1 //===-- lib/Parser/Fortran-parsers.cpp ------------------------------------===//
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 // Top-level grammar specification for Fortran.  These parsers drive
10 // the tokenization parsers in cooked-tokens.h to consume characters,
11 // recognize the productions of Fortran, and to construct a parse tree.
12 // See ParserCombinators.md for documentation on the parser combinator
13 // library used here to implement an LL recursive descent recognizer.
14 
15 // The productions that follow are derived from the draft Fortran 2018
16 // standard, with some necessary modifications to remove left recursion
17 // and some generalization in order to defer cases where parses depend
18 // on the definitions of symbols.  The "Rxxx" numbers that appear in
19 // comments refer to these numbered requirements in the Fortran standard.
20 
21 // The whole Fortran grammar originally constituted one header file,
22 // but that turned out to require more memory to compile with current
23 // C++ compilers than some people were willing to accept, so now the
24 // various per-type parsers are partitioned into several C++ source
25 // files.  This file contains parsers for constants, types, declarations,
26 // and misfits (mostly clauses 7, 8, & 9 of Fortran 2018).  The others:
27 //  executable-parsers.cpp  Executable statements
28 //  expr-parsers.cpp        Expressions
29 //  io-parsers.cpp          I/O statements and FORMAT
30 //  openmp-parsers.cpp      OpenMP directives
31 //  program-parsers.cpp     Program units
32 
33 #include "basic-parsers.h"
34 #include "expr-parsers.h"
35 #include "misc-parsers.h"
36 #include "stmt-parser.h"
37 #include "token-parsers.h"
38 #include "type-parser-implementation.h"
39 #include "flang/Parser/parse-tree.h"
40 #include "flang/Parser/user-state.h"
41 
42 namespace Fortran::parser {
43 
44 // R601 alphanumeric-character -> letter | digit | underscore
45 // R603 name -> letter [alphanumeric-character]...
46 constexpr auto nonDigitIdChar{letter || otherIdChar};
47 constexpr auto rawName{nonDigitIdChar >> many(nonDigitIdChar || digit)};
48 TYPE_PARSER(space >> sourced(rawName >> construct<Name>()))
49 
50 // R604 constant ->  literal-constant | named-constant
51 // Used only via R607 int-constant and R845 data-stmt-constant.
52 // The look-ahead check prevents occlusion of constant-subobject in
53 // data-stmt-constant.
54 TYPE_PARSER(construct<ConstantValue>(literalConstant) ||
55     construct<ConstantValue>(namedConstant / !"%"_tok / !"("_tok))
56 
57 // R608 intrinsic-operator ->
58 //        power-op | mult-op | add-op | concat-op | rel-op |
59 //        not-op | and-op | or-op | equiv-op
60 // R610 extended-intrinsic-op -> intrinsic-operator
61 // These parsers must be ordered carefully to avoid misrecognition.
62 constexpr auto namedIntrinsicOperator{
63     ".LT." >> pure(DefinedOperator::IntrinsicOperator::LT) ||
64     ".LE." >> pure(DefinedOperator::IntrinsicOperator::LE) ||
65     ".EQ." >> pure(DefinedOperator::IntrinsicOperator::EQ) ||
66     ".NE." >> pure(DefinedOperator::IntrinsicOperator::NE) ||
67     ".GE." >> pure(DefinedOperator::IntrinsicOperator::GE) ||
68     ".GT." >> pure(DefinedOperator::IntrinsicOperator::GT) ||
69     ".NOT." >> pure(DefinedOperator::IntrinsicOperator::NOT) ||
70     ".AND." >> pure(DefinedOperator::IntrinsicOperator::AND) ||
71     ".OR." >> pure(DefinedOperator::IntrinsicOperator::OR) ||
72     ".EQV." >> pure(DefinedOperator::IntrinsicOperator::EQV) ||
73     ".NEQV." >> pure(DefinedOperator::IntrinsicOperator::NEQV) ||
74     extension<LanguageFeature::XOROperator>(
75         ".XOR." >> pure(DefinedOperator::IntrinsicOperator::NEQV)) ||
76     extension<LanguageFeature::LogicalAbbreviations>(
77         ".N." >> pure(DefinedOperator::IntrinsicOperator::NOT) ||
78         ".A." >> pure(DefinedOperator::IntrinsicOperator::AND) ||
79         ".O." >> pure(DefinedOperator::IntrinsicOperator::OR) ||
80         extension<LanguageFeature::XOROperator>(
81             ".X." >> pure(DefinedOperator::IntrinsicOperator::NEQV)))};
82 
83 constexpr auto intrinsicOperator{
84     "**" >> pure(DefinedOperator::IntrinsicOperator::Power) ||
85     "*" >> pure(DefinedOperator::IntrinsicOperator::Multiply) ||
86     "//" >> pure(DefinedOperator::IntrinsicOperator::Concat) ||
87     "/=" >> pure(DefinedOperator::IntrinsicOperator::NE) ||
88     "/" >> pure(DefinedOperator::IntrinsicOperator::Divide) ||
89     "+" >> pure(DefinedOperator::IntrinsicOperator::Add) ||
90     "-" >> pure(DefinedOperator::IntrinsicOperator::Subtract) ||
91     "<=" >> pure(DefinedOperator::IntrinsicOperator::LE) ||
92     extension<LanguageFeature::AlternativeNE>(
93         "<>" >> pure(DefinedOperator::IntrinsicOperator::NE)) ||
94     "<" >> pure(DefinedOperator::IntrinsicOperator::LT) ||
95     "==" >> pure(DefinedOperator::IntrinsicOperator::EQ) ||
96     ">=" >> pure(DefinedOperator::IntrinsicOperator::GE) ||
97     ">" >> pure(DefinedOperator::IntrinsicOperator::GT) ||
98     namedIntrinsicOperator};
99 
100 // R609 defined-operator ->
101 //        defined-unary-op | defined-binary-op | extended-intrinsic-op
102 TYPE_PARSER(construct<DefinedOperator>(intrinsicOperator) ||
103     construct<DefinedOperator>(definedOpName))
104 
105 // R505 implicit-part -> [implicit-part-stmt]... implicit-stmt
106 // TODO: Can overshoot; any trailing PARAMETER, FORMAT, & ENTRY
107 // statements after the last IMPLICIT should be transferred to the
108 // list of declaration-constructs.
109 TYPE_CONTEXT_PARSER("implicit part"_en_US,
110     construct<ImplicitPart>(many(Parser<ImplicitPartStmt>{})))
111 
112 // R506 implicit-part-stmt ->
113 //         implicit-stmt | parameter-stmt | format-stmt | entry-stmt
114 TYPE_PARSER(first(
115     construct<ImplicitPartStmt>(statement(indirect(Parser<ImplicitStmt>{}))),
116     construct<ImplicitPartStmt>(statement(indirect(parameterStmt))),
117     construct<ImplicitPartStmt>(statement(indirect(oldParameterStmt))),
118     construct<ImplicitPartStmt>(statement(indirect(formatStmt))),
119     construct<ImplicitPartStmt>(statement(indirect(entryStmt))),
120     construct<ImplicitPartStmt>(indirect(compilerDirective))))
121 
122 // R512 internal-subprogram -> function-subprogram | subroutine-subprogram
123 // Internal subprograms are not program units, so their END statements
124 // can be followed by ';' and another statement on the same line.
125 TYPE_CONTEXT_PARSER("internal subprogram"_en_US,
126     (construct<InternalSubprogram>(indirect(functionSubprogram)) ||
127         construct<InternalSubprogram>(indirect(subroutineSubprogram))) /
128         forceEndOfStmt)
129 
130 // R511 internal-subprogram-part -> contains-stmt [internal-subprogram]...
131 TYPE_CONTEXT_PARSER("internal subprogram part"_en_US,
132     construct<InternalSubprogramPart>(statement(containsStmt),
133         many(StartNewSubprogram{} >> Parser<InternalSubprogram>{})))
134 
135 // R605 literal-constant ->
136 //        int-literal-constant | real-literal-constant |
137 //        complex-literal-constant | logical-literal-constant |
138 //        char-literal-constant | boz-literal-constant
139 TYPE_PARSER(
140     first(construct<LiteralConstant>(Parser<HollerithLiteralConstant>{}),
141         construct<LiteralConstant>(realLiteralConstant),
142         construct<LiteralConstant>(intLiteralConstant),
143         construct<LiteralConstant>(Parser<ComplexLiteralConstant>{}),
144         construct<LiteralConstant>(Parser<BOZLiteralConstant>{}),
145         construct<LiteralConstant>(charLiteralConstant),
146         construct<LiteralConstant>(Parser<LogicalLiteralConstant>{})))
147 
148 // R606 named-constant -> name
149 TYPE_PARSER(construct<NamedConstant>(name))
150 
151 // R701 type-param-value -> scalar-int-expr | * | :
152 TYPE_PARSER(construct<TypeParamValue>(scalarIntExpr) ||
153     construct<TypeParamValue>(star) ||
154     construct<TypeParamValue>(construct<TypeParamValue::Deferred>(":"_tok)))
155 
156 // R702 type-spec -> intrinsic-type-spec | derived-type-spec
157 // N.B. This type-spec production is one of two instances in the Fortran
158 // grammar where intrinsic types and bare derived type names can clash;
159 // the other is below in R703 declaration-type-spec.  Look-ahead is required
160 // to disambiguate the cases where a derived type name begins with the name
161 // of an intrinsic type, e.g., REALITY.
