xref: /llvm-project/flang/lib/Semantics/resolve-names-utils.cpp (revision 9e855a6cb84a7c1f9f027474e9b881206df925e3) 
1 //===-- lib/Semantics/resolve-names-utils.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 #include "resolve-names-utils.h"
10 #include "flang/Common/Fortran-features.h"
11 #include "flang/Common/Fortran.h"
12 #include "flang/Common/idioms.h"
13 #include "flang/Common/indirection.h"
14 #include "flang/Evaluate/fold.h"
15 #include "flang/Evaluate/tools.h"
16 #include "flang/Evaluate/traverse.h"
17 #include "flang/Evaluate/type.h"
18 #include "flang/Parser/char-block.h"
19 #include "flang/Parser/parse-tree.h"
20 #include "flang/Semantics/expression.h"
21 #include "flang/Semantics/semantics.h"
22 #include "flang/Semantics/tools.h"
23 #include <initializer_list>
24 #include <variant>
25 
26 namespace Fortran::semantics {
27 
28 using common::LanguageFeature;
29 using common::LogicalOperator;
30 using common::NumericOperator;
31 using common::RelationalOperator;
32 using IntrinsicOperator = parser::DefinedOperator::IntrinsicOperator;
33 
34 static constexpr const char *operatorPrefix{"operator("};
35 
36 static GenericKind MapIntrinsicOperator(IntrinsicOperator);
37 
38 Symbol *Resolve(const parser::Name &name, Symbol *symbol) {
39   if (symbol && !name.symbol) {
40     name.symbol = symbol;
41   }
42   return symbol;
43 }
44 Symbol &Resolve(const parser::Name &name, Symbol &symbol) {
45   return *Resolve(name, &symbol);
46 }
47 
48 parser::MessageFixedText WithSeverity(
49     const parser::MessageFixedText &msg, parser::Severity severity) {
50   return parser::MessageFixedText{
51       msg.text().begin(), msg.text().size(), severity};
52 }
53 
54 bool IsIntrinsicOperator(
55     const SemanticsContext &context, const SourceName &name) {
56   std::string str{name.ToString()};
57   for (int i{0}; i != common::LogicalOperator_enumSize; ++i) {
58     auto names{context.languageFeatures().GetNames(LogicalOperator{i})};
59     if (llvm::is_contained(names, str)) {
60       return true;
61     }
62   }
63   for (int i{0}; i != common::RelationalOperator_enumSize; ++i) {
64     auto names{context.languageFeatures().GetNames(RelationalOperator{i})};
65     if (llvm::is_contained(names, str)) {
66       return true;
67     }
68   }
69   return false;
70 }
71 
72 template <typename E>
73 std::forward_list<std::string> GetOperatorNames(
74     const SemanticsContext &context, E opr) {
75   std::forward_list<std::string> result;
76   for (const char *name : context.languageFeatures().GetNames(opr)) {
77     result.emplace_front(std::string{operatorPrefix} + name + ')');
78   }
79   return result;
80 }
81 
82 std::forward_list<std::string> GetAllNames(
83     const SemanticsContext &context, const SourceName &name) {
84   std::string str{name.ToString()};
85   if (!name.empty() && name.end()[-1] == ')' &&
86       name.ToString().rfind(std::string{operatorPrefix}, 0) == 0) {
87     for (int i{0}; i != common::LogicalOperator_enumSize; ++i) {
88       auto names{GetOperatorNames(context, LogicalOperator{i})};
89       if (llvm::is_contained(names, str)) {
90         return names;
91       }
92     }
93     for (int i{0}; i != common::RelationalOperator_enumSize; ++i) {
94       auto names{GetOperatorNames(context, RelationalOperator{i})};
95       if (llvm::is_contained(names, str)) {
96         return names;
97       }
98     }
99   }
100   return {str};
101 }
102 
103 bool IsLogicalConstant(
104     const SemanticsContext &context, const SourceName &name) {
105   std::string str{name.ToString()};
106   return str == ".true." || str == ".false." ||
107       (context.IsEnabled(LanguageFeature::LogicalAbbreviations) &&
108           (str == ".t" || str == ".f."));
109 }
110 
111 void GenericSpecInfo::Resolve(Symbol *symbol) const {
112   if (symbol) {
113     if (auto *details{symbol->detailsIf<GenericDetails>()}) {
114       details->set_kind(kind_);
115     }
116     if (parseName_) {
117       semantics::Resolve(*parseName_, symbol);
118     }
119   }
120 }
121 
122 void GenericSpecInfo::Analyze(const parser::DefinedOpName &name) {
123   kind_ = GenericKind::OtherKind::DefinedOp;
124   parseName_ = &name.v;
125   symbolName_ = name.v.source;
126 }
127 
128 void GenericSpecInfo::Analyze(const parser::GenericSpec &x) {
129   symbolName_ = x.source;
130   kind_ = common::visit(
131       common::visitors{
132           [&](const parser::Name &y) -> GenericKind {
133             parseName_ = &y;
