).
3973       switch (Style.AllowShortLambdasOnASingleLine) {
3974       case FormatStyle::SLS_All:
3975         return false;
3976       case FormatStyle::SLS_None:
3977         return true;
3978       case FormatStyle::SLS_Empty:
3979         return !Left.Children.empty();
3980       case FormatStyle::SLS_Inline:
3981         // allow one-lining inline (e.g. in function call args) and empty arrow
3982         // functions.
3983         return (Left.NestingLevel == 0 && Line.Level == 0) &&
3984                !Left.Children.empty();
3985       }
3986       llvm_unreachable("Unknown FormatStyle::ShortLambdaStyle enum");
3987     }
3988 
3989     if (Right.is(tok::r_brace) && Left.is(tok::l_brace) &&
3990         !Left.Children.empty())
3991       // Support AllowShortFunctionsOnASingleLine for JavaScript.
3992       return Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_None ||
3993              Style.AllowShortFunctionsOnASingleLine == FormatStyle::SFS_Empty ||
3994              (Left.NestingLevel == 0 && Line.Level == 0 &&
3995               Style.AllowShortFunctionsOnASingleLine &
3996                   FormatStyle::SFS_InlineOnly);
3997   } else if (Style.Language == FormatStyle::LK_Java) {
3998     if (Right.is(tok::plus) && Left.is(tok::string_literal) && Right.Next &&
3999         Right.Next->is(tok::string_literal))
4000       return true;
4001   } else if (Style.Language == FormatStyle::LK_Cpp ||
4002              Style.Language == FormatStyle::LK_ObjC ||
4003              Style.Language == FormatStyle::LK_Proto ||
4004              Style.Language == FormatStyle::LK_TableGen ||
4005              Style.Language == FormatStyle::LK_TextProto) {
4006     if (Left.isStringLiteral() && Right.isStringLiteral())
4007       return true;
4008   }
4009 
4010   // Basic JSON newline processing.
4011   if (Style.isJson()) {
4012     // Always break after a JSON record opener.
4013     // {
4014     // }
4015     if (Left.is(TT_DictLiteral) && Left.is(tok::l_brace))
4016       return true;
4017     // Always break after a JSON array opener.
4018     // [
4019     // ]
4020     if (Left.is(TT_ArrayInitializerLSquare) && Left.is(tok::l_square) &&
4021         !Right.is(tok::r_square))
4022       return true;
4023     // Always break after successive entries.
4024     // 1,
4025     // 2
4026     if (Left.is(tok::comma))
4027       return true;
4028   }
4029 
4030   // If the last token before a '}', ']', or ')' is a comma or a trailing
4031   // comment, the intention is to insert a line break after it in order to make
4032   // shuffling around entries easier. Import statements, especially in
4033   // JavaScript, can be an exception to this rule.
4034   if (Style.JavaScriptWrapImports || Line.Type != LT_ImportStatement) {
4035     const FormatToken *BeforeClosingBrace = nullptr;
4036     if ((Left.isOneOf(tok::l_brace, TT_ArrayInitializerLSquare) ||
4037          (Style.isJavaScript() && Left.is(tok::l_paren))) &&
4038         Left.isNot(BK_Block) && Left.MatchingParen)
4039       BeforeClosingBrace = Left.MatchingParen->Previous;
4040     else if (Right.MatchingParen &&
4041              (Right.MatchingParen->isOneOf(tok::l_brace,
4042                                            TT_ArrayInitializerLSquare) ||
4043               (Style.isJavaScript() && Right.MatchingParen->is(tok::l_paren))))
4044       BeforeClosingBrace = &Left;
4045     if (BeforeClosingBrace && (BeforeClosingBrace->is(tok::comma) ||
4046                                BeforeClosingBrace->isTrailingComment()))
4047       return true;
4048   }
4049 
4050   if (Right.is(tok::comment))
4051     return Left.isNot(BK_BracedInit) && Left.isNot(TT_CtorInitializerColon) &&
4052            (Right.NewlinesBefore > 0 && Right.HasUnescapedNewline);
4053   if (Left.isTrailingComment())
4054     return true;
4055   if (Left.IsUnterminatedLiteral)
4056     return true;
4057   if (Right.is(tok::lessless) && Right.Next && Left.is(tok::string_literal) &&
4058       Right.Next->is(tok::string_literal))
4059     return true;
4060   if (Right.is(TT_RequiresClause)) {
4061     switch (Style.RequiresClausePosition) {
4062     case FormatStyle::RCPS_OwnLine:
4063     case FormatStyle::RCPS_WithFollowing:
4064       return true;
4065     default:
4066       break;
4067     }
4068   }
4069   // Can break after template<> declaration
4070   if (Left.ClosesTemplateDeclaration && Left.MatchingParen &&
4071       Left.MatchingParen->NestingLevel == 0) {
4072     // Put concepts on the next line e.g.