162 TYPE_CONTEXT_PARSER("type spec"_en_US,
163     construct<TypeSpec>(intrinsicTypeSpec / lookAhead("::"_tok || ")"_tok)) ||
164         construct<TypeSpec>(derivedTypeSpec))
165 
166 // R703 declaration-type-spec ->
167 //        intrinsic-type-spec | TYPE ( intrinsic-type-spec ) |
168 //        TYPE ( derived-type-spec ) | CLASS ( derived-type-spec ) |
169 //        CLASS ( * ) | TYPE ( * )
170 // N.B. It is critical to distribute "parenthesized()" over the alternatives
171 // for TYPE (...), rather than putting the alternatives within it, which
172 // would fail on "TYPE(real_derived)" with a misrecognition of "real" as an
173 // intrinsic-type-spec.
174 TYPE_CONTEXT_PARSER("declaration type spec"_en_US,
175     construct<DeclarationTypeSpec>(intrinsicTypeSpec) ||
176         "TYPE" >>
177             (parenthesized(construct<DeclarationTypeSpec>(intrinsicTypeSpec)) ||
178                 parenthesized(construct<DeclarationTypeSpec>(
179                     construct<DeclarationTypeSpec::Type>(derivedTypeSpec))) ||
180                 construct<DeclarationTypeSpec>(
181                     "( * )" >> construct<DeclarationTypeSpec::TypeStar>())) ||
182         "CLASS" >> parenthesized(construct<DeclarationTypeSpec>(
183                                      construct<DeclarationTypeSpec::Class>(
184                                          derivedTypeSpec)) ||
185                        construct<DeclarationTypeSpec>("*" >>
186                            construct<DeclarationTypeSpec::ClassStar>())) ||
187         extension<LanguageFeature::DECStructures>(
188             construct<DeclarationTypeSpec>(
189                 construct<DeclarationTypeSpec::Record>(
190                     "RECORD /" >> name / "/"))))
191 
192 // R704 intrinsic-type-spec ->
193 //        integer-type-spec | REAL [kind-selector] | DOUBLE PRECISION |
194 //        COMPLEX [kind-selector] | CHARACTER [char-selector] |
195 //        LOGICAL [kind-selector]
196 // Extensions: DOUBLE COMPLEX, BYTE
197 TYPE_CONTEXT_PARSER("intrinsic type spec"_en_US,
198     first(construct<IntrinsicTypeSpec>(integerTypeSpec),
199         construct<IntrinsicTypeSpec>(
200             construct<IntrinsicTypeSpec::Real>("REAL" >> maybe(kindSelector))),
201         construct<IntrinsicTypeSpec>("DOUBLE PRECISION" >>
202             construct<IntrinsicTypeSpec::DoublePrecision>()),
203         construct<IntrinsicTypeSpec>(construct<IntrinsicTypeSpec::Complex>(
204             "COMPLEX" >> maybe(kindSelector))),
205         construct<IntrinsicTypeSpec>(construct<IntrinsicTypeSpec::Character>(
206             "CHARACTER" >> maybe(Parser<CharSelector>{}))),
207         construct<IntrinsicTypeSpec>(construct<IntrinsicTypeSpec::Logical>(
208             "LOGICAL" >> maybe(kindSelector))),
209         construct<IntrinsicTypeSpec>("DOUBLE COMPLEX" >>
210             extension<LanguageFeature::DoubleComplex>(
211                 construct<IntrinsicTypeSpec::DoubleComplex>())),
212         extension<LanguageFeature::Byte>(
213             construct<IntrinsicTypeSpec>(construct<IntegerTypeSpec>(
214                 "BYTE" >> construct<std::optional<KindSelector>>(pure(1)))))))
215 
216 // R705 integer-type-spec -> INTEGER [kind-selector]
217 TYPE_PARSER(construct<IntegerTypeSpec>("INTEGER" >> maybe(kindSelector)))
218 
219 // R706 kind-selector -> ( [KIND =] scalar-int-constant-expr )
220 // Legacy extension: kind-selector -> * digit-string
221 TYPE_PARSER(construct<KindSelector>(
222                 parenthesized(maybe("KIND ="_tok) >> scalarIntConstantExpr)) ||
223     extension<LanguageFeature::StarKind>(construct<KindSelector>(
224         construct<KindSelector::StarSize>("*" >> digitString64 / spaceCheck))))
225 
226 // R707 signed-int-literal-constant -> [sign] int-literal-constant
227 TYPE_PARSER(sourced(construct<SignedIntLiteralConstant>(
228     SignedIntLiteralConstantWithoutKind{}, maybe(underscore >> kindParam))))
229 
230 // R708 int-literal-constant -> digit-string [_ kind-param]
231 // The negated look-ahead for a trailing underscore prevents misrecognition
232 // when the digit string is a numeric kind parameter of a character literal.
233 TYPE_PARSER(construct<IntLiteralConstant>(
234     space >> digitString, maybe(underscore >> kindParam) / !underscore))
235 
236 // R709 kind-param -> digit-string | scalar-int-constant-name
237 TYPE_PARSER(construct<KindParam>(digitString64) ||
238     construct<KindParam>(scalar(integer(constant(name)))))
239 
240 // R712 sign -> + | -
241 // N.B. A sign constitutes a whole token, so a space is allowed in free form
242 // after the sign and before a real-literal-constant or
243 // complex-literal-constant.  A sign is not a unary operator in these contexts.
244 constexpr auto sign{
245     "+"_tok >> pure(Sign::Positive) || "-"_tok >> pure(Sign::Negative)};
246 
247 // R713 signed-real-literal-constant -> [sign] real-literal-constant
248 constexpr auto signedRealLiteralConstant{
249     construct<SignedRealLiteralConstant>(maybe(sign), realLiteralConstant)};
250 
251 // R714 real-literal-constant ->
252 //        significand [exponent-letter exponent] [_ kind-param] |
253 //        digit-string exponent-letter exponent [_ kind-param]
254 // R715 significand -> digit-string . [digit-string] | . digit-string
255 // R716 exponent-letter -> E | D
256 // Extension: Q
257 // R717 exponent -> signed-digit-string
258 constexpr auto exponentPart{
259     ("ed"_ch || extension<LanguageFeature::QuadPrecision>("q"_ch)) >>
260     SignedDigitString{}};
261 
262 TYPE_CONTEXT_PARSER("REAL literal constant"_en_US,
263     space >>
264         construct<RealLiteralConstant>(
265             sourced((digitString >> "."_ch >>
266                             !(some(letter) >>
267                                 "."_ch /* don't misinterpret 1.AND. */) >>
268                             maybe(digitString) >> maybe(exponentPart) >> ok ||
269                         "."_ch >> digitString >> maybe(exponentPart) >> ok ||
270                         digitString >> exponentPart >> ok) >>
271                 construct<RealLiteralConstant::Real>()),
272             maybe(underscore >> kindParam)))
273 
274 // R718 complex-literal-constant -> ( real-part , imag-part )
275 TYPE_CONTEXT_PARSER("COMPLEX literal constant"_en_US,
276     parenthesized(construct<ComplexLiteralConstant>(
277         Parser<ComplexPart>{} / ",", Parser<ComplexPart>{})))
278 
279 // PGI/Intel extension: signed complex literal constant
280 TYPE_PARSER(construct<SignedComplexLiteralConstant>(
281     sign, Parser<ComplexLiteralConstant>{}))
282 
283 // R719 real-part ->
284 //        signed-int-literal-constant | signed-real-literal-constant |
285 //        named-constant
286 // R720 imag-part ->
287 //        signed-int-literal-constant | signed-real-literal-constant |
288 //        named-constant
289 TYPE_PARSER(construct<ComplexPart>(signedRealLiteralConstant) ||
290     construct<ComplexPart>(signedIntLiteralConstant) ||
291     construct<ComplexPart>(namedConstant))
292 
293 // R721 char-selector ->
294 //        length-selector |
295 //        ( LEN = type-param-value , KIND = scalar-int-constant-expr ) |
296 //        ( type-param-value , [KIND =] scalar-int-constant-expr ) |
297 //        ( KIND = scalar-int-constant-expr [, LEN = type-param-value] )
298 TYPE_PARSER(construct<CharSelector>(Parser<LengthSelector>{}) ||
299     parenthesized(construct<CharSelector>(
300         "LEN =" >> typeParamValue, ", KIND =" >> scalarIntConstantExpr)) ||
301     parenthesized(construct<CharSelector>(
302         typeParamValue / ",", maybe("KIND ="_tok) >> scalarIntConstantExpr)) ||
303     parenthesized(construct<CharSelector>(
304         "KIND =" >> scalarIntConstantExpr, maybe(", LEN =" >> typeParamValue))))
305 
306 // R722 length-selector -> ( [LEN =] type-param-value ) | * char-length [,]
307 // N.B. The trailing [,] in the production is permitted by the Standard
308 // only in the context of a type-declaration-stmt, but even with that
309 // limitation, it would seem to be unnecessary and buggy to consume the comma
310 // here.
311 TYPE_PARSER(construct<LengthSelector>(
312                 parenthesized(maybe("LEN ="_tok) >> typeParamValue)) ||
313     construct<LengthSelector>("*" >> charLength /* / maybe(","_tok) */))
314 
315 // R723 char-length -> ( type-param-value ) | digit-string
316 TYPE_PARSER(construct<CharLength>(parenthesized(typeParamValue)) ||
317     construct<CharLength>(space >> digitString64 / spaceCheck))
318 
319 // R724 char-literal-constant ->
320 //        [kind-param _] ' [rep-char]... ' |
321 //        [kind-param _] " [rep-char]... "
322 // "rep-char" is any non-control character.  Doubled interior quotes are
323 // combined.  Backslash escapes can be enabled.