134             symbolName_ = y.source;
135             return GenericKind::OtherKind::Name;
136           },
137           [&](const parser::DefinedOperator &y) {
138             return common::visit(
139                 common::visitors{
140                     [&](const parser::DefinedOpName &z) -> GenericKind {
141                       Analyze(z);
142                       return GenericKind::OtherKind::DefinedOp;
143                     },
144                     [&](const IntrinsicOperator &z) {
145                       return MapIntrinsicOperator(z);
146                     },
147                 },
148                 y.u);
149           },
150           [&](const parser::GenericSpec::Assignment &) -> GenericKind {
151             return GenericKind::OtherKind::Assignment;
152           },
153           [&](const parser::GenericSpec::ReadFormatted &) -> GenericKind {
154             return GenericKind::DefinedIo::ReadFormatted;
155           },
156           [&](const parser::GenericSpec::ReadUnformatted &) -> GenericKind {
157             return GenericKind::DefinedIo::ReadUnformatted;
158           },
159           [&](const parser::GenericSpec::WriteFormatted &) -> GenericKind {
160             return GenericKind::DefinedIo::WriteFormatted;
161           },
162           [&](const parser::GenericSpec::WriteUnformatted &) -> GenericKind {
163             return GenericKind::DefinedIo::WriteUnformatted;
164           },
165       },
166       x.u);
167 }
168 
169 llvm::raw_ostream &operator<<(
170     llvm::raw_ostream &os, const GenericSpecInfo &info) {
171   os << "GenericSpecInfo: kind=" << info.kind_.ToString();
172   os << " parseName="
173      << (info.parseName_ ? info.parseName_->ToString() : "null");
174   os << " symbolName="
175      << (info.symbolName_ ? info.symbolName_->ToString() : "null");
176   return os;
177 }
178 
179 // parser::DefinedOperator::IntrinsicOperator -> GenericKind
180 static GenericKind MapIntrinsicOperator(IntrinsicOperator op) {
181   switch (op) {
182     SWITCH_COVERS_ALL_CASES
183   case IntrinsicOperator::Concat:
184     return GenericKind::OtherKind::Concat;
185   case IntrinsicOperator::Power:
186     return NumericOperator::Power;
187   case IntrinsicOperator::Multiply:
188     return NumericOperator::Multiply;
189   case IntrinsicOperator::Divide:
190     return NumericOperator::Divide;
191   case IntrinsicOperator::Add:
192     return NumericOperator::Add;
193   case IntrinsicOperator::Subtract:
194     return NumericOperator::Subtract;
195   case IntrinsicOperator::AND:
196     return LogicalOperator::And;
197   case IntrinsicOperator::OR:
198     return LogicalOperator::Or;
199   case IntrinsicOperator::EQV:
200     return LogicalOperator::Eqv;
201   case IntrinsicOperator::NEQV:
202     return LogicalOperator::Neqv;
203   case IntrinsicOperator::NOT:
204     return LogicalOperator::Not;
205   case IntrinsicOperator::LT:
206     return RelationalOperator::LT;
207   case IntrinsicOperator::LE:
208     return RelationalOperator::LE;
209   case IntrinsicOperator::EQ:
210     return RelationalOperator::EQ;
211   case IntrinsicOperator::NE:
212     return RelationalOperator::NE;
213   case IntrinsicOperator::GE:
214     return RelationalOperator::GE;
215   case IntrinsicOperator::GT:
216     return RelationalOperator::GT;
217   }
218 }
219 
220 class ArraySpecAnalyzer {
221 public:
222   ArraySpecAnalyzer(SemanticsContext &context) : context_{context} {}
223   ArraySpec Analyze(const parser::ArraySpec &);
224   ArraySpec AnalyzeDeferredShapeSpecList(const parser::DeferredShapeSpecList &);
225   ArraySpec Analyze(const parser::ComponentArraySpec &);
226   ArraySpec Analyze(const parser::CoarraySpec &);
227 
228 private:
229   SemanticsContext &context_;
230   ArraySpec arraySpec_;
231 
232   template <typename T> void Analyze(const std::list<T> &list) {
233     for (const auto &elem : list) {
234       Analyze(elem);
235     }
236   }
237   void Analyze(const parser::AssumedShapeSpec &);
238   void Analyze(const parser::ExplicitShapeSpec &);
239   void Analyze(const parser::AssumedImpliedSpec &);
240   void Analyze(const parser::DeferredShapeSpecList &);
241   void Analyze(const parser::AssumedRankSpec &);
242   void MakeExplicit(const std::optional<parser::SpecificationExpr> &,
243       const parser::SpecificationExpr &);
244   void MakeImplied(const std::optional<parser::SpecificationExpr> &);
245   void MakeDeferred(int);
246   Bound GetBound(const std::optional<parser::SpecificationExpr> &);