4073     // template<typename T>
4074     // concept ...
4075     if (Right.is(tok::kw_concept))
4076       return Style.BreakBeforeConceptDeclarations == FormatStyle::BBCDS_Always;
4077     return Style.AlwaysBreakTemplateDeclarations == FormatStyle::BTDS_Yes;
4078   }
4079   if (Left.ClosesRequiresClause && Right.isNot(tok::semi)) {
4080     switch (Style.RequiresClausePosition) {
4081     case FormatStyle::RCPS_OwnLine:
4082     case FormatStyle::RCPS_WithPreceding:
4083       return true;
4084     default:
4085       break;
4086     }
4087   }
4088   if (Style.PackConstructorInitializers == FormatStyle::PCIS_Never) {
4089     if (Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeColon &&
4090         (Left.is(TT_CtorInitializerComma) || Right.is(TT_CtorInitializerColon)))
4091       return true;
4092 
4093     if (Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon &&
4094         Left.isOneOf(TT_CtorInitializerColon, TT_CtorInitializerComma))
4095       return true;
4096   }
4097   if (Style.PackConstructorInitializers < FormatStyle::PCIS_CurrentLine &&
4098       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma &&
4099       Right.isOneOf(TT_CtorInitializerComma, TT_CtorInitializerColon))
4100     return true;
4101   // Break only if we have multiple inheritance.
4102   if (Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma &&
4103       Right.is(TT_InheritanceComma))
4104     return true;
4105   if (Style.BreakInheritanceList == FormatStyle::BILS_AfterComma &&
4106       Left.is(TT_InheritanceComma))
4107     return true;
4108   if (Right.is(tok::string_literal) && Right.TokenText.startswith("R\""))
4109     // Multiline raw string literals are special wrt. line breaks. The author
4110     // has made a deliberate choice and might have aligned the contents of the
4111     // string literal accordingly. Thus, we try keep existing line breaks.
4112     return Right.IsMultiline && Right.NewlinesBefore > 0;
4113   if ((Left.is(tok::l_brace) || (Left.is(tok::less) && Left.Previous &&
4114                                  Left.Previous->is(tok::equal))) &&
4115       Right.NestingLevel == 1 && Style.Language == FormatStyle::LK_Proto) {
4116     // Don't put enums or option definitions onto single lines in protocol
4117     // buffers.
4118     return true;
4119   }
4120   if (Right.is(TT_InlineASMBrace))
4121     return Right.HasUnescapedNewline;
4122 
4123   if (isAllmanBrace(Left) || isAllmanBrace(Right)) {
4124     auto FirstNonComment = getFirstNonComment(Line);
4125     bool AccessSpecifier =
4126         FirstNonComment &&
4127         FirstNonComment->isOneOf(Keywords.kw_internal, tok::kw_public,
4128                                  tok::kw_private, tok::kw_protected);
4129 
4130     if (Style.BraceWrapping.AfterEnum) {
4131       if (Line.startsWith(tok::kw_enum) ||
4132           Line.startsWith(tok::kw_typedef, tok::kw_enum))
4133         return true;
4134       // Ensure BraceWrapping for `public enum A {`.
4135       if (AccessSpecifier && FirstNonComment->Next &&
4136           FirstNonComment->Next->is(tok::kw_enum))
4137         return true;
4138     }
4139 
4140     // Ensure BraceWrapping for `public interface A {`.