324 // N.B. the parsing of "kind-param" takes care to not consume the '_'.
325 TYPE_CONTEXT_PARSER("CHARACTER literal constant"_en_US,
326     construct<CharLiteralConstant>(
327         kindParam / underscore, charLiteralConstantWithoutKind) ||
328         construct<CharLiteralConstant>(construct<std::optional<KindParam>>(),
329             space >> charLiteralConstantWithoutKind))
330 
331 TYPE_CONTEXT_PARSER(
332     "Hollerith"_en_US, construct<HollerithLiteralConstant>(rawHollerithLiteral))
333 
334 // R725 logical-literal-constant ->
335 //        .TRUE. [_ kind-param] | .FALSE. [_ kind-param]
336 // Also accept .T. and .F. as extensions.
337 TYPE_PARSER(construct<LogicalLiteralConstant>(
338                 logicalTRUE, maybe(underscore >> kindParam)) ||
339     construct<LogicalLiteralConstant>(
340         logicalFALSE, maybe(underscore >> kindParam)))
341 
342 // R726 derived-type-def ->
343 //        derived-type-stmt [type-param-def-stmt]...
344 //        [private-or-sequence]... [component-part]
345 //        [type-bound-procedure-part] end-type-stmt
346 // R735 component-part -> [component-def-stmt]...
347 TYPE_CONTEXT_PARSER("derived type definition"_en_US,
348     construct<DerivedTypeDef>(statement(Parser<DerivedTypeStmt>{}),
349         many(unambiguousStatement(Parser<TypeParamDefStmt>{})),
350         many(statement(Parser<PrivateOrSequence>{})),
351         many(inContext("component"_en_US,
352             unambiguousStatement(Parser<ComponentDefStmt>{}))),
353         maybe(Parser<TypeBoundProcedurePart>{}),
354         statement(Parser<EndTypeStmt>{})))
355 
356 // R727 derived-type-stmt ->
357 //        TYPE [[, type-attr-spec-list] ::] type-name [(
358 //        type-param-name-list )]
359 TYPE_CONTEXT_PARSER("TYPE statement"_en_US,
360     construct<DerivedTypeStmt>(
361         "TYPE" >> optionalListBeforeColons(Parser<TypeAttrSpec>{}), name,
362         defaulted(parenthesized(nonemptyList(name)))))
363 
364 // R728 type-attr-spec ->
365 //        ABSTRACT | access-spec | BIND(C) | EXTENDS ( parent-type-name )
366 TYPE_PARSER(construct<TypeAttrSpec>(construct<Abstract>("ABSTRACT"_tok)) ||
367     construct<TypeAttrSpec>(construct<TypeAttrSpec::BindC>("BIND ( C )"_tok)) ||
368     construct<TypeAttrSpec>(
369         construct<TypeAttrSpec::Extends>("EXTENDS" >> parenthesized(name))) ||
370     construct<TypeAttrSpec>(accessSpec))
371 
372 // R729 private-or-sequence -> private-components-stmt | sequence-stmt
373 TYPE_PARSER(construct<PrivateOrSequence>(Parser<PrivateStmt>{}) ||
374     construct<PrivateOrSequence>(Parser<SequenceStmt>{}))
375 
376 // R730 end-type-stmt -> END TYPE [type-name]
377 TYPE_PARSER(construct<EndTypeStmt>(
378     recovery("END TYPE" >> maybe(name), endStmtErrorRecovery)))
379 
380 // R731 sequence-stmt -> SEQUENCE
381 TYPE_PARSER(construct<SequenceStmt>("SEQUENCE"_tok))
382 
383 // R732 type-param-def-stmt ->
384 //        integer-type-spec , type-param-attr-spec :: type-param-decl-list
385 // R734 type-param-attr-spec -> KIND | LEN
386 constexpr auto kindOrLen{"KIND" >> pure(common::TypeParamAttr::Kind) ||
387     "LEN" >> pure(common::TypeParamAttr::Len)};
388 TYPE_PARSER(construct<TypeParamDefStmt>(integerTypeSpec / ",", kindOrLen,
389     "::" >> nonemptyList("expected type parameter declarations"_err_en_US,
390                 Parser<TypeParamDecl>{})))
391 
392 // R733 type-param-decl -> type-param-name [= scalar-int-constant-expr]
393 TYPE_PARSER(construct<TypeParamDecl>(name, maybe("=" >> scalarIntConstantExpr)))
394 
395 // R736 component-def-stmt -> data-component-def-stmt |
396 //        proc-component-def-stmt
397 // Accidental extension not enabled here: PGI accepts type-param-def-stmt in
398 // component-part of derived-type-def.
399 TYPE_PARSER(recovery(
400     withMessage("expected component definition"_err_en_US,
401         first(construct<ComponentDefStmt>(Parser<DataComponentDefStmt>{}),
402             construct<ComponentDefStmt>(Parser<ProcComponentDefStmt>{}))),
403     construct<ComponentDefStmt>(inStmtErrorRecovery)))
404 
405 // R737 data-component-def-stmt ->
406 //        declaration-type-spec [[, component-attr-spec-list] ::]
407 //        component-decl-list
408 // N.B. The standard requires double colons if there's an initializer.
409 TYPE_PARSER(construct<DataComponentDefStmt>(declarationTypeSpec,
410     optionalListBeforeColons(Parser<ComponentAttrSpec>{}),
411     nonemptyList(
412         "expected component declarations"_err_en_US, Parser<ComponentDecl>{})))
413 
414 // R738 component-attr-spec ->
415 //        access-spec | ALLOCATABLE |
416 //        CODIMENSION lbracket coarray-spec rbracket |
417 //        CONTIGUOUS | DIMENSION ( component-array-spec ) | POINTER
418 TYPE_PARSER(construct<ComponentAttrSpec>(accessSpec) ||
419     construct<ComponentAttrSpec>(allocatable) ||
420     construct<ComponentAttrSpec>("CODIMENSION" >> coarraySpec) ||
421     construct<ComponentAttrSpec>(contiguous) ||
422     construct<ComponentAttrSpec>("DIMENSION" >> Parser<ComponentArraySpec>{}) ||
423     construct<ComponentAttrSpec>(pointer) ||
424     construct<ComponentAttrSpec>(recovery(
425         fail<ErrorRecovery>(
426             "type parameter definitions must appear before component declarations"_err_en_US),
427         kindOrLen >> construct<ErrorRecovery>())))
428 
429 // R739 component-decl ->
430 //        component-name [( component-array-spec )]
431 //        [lbracket coarray-spec rbracket] [* char-length]
432 //        [component-initialization]
433 TYPE_CONTEXT_PARSER("component declaration"_en_US,
434     construct<ComponentDecl>(name, maybe(Parser<ComponentArraySpec>{}),
435         maybe(coarraySpec), maybe("*" >> charLength), maybe(initialization)))
436 
437 // R740 component-array-spec ->
438 //        explicit-shape-spec-list | deferred-shape-spec-list
439 // N.B. Parenthesized here rather than around references to this production.
440 TYPE_PARSER(construct<ComponentArraySpec>(parenthesized(
441                 nonemptyList("expected explicit shape specifications"_err_en_US,
442                     explicitShapeSpec))) ||
443     construct<ComponentArraySpec>(parenthesized(deferredShapeSpecList)))
444 
445 // R741 proc-component-def-stmt ->
446 //        PROCEDURE ( [proc-interface] ) , proc-component-attr-spec-list
447 //          :: proc-decl-list
448 TYPE_CONTEXT_PARSER("PROCEDURE component definition statement"_en_US,
449     construct<ProcComponentDefStmt>(
450         "PROCEDURE" >> parenthesized(maybe(procInterface)),
451         localRecovery("expected PROCEDURE component attributes"_err_en_US,
452             "," >> nonemptyList(Parser<ProcComponentAttrSpec>{}), ok),
453         localRecovery("expected PROCEDURE declarations"_err_en_US,
454             "::" >> nonemptyList(procDecl), SkipTo<'\n'>{})))
455 
456 // R742 proc-component-attr-spec ->
457 //        access-spec | NOPASS | PASS [(arg-name)] | POINTER
458 constexpr auto noPass{construct<NoPass>("NOPASS"_tok)};
459 constexpr auto pass{construct<Pass>("PASS" >> maybe(parenthesized(name)))};
460 TYPE_PARSER(construct<ProcComponentAttrSpec>(accessSpec) ||
461     construct<ProcComponentAttrSpec>(noPass) ||
462     construct<ProcComponentAttrSpec>(pass) ||
463     construct<ProcComponentAttrSpec>(pointer))
464 
465 // R744 initial-data-target -> designator
466 constexpr auto initialDataTarget{indirect(designator)};
467 
468 // R743 component-initialization ->
469 //        = constant-expr | => null-init | => initial-data-target
470 // R805 initialization ->
471 //        = constant-expr | => null-init | => initial-data-target
472 // Universal extension: initialization -> / data-stmt-value-list /
473 TYPE_PARSER(construct<Initialization>("=>" >> nullInit) ||
474     construct<Initialization>("=>" >> initialDataTarget) ||
475     construct<Initialization>("=" >> constantExpr) ||
476     extension<LanguageFeature::SlashInitialization>(construct<Initialization>(
477         "/" >> nonemptyList("expected values"_err_en_US,
478                    indirect(Parser<DataStmtValue>{})) /
479             "/")))
480 
481 // R745 private-components-stmt -> PRIVATE
482 // R747 binding-private-stmt -> PRIVATE
483 TYPE_PARSER(construct<PrivateStmt>("PRIVATE"_tok))
484 
485 // R746 type-bound-procedure-part ->
486 //        contains-stmt [binding-private-stmt] [type-bound-proc-binding]...
487 TYPE_CONTEXT_PARSER("type bound procedure part"_en_US,
488     construct<TypeBoundProcedurePart>(statement(containsStmt),
489         maybe(statement(Parser<PrivateStmt>{})),
490         many(statement(Parser<TypeBoundProcBinding>{}))))
491 
492 // R748 type-bound-proc-binding ->
493 //        type-bound-procedure-stmt | type-bound-generic-stmt |
494 //        final-procedure-stmt
495 TYPE_CONTEXT_PARSER("type bound procedure binding"_en_US,
496     recovery(
497         first(construct<TypeBoundProcBinding>(Parser<TypeBoundProcedureStmt>{}),
498             construct<TypeBoundProcBinding>(Parser<TypeBoundGenericStmt>{}),
499             construct<TypeBoundProcBinding>(Parser<FinalProcedureStmt>{})),
500         construct<TypeBoundProcBinding>(
501             !"END"_tok >> SkipTo<'\n'>{} >> construct<ErrorRecovery>())))
502 
503 // R749 type-bound-procedure-stmt ->
504 //        PROCEDURE [[, bind-attr-list] ::] type-bound-proc-decl-list |
505 //        PROCEDURE ( interface-name ) , bind-attr-list :: binding-name-list
506 TYPE_CONTEXT_PARSER("type bound PROCEDURE statement"_en_US,
507     "PROCEDURE" >>
508         (construct<TypeBoundProcedureStmt>(
509              construct<TypeBoundProcedureStmt::WithInterface>(
510                  parenthesized(name),
511                  localRecovery("expected list of binding attributes"_err_en_US,
512                      "," >> nonemptyList(Parser<BindAttr>{}), ok),
513                  localRecovery("expected list of binding names"_err_en_US,
514                      "::" >> listOfNames, SkipTo<'\n'>{}))) ||
515             construct<TypeBoundProcedureStmt>(
516                 construct<TypeBoundProcedureStmt::WithoutInterface>(
517                     optionalListBeforeColons(Parser<BindAttr>{}),
518                     nonemptyList(
519                         "expected type bound procedure declarations"_err_en_US,
520                         Parser<TypeBoundProcDecl>{})))))
521 
522 // R750 type-bound-proc-decl -> binding-name [=> procedure-name]
523 TYPE_PARSER(construct<TypeBoundProcDecl>(name, maybe("=>" >> name)))
524 
525 // R751 type-bound-generic-stmt ->
526 //        GENERIC [, access-spec] :: generic-spec => binding-name-list
527 TYPE_CONTEXT_PARSER("type bound GENERIC statement"_en_US,
528     construct<TypeBoundGenericStmt>("GENERIC" >> maybe("," >> accessSpec),
529         "::" >> indirect(genericSpec), "=>" >> listOfNames))
530 
531 // R752 bind-attr ->
532 //        access-spec | DEFERRED | NON_OVERRIDABLE | NOPASS | PASS [(arg-name)]
533 TYPE_PARSER(construct<BindAttr>(accessSpec) ||
534     construct<BindAttr>(construct<BindAttr::Deferred>("DEFERRED"_tok)) ||
535     construct<BindAttr>(
536         construct<BindAttr::Non_Overridable>("NON_OVERRIDABLE"_tok)) ||
537     construct<BindAttr>(noPass) || construct<BindAttr>(pass))
538 
539 // R753 final-procedure-stmt -> FINAL [::] final-subroutine-name-list
540 TYPE_CONTEXT_PARSER("FINAL statement"_en_US,
541     construct<FinalProcedureStmt>("FINAL" >> maybe("::"_tok) >> listOfNames))
542 
543 // R754 derived-type-spec -> type-name [(type-param-spec-list)]
544 TYPE_PARSER(construct<DerivedTypeSpec>(name,
545     defaulted(parenthesized(nonemptyList(
546         "expected type parameters"_err_en_US, Parser<TypeParamSpec>{})))))
547 
548 // R755 type-param-spec -> [keyword =] type-param-value
549 TYPE_PARSER(construct<TypeParamSpec>(maybe(keyword / "="), typeParamValue))
550 
551 // R756 structure-constructor -> derived-type-spec ( [component-spec-list] )
552 TYPE_PARSER((construct<StructureConstructor>(derivedTypeSpec,
553                  parenthesized(optionalList(Parser<ComponentSpec>{}))) ||
554                 // This alternative corrects misrecognition of the
555                 // component-spec-list as the type-param-spec-list in
556                 // derived-type-spec.
557                 construct<StructureConstructor>(
558                     construct<DerivedTypeSpec>(
559                         name, construct<std::list<TypeParamSpec>>()),
560                     parenthesized(optionalList(Parser<ComponentSpec>{})))) /
561     !"("_tok)
562 
563 // R757 component-spec -> [keyword =] component-data-source
564 TYPE_PARSER(construct<ComponentSpec>(
565     maybe(keyword / "="), Parser<ComponentDataSource>{}))
566 
567 // R758 component-data-source -> expr | data-target | proc-target
568 TYPE_PARSER(construct<ComponentDataSource>(indirect(expr)))
569 
570 // R759 enum-def ->
571 //        enum-def-stmt enumerator-def-stmt [enumerator-def-stmt]...
572 //        end-enum-stmt
573 TYPE_CONTEXT_PARSER("enum definition"_en_US,
574     construct<EnumDef>(statement(Parser<EnumDefStmt>{}),
575         some(unambiguousStatement(Parser<EnumeratorDefStmt>{})),
576         statement(Parser<EndEnumStmt>{})))
577 
578 // R760 enum-def-stmt -> ENUM, BIND(C)
579 TYPE_PARSER(construct<EnumDefStmt>("ENUM , BIND ( C )"_tok))
580 
581 // R761 enumerator-def-stmt -> ENUMERATOR [::] enumerator-list
582 TYPE_CONTEXT_PARSER("ENUMERATOR statement"_en_US,
583     construct<EnumeratorDefStmt>("ENUMERATOR" >> maybe("::"_tok) >>
584         nonemptyList("expected enumerators"_err_en_US, Parser<Enumerator>{})))
585 
586 // R762 enumerator -> named-constant [= scalar-int-constant-expr]
587 TYPE_PARSER(
588     construct<Enumerator>(namedConstant, maybe("=" >> scalarIntConstantExpr)))
589 
590 // R763 end-enum-stmt -> END ENUM
591 TYPE_PARSER(recovery("END ENUM"_tok, "END" >> SkipPast<'\n'>{}) >>
592     construct<EndEnumStmt>())
593 
594 // R801 type-declaration-stmt ->
595 //        declaration-type-spec [[, attr-spec]... ::] entity-decl-list
596 constexpr auto entityDeclWithoutEqInit{construct<EntityDecl>(name,
597     maybe(arraySpec), maybe(coarraySpec), maybe("*" >> charLength),
598     !"="_tok >> maybe(initialization))}; // old-style REAL A/0/ still works
599 TYPE_PARSER(
600     construct<TypeDeclarationStmt>(declarationTypeSpec,
601         defaulted("," >> nonemptyList(Parser<AttrSpec>{})) / "::",
602         nonemptyList("expected entity declarations"_err_en_US, entityDecl)) ||
603     // C806: no initializers allowed without colons ("REALA=1" is ambiguous)
604     construct<TypeDeclarationStmt>(declarationTypeSpec,
605         construct<std::list<AttrSpec>>(),
606         nonemptyList("expected entity declarations"_err_en_US,
607             entityDeclWithoutEqInit)) ||
608     // PGI-only extension: comma in place of doubled colons
609     extension<LanguageFeature::MissingColons>(construct<TypeDeclarationStmt>(
610         declarationTypeSpec, defaulted("," >> nonemptyList(Parser<AttrSpec>{})),
611         withMessage("expected entity declarations"_err_en_US,
612             "," >> nonemptyList(entityDecl)))))
613 
614 // R802 attr-spec ->
615 //        access-spec | ALLOCATABLE | ASYNCHRONOUS |
616 //        CODIMENSION lbracket coarray-spec rbracket | CONTIGUOUS |
617 //        DIMENSION ( array-spec ) | EXTERNAL | INTENT ( intent-spec ) |
618 //        INTRINSIC | language-binding-spec | OPTIONAL | PARAMETER | POINTER |
619 //        PROTECTED | SAVE | TARGET | VALUE | VOLATILE
620 TYPE_PARSER(construct<AttrSpec>(accessSpec) ||
621     construct<AttrSpec>(allocatable) ||
622     construct<AttrSpec>(construct<Asynchronous>("ASYNCHRONOUS"_tok)) ||
623     construct<AttrSpec>("CODIMENSION" >> coarraySpec) ||
624     construct<AttrSpec>(contiguous) ||
625     construct<AttrSpec>("DIMENSION" >> arraySpec) ||
626     construct<AttrSpec>(construct<External>("EXTERNAL"_tok)) ||
627     construct<AttrSpec>("INTENT" >> parenthesized(intentSpec)) ||
628     construct<AttrSpec>(construct<Intrinsic>("INTRINSIC"_tok)) ||
629     construct<AttrSpec>(languageBindingSpec) || construct<AttrSpec>(optional) ||
630     construct<AttrSpec>(construct<Parameter>("PARAMETER"_tok)) ||
631     construct<AttrSpec>(pointer) || construct<AttrSpec>(protectedAttr) ||
632     construct<AttrSpec>(save) ||
633     construct<AttrSpec>(construct<Target>("TARGET"_tok)) ||
634     construct<AttrSpec>(construct<Value>("VALUE"_tok)) ||
635     construct<AttrSpec>(construct<Volatile>("VOLATILE"_tok)))
636 
637 // R804 object-name -> name
638 constexpr auto objectName{name};
639 
640 // R803 entity-decl ->
641 //        object-name [( array-spec )] [lbracket coarray-spec rbracket]
642 //          [* char-length] [initialization] |
643 //        function-name [* char-length]
644 TYPE_PARSER(construct<EntityDecl>(objectName, maybe(arraySpec),
645     maybe(coarraySpec), maybe("*" >> charLength), maybe(initialization)))
646 
647 // R806 null-init -> function-reference
648 // TODO: confirm in semantics that NULL still intrinsic in this scope
649 TYPE_PARSER(construct<NullInit>("NULL ( )"_tok) / !"("_tok)
650 
651 // R807 access-spec -> PUBLIC | PRIVATE
652 TYPE_PARSER(construct<AccessSpec>("PUBLIC" >> pure(AccessSpec::Kind::Public)) ||
653     construct<AccessSpec>("PRIVATE" >> pure(AccessSpec::Kind::Private)))
654 
655 // R808 language-binding-spec ->
656 //        BIND ( C [, NAME = scalar-default-char-constant-expr] )
657 // R1528 proc-language-binding-spec -> language-binding-spec
658 TYPE_PARSER(construct<LanguageBindingSpec>(
659     "BIND ( C" >> maybe(", NAME =" >> scalarDefaultCharConstantExpr) / ")"))
660 
661 // R809 coarray-spec -> deferred-coshape-spec-list | explicit-coshape-spec
662 // N.B. Bracketed here rather than around references, for consistency with
663 // array-spec.