4141     if (Style.BraceWrapping.AfterClass &&
4142         ((AccessSpecifier && FirstNonComment->Next &&
4143           FirstNonComment->Next->is(Keywords.kw_interface)) ||
4144          Line.startsWith(Keywords.kw_interface)))
4145       return true;
4146 
4147     return (Line.startsWith(tok::kw_class) && Style.BraceWrapping.AfterClass) ||
4148            (Line.startsWith(tok::kw_struct) && Style.BraceWrapping.AfterStruct);
4149   }
4150 
4151   if (Left.is(TT_ObjCBlockLBrace) &&
4152       Style.AllowShortBlocksOnASingleLine == FormatStyle::SBS_Never)
4153     return true;
4154 
4155   // Ensure wrapping after __attribute__((XX)) and @interface etc.
4156   if (Left.is(TT_AttributeParen) && Right.is(TT_ObjCDecl))
4157     return true;
4158 
4159   if (Left.is(TT_LambdaLBrace)) {
4160     if (IsFunctionArgument(Left) &&
4161         Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_Inline)
4162       return false;
4163 
4164     if (Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_None ||
4165         Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_Inline ||
4166         (!Left.Children.empty() &&
4167          Style.AllowShortLambdasOnASingleLine == FormatStyle::SLS_Empty))
4168       return true;
4169   }
4170 
4171   if (Style.BraceWrapping.BeforeLambdaBody && Right.is(TT_LambdaLBrace) &&
4172       Left.isOneOf(tok::star, tok::amp, tok::ampamp, TT_TemplateCloser))
4173     return true;
4174 
4175   // Put multiple Java annotation on a new line.
4176   if ((Style.Language == FormatStyle::LK_Java || Style.isJavaScript()) &&
4177       Left.is(TT_LeadingJavaAnnotation) &&
4178       Right.isNot(TT_LeadingJavaAnnotation) && Right.isNot(tok::l_paren) &&
4179       (Line.Last->is(tok::l_brace) || Style.BreakAfterJavaFieldAnnotations))
4180     return true;
4181 
4182   if (Right.is(TT_ProtoExtensionLSquare))
4183     return true;
4184 
4185   // In text proto instances if a submessage contains at least 2 entries and at
4186   // least one of them is a submessage, like A { ... B { ... } ... },
4187   // put all of the entries of A on separate lines by forcing the selector of
4188   // the submessage B to be put on a newline.
4189   //
4190   // Example: these can stay on one line:
4191   // a { scalar_1: 1 scalar_2: 2 }
4192   // a { b { key: value } }
4193   //
4194   // and these entries need to be on a new line even if putting them all in one
4195   // line is under the column limit:
4196   // a {
4197   //   scalar: 1
4198   //   b { key: value }
4199   // }
4200   //
4201   // We enforce this by breaking before a submessage field that has previous
4202   // siblings, *and* breaking before a field that follows a submessage field.
4203   //
4204   // Be careful to exclude the case  [proto.ext] { ... } since the `]` is
4205   // the TT_SelectorName there, but we don't want to break inside the brackets.
4206   //
4207   // Another edge case is @submessage { key: value }, which is a common
4208   // substitution placeholder. In this case we want to keep `@` and `submessage`
4209   // together.
4210   //
4211   // We ensure elsewhere that extensions are always on their own line.
4212   if ((Style.Language == FormatStyle::LK_Proto ||
4213        Style.Language == FormatStyle::LK_TextProto) &&
4214       Right.is(TT_SelectorName) && !Right.is(tok::r_square) && Right.Next) {
4215     // Keep `@submessage` together in:
4216     // @submessage { key: value }
4217     if (Left.is(tok::at))
4218       return false;
4219     // Look for the scope opener after selector in cases like:
4220     // selector { ...
4221     // selector: { ...
4222     // selector: @base { ...
4223     FormatToken *LBrace = Right.Next;
4224     if (LBrace && LBrace->is(tok::colon)) {
4225       LBrace = LBrace->Next;
4226       if (LBrace && LBrace->is(tok::at)) {
4227         LBrace = LBrace->Next;
4228         if (LBrace)
4229           LBrace = LBrace->Next;
4230       }
4231     }
4232     if (LBrace &&
4233         // The scope opener is one of {, [, <:
4234         // selector { ... }
4235         // selector [ ... ]
4236         // selector < ... >
4237         //
4238         // In case of selector { ... }, the l_brace is TT_DictLiteral.
4239         // In case of an empty selector {}, the l_brace is not TT_DictLiteral,
4240         // so we check for immediately following r_brace.