664 TYPE_PARSER(
665     construct<CoarraySpec>(bracketed(Parser<DeferredCoshapeSpecList>{})) ||
666     construct<CoarraySpec>(bracketed(Parser<ExplicitCoshapeSpec>{})))
667 
668 // R810 deferred-coshape-spec -> :
669 // deferred-coshape-spec-list - just a list of colons
670 inline int listLength(std::list<Success> &&xs) { return xs.size(); }
671 
672 TYPE_PARSER(construct<DeferredCoshapeSpecList>(
673     applyFunction(listLength, nonemptyList(":"_tok))))
674 
675 // R811 explicit-coshape-spec ->
676 //        [[lower-cobound :] upper-cobound ,]... [lower-cobound :] *
677 // R812 lower-cobound -> specification-expr
678 // R813 upper-cobound -> specification-expr
679 TYPE_PARSER(construct<ExplicitCoshapeSpec>(
680     many(explicitShapeSpec / ","), maybe(specificationExpr / ":") / "*"))
681 
682 // R815 array-spec ->
683 //        explicit-shape-spec-list | assumed-shape-spec-list |
684 //        deferred-shape-spec-list | assumed-size-spec | implied-shape-spec |
685 //        implied-shape-or-assumed-size-spec | assumed-rank-spec
686 // N.B. Parenthesized here rather than around references to avoid
687 // a need for forced look-ahead.
688 // Shape specs that could be deferred-shape-spec or assumed-shape-spec
689 // (e.g. '(:,:)') are parsed as the former.
690 TYPE_PARSER(
691     construct<ArraySpec>(parenthesized(nonemptyList(explicitShapeSpec))) ||
692     construct<ArraySpec>(parenthesized(deferredShapeSpecList)) ||
693     construct<ArraySpec>(
694         parenthesized(nonemptyList(Parser<AssumedShapeSpec>{}))) ||
695     construct<ArraySpec>(parenthesized(Parser<AssumedSizeSpec>{})) ||
696     construct<ArraySpec>(parenthesized(Parser<ImpliedShapeSpec>{})) ||
697     construct<ArraySpec>(parenthesized(Parser<AssumedRankSpec>{})))
698 
699 // R816 explicit-shape-spec -> [lower-bound :] upper-bound
700 // R817 lower-bound -> specification-expr
701 // R818 upper-bound -> specification-expr
702 TYPE_PARSER(construct<ExplicitShapeSpec>(
703     maybe(specificationExpr / ":"), specificationExpr))
704 
705 // R819 assumed-shape-spec -> [lower-bound] :
706 TYPE_PARSER(construct<AssumedShapeSpec>(maybe(specificationExpr) / ":"))
707 
708 // R820 deferred-shape-spec -> :
709 // deferred-shape-spec-list - just a list of colons
710 TYPE_PARSER(construct<DeferredShapeSpecList>(
711     applyFunction(listLength, nonemptyList(":"_tok))))
712 
713 // R821 assumed-implied-spec -> [lower-bound :] *
714 TYPE_PARSER(construct<AssumedImpliedSpec>(maybe(specificationExpr / ":") / "*"))
715 
716 // R822 assumed-size-spec -> explicit-shape-spec-list , assumed-implied-spec
717 TYPE_PARSER(construct<AssumedSizeSpec>(
718     nonemptyList(explicitShapeSpec) / ",", assumedImpliedSpec))
719 
720 // R823 implied-shape-or-assumed-size-spec -> assumed-implied-spec
721 // R824 implied-shape-spec -> assumed-implied-spec , assumed-implied-spec-list
722 // I.e., when the assumed-implied-spec-list has a single item, it constitutes an
723 // implied-shape-or-assumed-size-spec; otherwise, an implied-shape-spec.
724 TYPE_PARSER(construct<ImpliedShapeSpec>(nonemptyList(assumedImpliedSpec)))
725 
726 // R825 assumed-rank-spec -> ..
727 TYPE_PARSER(construct<AssumedRankSpec>(".."_tok))
728 
729 // R826 intent-spec -> IN | OUT | INOUT
730 TYPE_PARSER(construct<IntentSpec>("IN OUT" >> pure(IntentSpec::Intent::InOut) ||
731     "IN" >> pure(IntentSpec::Intent::In) ||
732     "OUT" >> pure(IntentSpec::Intent::Out)))
733 
734 // R827 access-stmt -> access-spec [[::] access-id-list]
735 TYPE_PARSER(construct<AccessStmt>(accessSpec,
736     defaulted(maybe("::"_tok) >>
737         nonemptyList("expected names and generic specifications"_err_en_US,
738             Parser<AccessId>{}))))
739 
740 // R828 access-id -> access-name | generic-spec
741 TYPE_PARSER(construct<AccessId>(indirect(genericSpec)) ||
742     construct<AccessId>(name)) // initially ambiguous with genericSpec
743 
744 // R829 allocatable-stmt -> ALLOCATABLE [::] allocatable-decl-list
745 TYPE_PARSER(construct<AllocatableStmt>("ALLOCATABLE" >> maybe("::"_tok) >>
746     nonemptyList(
747         "expected object declarations"_err_en_US, Parser<ObjectDecl>{})))
748 
749 // R830 allocatable-decl ->
750 //        object-name [( array-spec )] [lbracket coarray-spec rbracket]
751 // R860 target-decl ->
752 //        object-name [( array-spec )] [lbracket coarray-spec rbracket]
753 TYPE_PARSER(
754     construct<ObjectDecl>(objectName, maybe(arraySpec), maybe(coarraySpec)))
755 
756 // R831 asynchronous-stmt -> ASYNCHRONOUS [::] object-name-list
757 TYPE_PARSER(construct<AsynchronousStmt>("ASYNCHRONOUS" >> maybe("::"_tok) >>
758     nonemptyList("expected object names"_err_en_US, objectName)))
759 
760 // R832 bind-stmt -> language-binding-spec [::] bind-entity-list
761 TYPE_PARSER(construct<BindStmt>(languageBindingSpec / maybe("::"_tok),
762     nonemptyList("expected bind entities"_err_en_US, Parser<BindEntity>{})))
763 
764 // R833 bind-entity -> entity-name | / common-block-name /
765 TYPE_PARSER(construct<BindEntity>(pure(BindEntity::Kind::Object), name) ||
766     construct<BindEntity>("/" >> pure(BindEntity::Kind::Common), name / "/"))
767 
768 // R834 codimension-stmt -> CODIMENSION [::] codimension-decl-list
769 TYPE_PARSER(construct<CodimensionStmt>("CODIMENSION" >> maybe("::"_tok) >>
770     nonemptyList("expected codimension declarations"_err_en_US,
771         Parser<CodimensionDecl>{})))
772 
773 // R835 codimension-decl -> coarray-name lbracket coarray-spec rbracket
774 TYPE_PARSER(construct<CodimensionDecl>(name, coarraySpec))
775 
776 // R836 contiguous-stmt -> CONTIGUOUS [::] object-name-list
777 TYPE_PARSER(construct<ContiguousStmt>("CONTIGUOUS" >> maybe("::"_tok) >>
778     nonemptyList("expected object names"_err_en_US, objectName)))
779 
780 // R837 data-stmt -> DATA data-stmt-set [[,] data-stmt-set]...
781 TYPE_CONTEXT_PARSER("DATA statement"_en_US,
782     construct<DataStmt>(
783         "DATA" >> nonemptySeparated(Parser<DataStmtSet>{}, maybe(","_tok))))
784 
785 // R838 data-stmt-set -> data-stmt-object-list / data-stmt-value-list /
786 TYPE_PARSER(construct<DataStmtSet>(
787     nonemptyList(
788         "expected DATA statement objects"_err_en_US, Parser<DataStmtObject>{}),
789     withMessage("expected DATA statement value list"_err_en_US,
790         "/"_tok >> nonemptyList("expected DATA statement values"_err_en_US,
791                        Parser<DataStmtValue>{})) /
792         "/"))
793 
794 // R839 data-stmt-object -> variable | data-implied-do
795 TYPE_PARSER(construct<DataStmtObject>(indirect(variable)) ||
796     construct<DataStmtObject>(dataImpliedDo))
797 
798 // R840 data-implied-do ->
799 //        ( data-i-do-object-list , [integer-type-spec ::] data-i-do-variable
800 //        = scalar-int-constant-expr , scalar-int-constant-expr
801 //        [, scalar-int-constant-expr] )
802 // R842 data-i-do-variable -> do-variable
803 TYPE_PARSER(parenthesized(construct<DataImpliedDo>(
804     nonemptyList(Parser<DataIDoObject>{} / lookAhead(","_tok)) / ",",
805     maybe(integerTypeSpec / "::"), loopBounds(scalarIntConstantExpr))))
806 
807 // R841 data-i-do-object ->
808 //        array-element | scalar-structure-component | data-implied-do
809 TYPE_PARSER(construct<DataIDoObject>(scalar(indirect(designator))) ||
810     construct<DataIDoObject>(indirect(dataImpliedDo)))
811 
812 // R843 data-stmt-value -> [data-stmt-repeat *] data-stmt-constant
813 TYPE_PARSER(construct<DataStmtValue>(
814     maybe(Parser<DataStmtRepeat>{} / "*"), Parser<DataStmtConstant>{}))
815 
816 // R847 constant-subobject -> designator
817 // R846 int-constant-subobject -> constant-subobject
818 constexpr auto constantSubobject{constant(indirect(designator))};
819 
820 // R844 data-stmt-repeat -> scalar-int-constant | scalar-int-constant-subobject
821 // R607 int-constant -> constant
822 // Factored into: constant -> literal-constant -> int-literal-constant
823 // The named-constant alternative of constant is subsumed by constant-subobject
824 TYPE_PARSER(construct<DataStmtRepeat>(intLiteralConstant) ||
825     construct<DataStmtRepeat>(scalar(integer(constantSubobject))))
826 
827 // R845 data-stmt-constant ->
828 //        scalar-constant | scalar-constant-subobject |
829 //        signed-int-literal-constant | signed-real-literal-constant |
830 //        null-init | initial-data-target | structure-constructor
831 // TODO: Some structure constructors can be misrecognized as array
832 // references into constant subobjects.
833 TYPE_PARSER(sourced(first(
834     construct<DataStmtConstant>(scalar(Parser<ConstantValue>{})),
835     construct<DataStmtConstant>(nullInit),
836     construct<DataStmtConstant>(scalar(constantSubobject)) / !"("_tok,
837     construct<DataStmtConstant>(Parser<StructureConstructor>{}),
838     construct<DataStmtConstant>(signedRealLiteralConstant),
839     construct<DataStmtConstant>(signedIntLiteralConstant),
840     extension<LanguageFeature::SignedComplexLiteral>(
841         construct<DataStmtConstant>(Parser<SignedComplexLiteralConstant>{})),
842     construct<DataStmtConstant>(initialDataTarget))))
843 
844 // R848 dimension-stmt ->
845 //        DIMENSION [::] array-name ( array-spec )
846 //        [, array-name ( array-spec )]...
847 TYPE_CONTEXT_PARSER("DIMENSION statement"_en_US,
848     construct<DimensionStmt>("DIMENSION" >> maybe("::"_tok) >>
849         nonemptyList("expected array specifications"_err_en_US,
850             construct<DimensionStmt::Declaration>(name, arraySpec))))
851 
852 // R849 intent-stmt -> INTENT ( intent-spec ) [::] dummy-arg-name-list
853 TYPE_CONTEXT_PARSER("INTENT statement"_en_US,
854     construct<IntentStmt>(
855         "INTENT" >> parenthesized(intentSpec) / maybe("::"_tok), listOfNames))
856 
857 // R850 optional-stmt -> OPTIONAL [::] dummy-arg-name-list
858 TYPE_PARSER(
859     construct<OptionalStmt>("OPTIONAL" >> maybe("::"_tok) >> listOfNames))
860 
861 // R851 parameter-stmt -> PARAMETER ( named-constant-def-list )
862 // Legacy extension: omitted parentheses, no implicit typing from names
863 TYPE_CONTEXT_PARSER("PARAMETER statement"_en_US,
864     construct<ParameterStmt>(
865         "PARAMETER" >> parenthesized(nonemptyList(Parser<NamedConstantDef>{}))))
866 TYPE_CONTEXT_PARSER("old style PARAMETER statement"_en_US,
867     extension<LanguageFeature::OldStyleParameter>(construct<OldParameterStmt>(
868         "PARAMETER" >> nonemptyList(Parser<NamedConstantDef>{}))))
869 
870 // R852 named-constant-def -> named-constant = constant-expr
871 TYPE_PARSER(construct<NamedConstantDef>(namedConstant, "=" >> constantExpr))
872 
873 // R853 pointer-stmt -> POINTER [::] pointer-decl-list
874 TYPE_PARSER(construct<PointerStmt>("POINTER" >> maybe("::"_tok) >>
875     nonemptyList(
876         "expected pointer declarations"_err_en_US, Parser<PointerDecl>{})))
877 
878 // R854 pointer-decl ->
879 //        object-name [( deferred-shape-spec-list )] | proc-entity-name
880 TYPE_PARSER(
881     construct<PointerDecl>(name, maybe(parenthesized(deferredShapeSpecList))))
882 
883 // R855 protected-stmt -> PROTECTED [::] entity-name-list
884 TYPE_PARSER(
885     construct<ProtectedStmt>("PROTECTED" >> maybe("::"_tok) >> listOfNames))
886 
887 // R856 save-stmt -> SAVE [[::] saved-entity-list]
888 TYPE_PARSER(construct<SaveStmt>(
889     "SAVE" >> defaulted(maybe("::"_tok) >>
890                   nonemptyList("expected SAVE entities"_err_en_US,
891                       Parser<SavedEntity>{}))))
892 
893 // R857 saved-entity -> object-name | proc-pointer-name | / common-block-name /
894 // R858 proc-pointer-name -> name
895 TYPE_PARSER(construct<SavedEntity>(pure(SavedEntity::Kind::Entity), name) ||
896     construct<SavedEntity>("/" >> pure(SavedEntity::Kind::Common), name / "/"))
897 
898 // R859 target-stmt -> TARGET [::] target-decl-list
899 TYPE_PARSER(construct<TargetStmt>("TARGET" >> maybe("::"_tok) >>
900     nonemptyList("expected objects"_err_en_US, Parser<ObjectDecl>{})))
901 
902 // R861 value-stmt -> VALUE [::] dummy-arg-name-list
903 TYPE_PARSER(construct<ValueStmt>("VALUE" >> maybe("::"_tok) >> listOfNames))
904 
905 // R862 volatile-stmt -> VOLATILE [::] object-name-list
906 TYPE_PARSER(construct<VolatileStmt>("VOLATILE" >> maybe("::"_tok) >>
907     nonemptyList("expected object names"_err_en_US, objectName)))
908 
909 // R866 implicit-name-spec -> EXTERNAL | TYPE
910 constexpr auto implicitNameSpec{
911     "EXTERNAL" >> pure(ImplicitStmt::ImplicitNoneNameSpec::External) ||
912     "TYPE" >> pure(ImplicitStmt::ImplicitNoneNameSpec::Type)};
913 
914 // R863 implicit-stmt ->
915 //        IMPLICIT implicit-spec-list |
916 //        IMPLICIT NONE [( [implicit-name-spec-list] )]
917 TYPE_CONTEXT_PARSER("IMPLICIT statement"_en_US,
918     construct<ImplicitStmt>(
919         "IMPLICIT" >> nonemptyList("expected IMPLICIT specifications"_err_en_US,
920                           Parser<ImplicitSpec>{})) ||
921         construct<ImplicitStmt>("IMPLICIT NONE"_sptok >>
922             defaulted(parenthesized(optionalList(implicitNameSpec)))))
923 
924 // R864 implicit-spec -> declaration-type-spec ( letter-spec-list )
925 // The variant form of declarationTypeSpec is meant to avoid misrecognition
926 // of a letter-spec as a simple parenthesized expression for kind or character
927 // length, e.g., PARAMETER(I=5,N=1); IMPLICIT REAL(I-N)(O-Z) vs.
928 // IMPLICIT REAL(I-N).  The variant form needs to attempt to reparse only
929 // types with optional parenthesized kind/length expressions, so derived
930 // type specs, DOUBLE PRECISION, and DOUBLE COMPLEX need not be considered.