4241         ((LBrace->is(tok::l_brace) &&
4242           (LBrace->is(TT_DictLiteral) ||
4243            (LBrace->Next && LBrace->Next->is(tok::r_brace)))) ||
4244          LBrace->is(TT_ArrayInitializerLSquare) || LBrace->is(tok::less))) {
4245       // If Left.ParameterCount is 0, then this submessage entry is not the
4246       // first in its parent submessage, and we want to break before this entry.
4247       // If Left.ParameterCount is greater than 0, then its parent submessage
4248       // might contain 1 or more entries and we want to break before this entry
4249       // if it contains at least 2 entries. We deal with this case later by
4250       // detecting and breaking before the next entry in the parent submessage.
4251       if (Left.ParameterCount == 0)
4252         return true;
4253       // However, if this submessage is the first entry in its parent
4254       // submessage, Left.ParameterCount might be 1 in some cases.
4255       // We deal with this case later by detecting an entry
4256       // following a closing paren of this submessage.
4257     }
4258 
4259     // If this is an entry immediately following a submessage, it will be
4260     // preceded by a closing paren of that submessage, like in:
4261     //     left---.  .---right
4262     //            v  v
4263     // sub: { ... } key: value
4264     // If there was a comment between `}` an `key` above, then `key` would be
4265     // put on a new line anyways.
4266     if (Left.isOneOf(tok::r_brace, tok::greater, tok::r_square))
4267       return true;
4268   }
4269 
4270   // Deal with lambda arguments in C++ - we want consistent line breaks whether
4271   // they happen to be at arg0, arg1 or argN. The selection is a bit nuanced
4272   // as aggressive line breaks are placed when the lambda is not the last arg.
4273   if ((Style.Language == FormatStyle::LK_Cpp ||
4274        Style.Language == FormatStyle::LK_ObjC) &&
4275       Left.is(tok::l_paren) && Left.BlockParameterCount > 0 &&
4276       !Right.isOneOf(tok::l_paren, TT_LambdaLSquare)) {
4277     // Multiple lambdas in the same function call force line breaks.
4278     if (Left.BlockParameterCount > 1)
4279       return true;
4280 
4281     // A lambda followed by another arg forces a line break.
4282     if (!Left.Role)
4283       return false;
4284     auto Comma = Left.Role->lastComma();
4285     if (!Comma)
4286       return false;
4287     auto Next = Comma->getNextNonComment();
4288     if (!Next)
4289       return false;
4290     if (!Next->isOneOf(TT_LambdaLSquare, tok::l_brace, tok::caret))
4291       return true;
4292   }
4293 
4294   return false;
4295 }
4296 
4297 bool TokenAnnotator::canBreakBefore(const AnnotatedLine &Line,
4298                                     const FormatToken &Right) {
4299   const FormatToken &Left = *Right.Previous;
4300   // Language-specific stuff.
4301   if (Style.isCSharp()) {
4302     if (Left.isOneOf(TT_CSharpNamedArgumentColon, TT_AttributeColon) ||
4303         Right.isOneOf(TT_CSharpNamedArgumentColon, TT_AttributeColon))
4304       return false;
4305     // Only break after commas for generic type constraints.
4306     if (Line.First->is(TT_CSharpGenericTypeConstraint))
4307       return Left.is(TT_CSharpGenericTypeConstraintComma);
4308     // Keep nullable operators attached to their identifiers.
4309     if (Right.is(TT_CSharpNullable))
4310       return false;
4311   } else if (Style.Language == FormatStyle::LK_Java) {
4312     if (Left.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
4313                      Keywords.kw_implements))
4314       return false;
4315     if (Right.isOneOf(Keywords.kw_throws, Keywords.kw_extends,
4316                       Keywords.kw_implements))
4317       return true;
4318   } else if (Style.isJavaScript()) {
4319     const FormatToken *NonComment = Right.getPreviousNonComment();
4320     if (NonComment &&
4321         NonComment->isOneOf(
4322             tok::kw_return, Keywords.kw_yield, tok::kw_continue, tok::kw_break,
4323             tok::kw_throw, Keywords.kw_interface, Keywords.kw_type,
4324             tok::kw_static, tok::kw_public, tok::kw_private, tok::kw_protected,
4325             Keywords.kw_readonly, Keywords.kw_override, Keywords.kw_abstract,
4326             Keywords.kw_get, Keywords.kw_set, Keywords.kw_async,
4327             Keywords.kw_await))
4328       return false; // Otherwise automatic semicolon insertion would trigger.
4329     if (Right.NestingLevel == 0 &&
4330         (Left.Tok.getIdentifierInfo() ||
4331          Left.isOneOf(tok::r_square, tok::r_paren)) &&
4332         Right.isOneOf(tok::l_square, tok::l_paren))
4333       return false; // Otherwise automatic semicolon insertion would trigger.
4334     if (NonComment && NonComment->is(tok::identifier) &&
4335         NonComment->TokenText == "asserts")
4336       return false;
4337     if (Left.is(TT_FatArrow) && Right.is(tok::l_brace))
4338       return false;
4339     if (Left.is(TT_JsTypeColon))
4340       return true;
4341     // Don't wrap between ":" and "!" of a strict prop init ("field!: type;").
4342     if (Left.is(tok::exclaim) && Right.is(tok::colon))
4343       return false;
4344     // Look for is type annotations like:
4345     // function f(): a is B { ... }
4346     // Do not break before is in these cases.
4347     if (Right.is(Keywords.kw_is)) {
4348       const FormatToken *Next = Right.getNextNonComment();
4349       // If `is` is followed by a colon, it's likely that it's a dict key, so
4350       // ignore it for this check.
4351       // For example this is common in Polymer:
4352       // Polymer({
4353       //   is: 'name',
4354       //   ...
4355       // });
4356       if (!Next || !Next->is(tok::colon))
4357         return false;
4358     }
4359     if (Left.is(Keywords.kw_in))
4360       return Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None;
4361     if (Right.is(Keywords.kw_in))
4362       return Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None;
4363     if (Right.is(Keywords.kw_as))
4364       return false; // must not break before as in 'x as type' casts
4365     if (Right.isOneOf(Keywords.kw_extends, Keywords.kw_infer)) {
4366       // extends and infer can appear as keywords in conditional types:
4367       //   https://www.typescriptlang.org/docs/handbook/release-notes/typescript-2-8.html#conditional-types
4368       // do not break before them, as the expressions are subject to ASI.
4369       return false;
4370     }
4371     if (Left.is(Keywords.kw_as))
4372       return true;
4373     if (Left.is(TT_NonNullAssertion))
4374       return true;
4375     if (Left.is(Keywords.kw_declare) &&
4376         Right.isOneOf(Keywords.kw_module, tok::kw_namespace,
4377                       Keywords.kw_function, tok::kw_class, tok::kw_enum,
4378                       Keywords.kw_interface, Keywords.kw_type, Keywords.kw_var,
4379                       Keywords.kw_let, tok::kw_const))
4380       // See grammar for 'declare' statements at:
4381       // https://github.com/Microsoft/TypeScript/blob/main/doc/spec-ARCHIVED.md#A.10
4382       return false;
4383     if (Left.isOneOf(Keywords.kw_module, tok::kw_namespace) &&
4384         Right.isOneOf(tok::identifier, tok::string_literal))
4385       return false; // must not break in "module foo { ...}"
4386     if (Right.is(TT_TemplateString) && Right.closesScope())
4387       return false;
4388     // Don't split tagged template literal so there is a break between the tag
4389     // identifier and template string.
4390     if (Left.is(tok::identifier) && Right.is(TT_TemplateString))
4391       return false;
4392     if (Left.is(TT_TemplateString) && Left.opensScope())
4393       return true;
4394   }
4395 
4396   if (Left.is(tok::at))
4397     return false;
4398   if (Left.Tok.getObjCKeywordID() == tok::objc_interface)
4399     return false;
4400   if (Left.isOneOf(TT_JavaAnnotation, TT_LeadingJavaAnnotation))
4401     return !Right.is(tok::l_paren);
4402   if (Right.is(TT_PointerOrReference))
4403     return Line.IsMultiVariableDeclStmt ||
4404            (getTokenPointerOrReferenceAlignment(Right) ==
4405                 FormatStyle::PAS_Right &&
4406             (!Right.Next || Right.Next->isNot(TT_FunctionDeclarationName)));
4407   if (Right.isOneOf(TT_StartOfName, TT_FunctionDeclarationName) ||
4408       Right.is(tok::kw_operator))
4409     return true;
4410   if (Left.is(TT_PointerOrReference))
4411     return false;
4412   if (Right.isTrailingComment())
4413     // We rely on MustBreakBefore being set correctly here as we should not
4414     // change the "binding" behavior of a comment.