931 constexpr auto noKindSelector{construct<std::optional<KindSelector>>()};
932 constexpr auto implicitSpecDeclarationTypeSpecRetry{
933     construct<DeclarationTypeSpec>(first(
934         construct<IntrinsicTypeSpec>(
935             construct<IntegerTypeSpec>("INTEGER" >> noKindSelector)),
936         construct<IntrinsicTypeSpec>(
937             construct<IntrinsicTypeSpec::Real>("REAL" >> noKindSelector)),
938         construct<IntrinsicTypeSpec>(
939             construct<IntrinsicTypeSpec::Complex>("COMPLEX" >> noKindSelector)),
940         construct<IntrinsicTypeSpec>(construct<IntrinsicTypeSpec::Character>(
941             "CHARACTER" >> construct<std::optional<CharSelector>>())),
942         construct<IntrinsicTypeSpec>(construct<IntrinsicTypeSpec::Logical>(
943             "LOGICAL" >> noKindSelector))))};
944 
945 TYPE_PARSER(construct<ImplicitSpec>(declarationTypeSpec,
946                 parenthesized(nonemptyList(Parser<LetterSpec>{}))) ||
947     construct<ImplicitSpec>(implicitSpecDeclarationTypeSpecRetry,
948         parenthesized(nonemptyList(Parser<LetterSpec>{}))))
949 
950 // R865 letter-spec -> letter [- letter]
951 TYPE_PARSER(space >> (construct<LetterSpec>(letter, maybe("-" >> letter)) ||
952                          construct<LetterSpec>(otherIdChar,
953                              construct<std::optional<const char *>>())))
954 
955 // R867 import-stmt ->
956 //        IMPORT [[::] import-name-list] |
957 //        IMPORT , ONLY : import-name-list | IMPORT , NONE | IMPORT , ALL
958 TYPE_CONTEXT_PARSER("IMPORT statement"_en_US,
959     construct<ImportStmt>(
960         "IMPORT , ONLY :" >> pure(common::ImportKind::Only), listOfNames) ||
961         construct<ImportStmt>(
962             "IMPORT , NONE" >> pure(common::ImportKind::None)) ||
963         construct<ImportStmt>(
964             "IMPORT , ALL" >> pure(common::ImportKind::All)) ||
965         construct<ImportStmt>(
966             "IMPORT" >> maybe("::"_tok) >> optionalList(name)))
967 
968 // R868 namelist-stmt ->
969 //        NAMELIST / namelist-group-name / namelist-group-object-list
970 //        [[,] / namelist-group-name / namelist-group-object-list]...
971 // R869 namelist-group-object -> variable-name
972 TYPE_PARSER(construct<NamelistStmt>("NAMELIST" >>
973     nonemptySeparated(
974         construct<NamelistStmt::Group>("/" >> name / "/", listOfNames),
975         maybe(","_tok))))
976 
977 // R870 equivalence-stmt -> EQUIVALENCE equivalence-set-list
978 // R871 equivalence-set -> ( equivalence-object , equivalence-object-list )
979 TYPE_PARSER(construct<EquivalenceStmt>("EQUIVALENCE" >>
980     nonemptyList(
981         parenthesized(nonemptyList("expected EQUIVALENCE objects"_err_en_US,
982             Parser<EquivalenceObject>{})))))
983 
984 // R872 equivalence-object -> variable-name | array-element | substring
985 TYPE_PARSER(construct<EquivalenceObject>(indirect(designator)))
986 
987 // R873 common-stmt ->
988 //        COMMON [/ [common-block-name] /] common-block-object-list
989 //        [[,] / [common-block-name] / common-block-object-list]...
990 TYPE_PARSER(
991     construct<CommonStmt>("COMMON" >> defaulted("/" >> maybe(name) / "/"),
992         nonemptyList("expected COMMON block objects"_err_en_US,
993             Parser<CommonBlockObject>{}),
994         many(maybe(","_tok) >>
995             construct<CommonStmt::Block>("/" >> maybe(name) / "/",
996                 nonemptyList("expected COMMON block objects"_err_en_US,
997                     Parser<CommonBlockObject>{})))))
998 
999 // R874 common-block-object -> variable-name [( array-spec )]
1000 TYPE_PARSER(construct<CommonBlockObject>(name, maybe(arraySpec)))
1001 
1002 // R901 designator -> object-name | array-element | array-section |
1003 //                    coindexed-named-object | complex-part-designator |
1004 //                    structure-component | substring
1005 // The Standard's productions for designator and its alternatives are
1006 // ambiguous without recourse to a symbol table.  Many of the alternatives
1007 // for designator (viz., array-element, coindexed-named-object,
1008 // and structure-component) are all syntactically just data-ref.
1009 // What designator boils down to is this:
1010 //  It starts with either a name or a character literal.
1011 //  If it starts with a character literal, it must be a substring.
1012 //  If it starts with a name, it's a sequence of %-separated parts;
1013 //  each part is a name, maybe a (section-subscript-list), and
1014 //  maybe an [image-selector].
1015 //  If it's a substring, it ends with (substring-range).
1016 TYPE_CONTEXT_PARSER("designator"_en_US,
1017     sourced(construct<Designator>(substring) || construct<Designator>(dataRef)))
1018 
1019 constexpr auto percentOrDot{"%"_tok ||
1020     // legacy VAX extension for RECORD field access
1021     extension<LanguageFeature::DECStructures>(
1022         "."_tok / lookAhead(OldStructureComponentName{}))};
1023 
1024 // R902 variable -> designator | function-reference
1025 // This production appears to be left-recursive in the grammar via
1026 //   function-reference ->  procedure-designator -> proc-component-ref ->
1027 //     scalar-variable
1028 // and would be so if we were to allow functions to be called via procedure
1029 // pointer components within derived type results of other function references
1030 // (a reasonable extension, esp. in the case of procedure pointer components
1031 // that are NOPASS).  However, Fortran constrains the use of a variable in a
1032 // proc-component-ref to be a data-ref without coindices (C1027).
1033 // Some array element references will be misrecognized as function references.
1034 constexpr auto noMoreAddressing{!"("_tok >> !"["_tok >> !percentOrDot};
1035 TYPE_CONTEXT_PARSER("variable"_en_US,
1036     construct<Variable>(indirect(functionReference / noMoreAddressing)) ||
1037         construct<Variable>(indirect(designator)))
1038 
1039 // R908 substring -> parent-string ( substring-range )
1040 // R909 parent-string ->
1041 //        scalar-variable-name | array-element | coindexed-named-object |
1042 //        scalar-structure-component | scalar-char-literal-constant |
1043 //        scalar-named-constant
1044 TYPE_PARSER(
1045     construct<Substring>(dataRef, parenthesized(Parser<SubstringRange>{})))
1046 
1047 TYPE_PARSER(construct<CharLiteralConstantSubstring>(
1048     charLiteralConstant, parenthesized(Parser<SubstringRange>{})))
1049 
1050 // R910 substring-range -> [scalar-int-expr] : [scalar-int-expr]
1051 TYPE_PARSER(construct<SubstringRange>(
1052     maybe(scalarIntExpr), ":" >> maybe(scalarIntExpr)))
1053 
1054 // R911 data-ref -> part-ref [% part-ref]...
1055 // R914 coindexed-named-object -> data-ref
1056 // R917 array-element -> data-ref
1057 TYPE_PARSER(
1058     construct<DataRef>(nonemptySeparated(Parser<PartRef>{}, percentOrDot)))
1059 
1060 // R912 part-ref -> part-name [( section-subscript-list )] [image-selector]
1061 TYPE_PARSER(construct<PartRef>(name,
1062     defaulted(
1063         parenthesized(nonemptyList(Parser<SectionSubscript>{})) / !"=>"_tok),
1064     maybe(Parser<ImageSelector>{})))
1065 
1066 // R913 structure-component -> data-ref
1067 TYPE_PARSER(construct<StructureComponent>(
1068     construct<DataRef>(some(Parser<PartRef>{} / percentOrDot)), name))
1069 
1070 // R919 subscript -> scalar-int-expr
1071 constexpr auto subscript{scalarIntExpr};
1072 
1073 // R920 section-subscript -> subscript | subscript-triplet | vector-subscript
1074 // R923 vector-subscript -> int-expr
1075 // N.B. The distinction that needs to be made between "subscript" and
1076 // "vector-subscript" is deferred to semantic analysis.
1077 TYPE_PARSER(construct<SectionSubscript>(Parser<SubscriptTriplet>{}) ||
1078     construct<SectionSubscript>(intExpr))
1079 
1080 // R921 subscript-triplet -> [subscript] : [subscript] [: stride]
1081 TYPE_PARSER(construct<SubscriptTriplet>(
1082     maybe(subscript), ":" >> maybe(subscript), maybe(":" >> subscript)))
1083 
1084 // R925 cosubscript -> scalar-int-expr
1085 constexpr auto cosubscript{scalarIntExpr};
1086 
1087 // R924 image-selector ->
1088 //        lbracket cosubscript-list [, image-selector-spec-list] rbracket
1089 TYPE_CONTEXT_PARSER("image selector"_en_US,
1090     construct<ImageSelector>("[" >> nonemptyList(cosubscript / !"="_tok),
1091         defaulted("," >> nonemptyList(Parser<ImageSelectorSpec>{})) / "]"))
1092 
1093 // R926 image-selector-spec ->
1094 //        STAT = stat-variable | TEAM = team-value |
1095 //        TEAM_NUMBER = scalar-int-expr
1096 TYPE_PARSER(construct<ImageSelectorSpec>(construct<ImageSelectorSpec::Stat>(
1097                 "STAT =" >> scalar(integer(indirect(variable))))) ||
1098     construct<ImageSelectorSpec>(construct<TeamValue>("TEAM =" >> teamValue)) ||
1099     construct<ImageSelectorSpec>(construct<ImageSelectorSpec::Team_Number>(
1100         "TEAM_NUMBER =" >> scalarIntExpr)))
1101 
1102 // R927 allocate-stmt ->
1103 //        ALLOCATE ( [type-spec ::] allocation-list [, alloc-opt-list] )
1104 TYPE_CONTEXT_PARSER("ALLOCATE statement"_en_US,
1105     construct<AllocateStmt>("ALLOCATE (" >> maybe(typeSpec / "::"),
1106         nonemptyList(Parser<Allocation>{}),
1107         defaulted("," >> nonemptyList(Parser<AllocOpt>{})) / ")"))
1108 
1109 // R928 alloc-opt ->
1110 //        ERRMSG = errmsg-variable | MOLD = source-expr |
1111 //        SOURCE = source-expr | STAT = stat-variable
1112 // R931 source-expr -> expr
1113 TYPE_PARSER(construct<AllocOpt>(
1114                 construct<AllocOpt::Mold>("MOLD =" >> indirect(expr))) ||
1115     construct<AllocOpt>(
1116         construct<AllocOpt::Source>("SOURCE =" >> indirect(expr))) ||
1117     construct<AllocOpt>(statOrErrmsg))
1118 
1119 // R929 stat-variable -> scalar-int-variable
1120 TYPE_PARSER(construct<StatVariable>(scalar(integer(variable))))
1121 
1122 // R932 allocation ->
1123 //        allocate-object [( allocate-shape-spec-list )]
1124 //        [lbracket allocate-coarray-spec rbracket]
1125 // TODO: allocate-shape-spec-list might be misrecognized as
1126 // the final list of subscripts in allocate-object.