4415     // The first comment in a braced lists is always interpreted as belonging to
4416     // the first list element. Otherwise, it should be placed outside of the
4417     // list.
4418     return Left.is(BK_BracedInit) ||
4419            (Left.is(TT_CtorInitializerColon) &&
4420             Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon);
4421   if (Left.is(tok::question) && Right.is(tok::colon))
4422     return false;
4423   if (Right.is(TT_ConditionalExpr) || Right.is(tok::question))
4424     return Style.BreakBeforeTernaryOperators;
4425   if (Left.is(TT_ConditionalExpr) || Left.is(tok::question))
4426     return !Style.BreakBeforeTernaryOperators;
4427   if (Left.is(TT_InheritanceColon))
4428     return Style.BreakInheritanceList == FormatStyle::BILS_AfterColon;
4429   if (Right.is(TT_InheritanceColon))
4430     return Style.BreakInheritanceList != FormatStyle::BILS_AfterColon;
4431   if (Right.is(TT_ObjCMethodExpr) && !Right.is(tok::r_square) &&
4432       Left.isNot(TT_SelectorName))
4433     return true;
4434 
4435   if (Right.is(tok::colon) &&
4436       !Right.isOneOf(TT_CtorInitializerColon, TT_InlineASMColon))
4437     return false;
4438   if (Left.is(tok::colon) && Left.isOneOf(TT_DictLiteral, TT_ObjCMethodExpr)) {
4439     if (Style.Language == FormatStyle::LK_Proto ||
4440         Style.Language == FormatStyle::LK_TextProto) {
4441       if (!Style.AlwaysBreakBeforeMultilineStrings && Right.isStringLiteral())
4442         return false;
4443       // Prevent cases like:
4444       //
4445       // submessage:
4446       //     { key: valueeeeeeeeeeee }
4447       //
4448       // when the snippet does not fit into one line.
4449       // Prefer:
4450       //
4451       // submessage: {
4452       //   key: valueeeeeeeeeeee
4453       // }
4454       //
4455       // instead, even if it is longer by one line.
4456       //
4457       // Note that this allows allows the "{" to go over the column limit
4458       // when the column limit is just between ":" and "{", but that does
4459       // not happen too often and alternative formattings in this case are
4460       // not much better.
4461       //
4462       // The code covers the cases:
4463       //
4464       // submessage: { ... }
4465       // submessage: < ... >
4466       // repeated: [ ... ]
4467       if (((Right.is(tok::l_brace) || Right.is(tok::less)) &&
4468            Right.is(TT_DictLiteral)) ||
4469           Right.is(TT_ArrayInitializerLSquare))
4470         return false;
4471     }
4472     return true;
4473   }
4474   if (Right.is(tok::r_square) && Right.MatchingParen &&
4475       Right.MatchingParen->is(TT_ProtoExtensionLSquare))
4476     return false;
4477   if (Right.is(TT_SelectorName) || (Right.is(tok::identifier) && Right.Next &&
4478                                     Right.Next->is(TT_ObjCMethodExpr)))
4479     return Left.isNot(tok::period); // FIXME: Properly parse ObjC calls.
4480   if (Left.is(tok::r_paren) && Line.Type == LT_ObjCProperty)
4481     return true;
4482   if (Right.is(tok::kw_concept))
4483     return Style.BreakBeforeConceptDeclarations != FormatStyle::BBCDS_Never;
4484   if (Right.is(TT_RequiresClause))
4485     return true;
4486   if (Left.ClosesTemplateDeclaration || Left.is(TT_FunctionAnnotationRParen))
4487     return true;
4488   if (Left.ClosesRequiresClause)
4489     return true;
4490   if (Right.isOneOf(TT_RangeBasedForLoopColon, TT_OverloadedOperatorLParen,
4491                     TT_OverloadedOperator))
4492     return false;
4493   if (Left.is(TT_RangeBasedForLoopColon))
4494     return true;
4495   if (Right.is(TT_RangeBasedForLoopColon))
4496     return false;
4497   if (Left.is(TT_TemplateCloser) && Right.is(TT_TemplateOpener))
4498     return true;
4499   if ((Left.is(tok::greater) && Right.is(tok::greater)) ||
4500       (Left.is(tok::less) && Right.is(tok::less)))
4501     return false;
4502   if (Right.is(TT_BinaryOperator) &&
4503       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_None &&
4504       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_All ||
4505        Right.getPrecedence() != prec::Assignment))
4506     return true;
4507   if (Left.isOneOf(TT_TemplateCloser, TT_UnaryOperator) ||
4508       Left.is(tok::kw_operator))
4509     return false;
4510   if (Left.is(tok::equal) && !Right.isOneOf(tok::kw_default, tok::kw_delete) &&
4511       Line.Type == LT_VirtualFunctionDecl && Left.NestingLevel == 0)
4512     return false;
4513   if (Left.is(tok::equal) && Right.is(tok::l_brace) &&
4514       !Style.Cpp11BracedListStyle)
4515     return false;
4516   if (Left.is(tok::l_paren) &&
4517       Left.isOneOf(TT_AttributeParen, TT_TypeDeclarationParen))
4518     return false;
4519   if (Left.is(tok::l_paren) && Left.Previous &&
4520       (Left.Previous->isOneOf(TT_BinaryOperator, TT_CastRParen)))
4521     return false;
4522   if (Right.is(TT_ImplicitStringLiteral))
4523     return false;
4524 
4525   if (Right.is(TT_TemplateCloser))
4526     return false;
4527   if (Right.is(tok::r_square) && Right.MatchingParen &&
4528       Right.MatchingParen->is(TT_LambdaLSquare))
4529     return false;
4530 
4531   // We only break before r_brace if there was a corresponding break before
4532   // the l_brace, which is tracked by BreakBeforeClosingBrace.
4533   if (Right.is(tok::r_brace))
4534     return Right.MatchingParen && Right.MatchingParen->is(BK_Block);
4535 
4536   // We only break before r_paren if we're in a block indented context.
4537   if (Right.is(tok::r_paren)) {
4538     if (Style.AlignAfterOpenBracket != FormatStyle::BAS_BlockIndent ||
4539         !Right.MatchingParen)
4540       return false;
4541     const FormatToken *Previous = Right.MatchingParen->Previous;
4542     return !(Previous && (Previous->is(tok::kw_for) || Previous->isIf()));
4543   }
4544 
4545   // Allow breaking after a trailing annotation, e.g. after a method
4546   // declaration.
4547   if (Left.is(TT_TrailingAnnotation))
4548     return !Right.isOneOf(tok::l_brace, tok::semi, tok::equal, tok::l_paren,
4549                           tok::less, tok::coloncolon);
4550 
4551   if (Right.is(tok::kw___attribute) ||
4552       (Right.is(tok::l_square) && Right.is(TT_AttributeSquare)))
4553     return !Left.is(TT_AttributeSquare);
4554 
4555   if (Left.is(tok::identifier) && Right.is(tok::string_literal))
4556     return true;
4557 
4558   if (Right.is(tok::identifier) && Right.Next && Right.Next->is(TT_DictLiteral))
4559     return true;
4560 
4561   if (Left.is(TT_CtorInitializerColon))
4562     return Style.BreakConstructorInitializers == FormatStyle::BCIS_AfterColon;
4563   if (Right.is(TT_CtorInitializerColon))
4564     return Style.BreakConstructorInitializers != FormatStyle::BCIS_AfterColon;
4565   if (Left.is(TT_CtorInitializerComma) &&
4566       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma)
4567     return false;
4568   if (Right.is(TT_CtorInitializerComma) &&
4569       Style.BreakConstructorInitializers == FormatStyle::BCIS_BeforeComma)
4570     return true;
4571   if (Left.is(TT_InheritanceComma) &&