1127 TYPE_PARSER(construct<Allocation>(Parser<AllocateObject>{},
1128     defaulted(parenthesized(nonemptyList(Parser<AllocateShapeSpec>{}))),
1129     maybe(bracketed(Parser<AllocateCoarraySpec>{}))))
1130 
1131 // R933 allocate-object -> variable-name | structure-component
1132 TYPE_PARSER(construct<AllocateObject>(structureComponent) ||
1133     construct<AllocateObject>(name / !"="_tok))
1134 
1135 // R934 allocate-shape-spec -> [lower-bound-expr :] upper-bound-expr
1136 // R938 allocate-coshape-spec -> [lower-bound-expr :] upper-bound-expr
1137 TYPE_PARSER(construct<AllocateShapeSpec>(maybe(boundExpr / ":"), boundExpr))
1138 
1139 // R937 allocate-coarray-spec ->
1140 //      [allocate-coshape-spec-list ,] [lower-bound-expr :] *
1141 TYPE_PARSER(construct<AllocateCoarraySpec>(
1142     defaulted(nonemptyList(Parser<AllocateShapeSpec>{}) / ","),
1143     maybe(boundExpr / ":") / "*"))
1144 
1145 // R939 nullify-stmt -> NULLIFY ( pointer-object-list )
1146 TYPE_CONTEXT_PARSER("NULLIFY statement"_en_US,
1147     "NULLIFY" >> parenthesized(construct<NullifyStmt>(
1148                      nonemptyList(Parser<PointerObject>{}))))
1149 
1150 // R940 pointer-object ->
1151 //        variable-name | structure-component | proc-pointer-name
1152 TYPE_PARSER(construct<PointerObject>(structureComponent) ||
1153     construct<PointerObject>(name))
1154 
1155 // R941 deallocate-stmt ->
1156 //        DEALLOCATE ( allocate-object-list [, dealloc-opt-list] )
1157 TYPE_CONTEXT_PARSER("DEALLOCATE statement"_en_US,
1158     construct<DeallocateStmt>(
1159         "DEALLOCATE (" >> nonemptyList(Parser<AllocateObject>{}),
1160         defaulted("," >> nonemptyList(statOrErrmsg)) / ")"))
1161 
1162 // R942 dealloc-opt -> STAT = stat-variable | ERRMSG = errmsg-variable
1163 // R1165 sync-stat -> STAT = stat-variable | ERRMSG = errmsg-variable
1164 TYPE_PARSER(construct<StatOrErrmsg>("STAT =" >> statVariable) ||
1165     construct<StatOrErrmsg>("ERRMSG =" >> msgVariable))
1166 
1167 // Directives, extensions, and deprecated statements
1168 // !DIR$ IGNORE_TKR [ [(tkr...)] name ]...
1169 // !DIR$ name...
1170 constexpr auto beginDirective{skipStuffBeforeStatement >> "!"_ch};
1171 constexpr auto endDirective{space >> endOfLine};
1172 constexpr auto ignore_tkr{
1173     "DIR$ IGNORE_TKR" >> optionalList(construct<CompilerDirective::IgnoreTKR>(
1174                              defaulted(parenthesized(some("tkr"_ch))), name))};
1175 TYPE_PARSER(
1176     beginDirective >> sourced(construct<CompilerDirective>(ignore_tkr) ||
1177                           construct<CompilerDirective>("DIR$" >>
1178                               many(construct<CompilerDirective::NameValue>(
1179                                   name, maybe("=" >> digitString64))))) /
1180         endDirective)
1181 
1182 TYPE_PARSER(extension<LanguageFeature::CrayPointer>(construct<BasedPointerStmt>(
1183     "POINTER" >> nonemptyList("expected POINTER associations"_err_en_US,
1184                      construct<BasedPointer>("(" >> objectName / ",",
1185                          objectName, maybe(Parser<ArraySpec>{}) / ")")))))
1186 
1187 TYPE_PARSER(construct<StructureStmt>("STRUCTURE /" >> name / "/", pure(true),
1188                 optionalList(entityDecl)) ||
1189     construct<StructureStmt>(
1190         "STRUCTURE" >> name, pure(false), pure<std::list<EntityDecl>>()))
1191 
1192 TYPE_PARSER(construct<StructureField>(statement(StructureComponents{})) ||
1193     construct<StructureField>(indirect(Parser<Union>{})) ||
1194     construct<StructureField>(indirect(Parser<StructureDef>{})))
1195 
1196 TYPE_CONTEXT_PARSER("STRUCTURE definition"_en_US,
1197     extension<LanguageFeature::DECStructures>(construct<StructureDef>(
1198         statement(Parser<StructureStmt>{}), many(Parser<StructureField>{}),
1199         statement(
1200             construct<StructureDef::EndStructureStmt>("END STRUCTURE"_tok)))))
1201 
1202 TYPE_CONTEXT_PARSER("UNION definition"_en_US,
1203     construct<Union>(statement(construct<Union::UnionStmt>("UNION"_tok)),
1204         many(Parser<Map>{}),
1205         statement(construct<Union::EndUnionStmt>("END UNION"_tok))))
1206 
1207 TYPE_CONTEXT_PARSER("MAP definition"_en_US,
1208     construct<Map>(statement(construct<Map::MapStmt>("MAP"_tok)),
1209         many(Parser<StructureField>{}),
1210         statement(construct<Map::EndMapStmt>("END MAP"_tok))))
1211 
1212 TYPE_CONTEXT_PARSER("arithmetic IF statement"_en_US,
1213     deprecated<LanguageFeature::ArithmeticIF>(construct<ArithmeticIfStmt>(
1214         "IF" >> parenthesized(expr), label / ",", label / ",", label)))
1215 
1216 TYPE_CONTEXT_PARSER("ASSIGN statement"_en_US,
1217     deprecated<LanguageFeature::Assign>(
1218         construct<AssignStmt>("ASSIGN" >> label, "TO" >> name)))
1219 
1220 TYPE_CONTEXT_PARSER("assigned GOTO statement"_en_US,
1221     deprecated<LanguageFeature::AssignedGOTO>(construct<AssignedGotoStmt>(
1222         "GO TO" >> name,
1223         defaulted(maybe(","_tok) >>
1224             parenthesized(nonemptyList("expected labels"_err_en_US, label))))))
1225 
1226 TYPE_CONTEXT_PARSER("PAUSE statement"_en_US,
1227     deprecated<LanguageFeature::Pause>(
1228         construct<PauseStmt>("PAUSE" >> maybe(Parser<StopCode>{}))))
1229 
1230 // These requirement productions are defined by the Fortran standard but never
1231 // used directly by the grammar:
1232 //   R620 delimiter -> ( | ) | / | [ | ] | (/ | /)
1233 //   R1027 numeric-expr -> expr
1234 //   R1031 int-constant-expr -> int-expr
1235 //   R1221 dtv-type-spec -> TYPE ( derived-type-spec ) |
1236 //           CLASS ( derived-type-spec )
1237 //
1238 // These requirement productions are defined and used, but need not be
1239 // defined independently here in this file:
1240 //   R771 lbracket -> [
1241 //   R772 rbracket -> ]
1242 //
1243 // Further note that:
1244 //   R607 int-constant -> constant
1245 //     is used only once via R844 scalar-int-constant
1246 //   R904 logical-variable -> variable
1247 //     is used only via scalar-logical-variable
1248 //   R906 default-char-variable -> variable
1249 //     is used only via scalar-default-char-variable
1250 //   R907 int-variable -> variable
1251 //     is used only via scalar-int-variable
1252 //   R915 complex-part-designator -> designator % RE | designator % IM
1253 //     %RE and %IM are initially recognized as structure components
1254 //   R916 type-param-inquiry -> designator % type-param-name
1255 //     is occulted by structure component designators
1256 //   R918 array-section ->
1257 //        data-ref [( substring-range )] | complex-part-designator
1258 //     is not used because parsing is not sensitive to rank
1259 //   R1030 default-char-constant-expr -> default-char-expr
1260 //     is only used via scalar-default-char-constant-expr
1261 } // namespace Fortran::parser
1262