4572       Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma)
4573     return false;
4574   if (Right.is(TT_InheritanceComma) &&
4575       Style.BreakInheritanceList == FormatStyle::BILS_BeforeComma)
4576     return true;
4577   if (Left.is(TT_ArrayInitializerLSquare))
4578     return true;
4579   if (Right.is(tok::kw_typename) && Left.isNot(tok::kw_const))
4580     return true;
4581   if ((Left.isBinaryOperator() || Left.is(TT_BinaryOperator)) &&
4582       !Left.isOneOf(tok::arrowstar, tok::lessless) &&
4583       Style.BreakBeforeBinaryOperators != FormatStyle::BOS_All &&
4584       (Style.BreakBeforeBinaryOperators == FormatStyle::BOS_None ||
4585        Left.getPrecedence() == prec::Assignment))
4586     return true;
4587   if ((Left.is(TT_AttributeSquare) && Right.is(tok::l_square)) ||
4588       (Left.is(tok::r_square) && Right.is(TT_AttributeSquare)))
4589     return false;
4590 
4591   auto ShortLambdaOption = Style.AllowShortLambdasOnASingleLine;
4592   if (Style.BraceWrapping.BeforeLambdaBody && Right.is(TT_LambdaLBrace)) {
4593     if (isAllmanLambdaBrace(Left))
4594       return !isItAnEmptyLambdaAllowed(Left, ShortLambdaOption);
4595     if (isAllmanLambdaBrace(Right))
4596       return !isItAnEmptyLambdaAllowed(Right, ShortLambdaOption);
4597   }
4598 
4599   return Left.isOneOf(tok::comma, tok::coloncolon, tok::semi, tok::l_brace,
4600                       tok::kw_class, tok::kw_struct, tok::comment) ||
4601          Right.isMemberAccess() ||
4602          Right.isOneOf(TT_TrailingReturnArrow, TT_LambdaArrow, tok::lessless,
4603                        tok::colon, tok::l_square, tok::at) ||
4604          (Left.is(tok::r_paren) &&
4605           Right.isOneOf(tok::identifier, tok::kw_const)) ||
4606          (Left.is(tok::l_paren) && !Right.is(tok::r_paren)) ||
4607          (Left.is(TT_TemplateOpener) && !Right.is(TT_TemplateCloser));
4608 }
4609 
4610 void TokenAnnotator::printDebugInfo(const AnnotatedLine &Line) {
4611   llvm::errs() << "AnnotatedTokens(L=" << Line.Level << "):\n";
4612   const FormatToken *Tok = Line.First;
4613   while (Tok) {
4614     llvm::errs() << " M=" << Tok->MustBreakBefore
4615                  << " C=" << Tok->CanBreakBefore
4616                  << " T=" << getTokenTypeName(Tok->getType())
4617                  << " S=" << Tok->SpacesRequiredBefore
4618                  << " F=" << Tok->Finalized << " B=" << Tok->BlockParameterCount
4619                  << " BK=" << Tok->getBlockKind() << " P=" << Tok->SplitPenalty
4620                  << " Name=" << Tok->Tok.getName() << " L=" << Tok->TotalLength
4621                  << " PPK=" << Tok->getPackingKind() << " FakeLParens=";
4622     for (prec::Level LParen : Tok->FakeLParens)
4623       llvm::errs() << LParen << "/";
4624     llvm::errs() << " FakeRParens=" << Tok->FakeRParens;
4625     llvm::errs() << " II=" << Tok->Tok.getIdentifierInfo();
4626     llvm::errs() << " Text='" << Tok->TokenText << "'\n";
4627     if (!Tok->Next)
4628       assert(Tok == Line.Last);
4629     Tok = Tok->Next;
4630   }
4631   llvm::errs() << "----\n";
4632 }
4633 
4634 FormatStyle::PointerAlignmentStyle
4635 TokenAnnotator::getTokenReferenceAlignment(const FormatToken &Reference) {
4636   assert(Reference.isOneOf(tok::amp, tok::ampamp));
4637   switch (Style.ReferenceAlignment) {
4638   case FormatStyle::RAS_Pointer:
4639     return Style.PointerAlignment;
4640   case FormatStyle::RAS_Left:
4641     return FormatStyle::PAS_Left;
4642   case FormatStyle::RAS_Right:
4643     return FormatStyle::PAS_Right;
4644   case FormatStyle::RAS_Middle:
4645     return FormatStyle::PAS_Middle;
4646   }
4647   assert(0); //"Unhandled value of ReferenceAlignment"
4648   return Style.PointerAlignment;
4649 }
4650 
4651 FormatStyle::PointerAlignmentStyle
4652 TokenAnnotator::getTokenPointerOrReferenceAlignment(
4653     const FormatToken &PointerOrReference) {
4654   if (PointerOrReference.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   }
4666   assert(PointerOrReference.is(tok::star));
4667   return Style.PointerAlignment;
4668 }
4669 
4670 } // namespace format
4671 } // namespace clang
4672