247   Bound GetBound(const parser::SpecificationExpr &);
248 };
249 
250 ArraySpec AnalyzeArraySpec(
251     SemanticsContext &context, const parser::ArraySpec &arraySpec) {
252   return ArraySpecAnalyzer{context}.Analyze(arraySpec);
253 }
254 ArraySpec AnalyzeArraySpec(
255     SemanticsContext &context, const parser::ComponentArraySpec &arraySpec) {
256   return ArraySpecAnalyzer{context}.Analyze(arraySpec);
257 }
258 ArraySpec AnalyzeDeferredShapeSpecList(SemanticsContext &context,
259     const parser::DeferredShapeSpecList &deferredShapeSpecs) {
260   return ArraySpecAnalyzer{context}.AnalyzeDeferredShapeSpecList(
261       deferredShapeSpecs);
262 }
263 ArraySpec AnalyzeCoarraySpec(
264     SemanticsContext &context, const parser::CoarraySpec &coarraySpec) {
265   return ArraySpecAnalyzer{context}.Analyze(coarraySpec);
266 }
267 
268 ArraySpec ArraySpecAnalyzer::Analyze(const parser::ComponentArraySpec &x) {
269   common::visit([this](const auto &y) { Analyze(y); }, x.u);
270   CHECK(!arraySpec_.empty());
271   return arraySpec_;
272 }
273 ArraySpec ArraySpecAnalyzer::Analyze(const parser::ArraySpec &x) {
274   common::visit(common::visitors{
275                     [&](const parser::AssumedSizeSpec &y) {
276                       Analyze(
277                           std::get<std::list<parser::ExplicitShapeSpec>>(y.t));
278                       Analyze(std::get<parser::AssumedImpliedSpec>(y.t));
279                     },
280                     [&](const parser::ImpliedShapeSpec &y) { Analyze(y.v); },
281                     [&](const auto &y) { Analyze(y); },
282                 },
283       x.u);
284   CHECK(!arraySpec_.empty());
285   return arraySpec_;
286 }
287 ArraySpec ArraySpecAnalyzer::AnalyzeDeferredShapeSpecList(
288     const parser::DeferredShapeSpecList &x) {
289   Analyze(x);
290   CHECK(!arraySpec_.empty());
291   return arraySpec_;
292 }
293 ArraySpec ArraySpecAnalyzer::Analyze(const parser::CoarraySpec &x) {
294   common::visit(
295       common::visitors{
296           [&](const parser::DeferredCoshapeSpecList &y) { MakeDeferred(y.v); },
297           [&](const parser::ExplicitCoshapeSpec &y) {
298             Analyze(std::get<std::list<parser::ExplicitShapeSpec>>(y.t));
299             MakeImplied(
300                 std::get<std::optional<parser::SpecificationExpr>>(y.t));
301           },
302       },
303       x.u);
304   CHECK(!arraySpec_.empty());
305   return arraySpec_;
306 }
307 
308 void ArraySpecAnalyzer::Analyze(const parser::AssumedShapeSpec &x) {
309   arraySpec_.push_back(ShapeSpec::MakeAssumedShape(GetBound(x.v)));
310 }
311 void ArraySpecAnalyzer::Analyze(const parser::ExplicitShapeSpec &x) {
312   MakeExplicit(std::get<std::optional<parser::SpecificationExpr>>(x.t),
313       std::get<parser::SpecificationExpr>(x.t));
314 }
315 void ArraySpecAnalyzer::Analyze(const parser::AssumedImpliedSpec &x) {
316   MakeImplied(x.v);
317 }
318 void ArraySpecAnalyzer::Analyze(const parser::DeferredShapeSpecList &x) {
319   MakeDeferred(x.v);
320 }
321 void ArraySpecAnalyzer::Analyze(const parser::AssumedRankSpec &) {
322   arraySpec_.push_back(ShapeSpec::MakeAssumedRank());
323 }
324 
325 void ArraySpecAnalyzer::MakeExplicit(
326     const std::optional<parser::SpecificationExpr> &lb,
327     const parser::SpecificationExpr &ub) {
328   arraySpec_.push_back(ShapeSpec::MakeExplicit(GetBound(lb), GetBound(ub)));
329 }
330 void ArraySpecAnalyzer::MakeImplied(
331     const std::optional<parser::SpecificationExpr> &lb) {
332   arraySpec_.push_back(ShapeSpec::MakeImplied(GetBound(lb)));
333 }
334 void ArraySpecAnalyzer::MakeDeferred(int n) {
335   for (int i = 0; i < n; ++i) {
336     arraySpec_.push_back(ShapeSpec::MakeDeferred());
337   }
338 }
339 
340 Bound ArraySpecAnalyzer::GetBound(
341     const std::optional<parser::SpecificationExpr> &x) {
342   return x ? GetBound(*x) : Bound{1};
343 }
344 Bound ArraySpecAnalyzer::GetBound(const parser::SpecificationExpr &x) {
345   MaybeSubscriptIntExpr expr;
346   if (MaybeExpr maybeExpr{AnalyzeExpr(context_, x.v)}) {
347     if (auto *intExpr{evaluate::UnwrapExpr<SomeIntExpr>(*maybeExpr)}) {
348       expr = evaluate::Fold(context_.foldingContext(),
349           evaluate::ConvertToType<evaluate::SubscriptInteger>(
350               std::move(*intExpr)));
351     }
352   }
353   return Bound{std::move(expr)};
354 }
355 
356 // If SAVE is set on src, set it on all members of dst
357 static void PropagateSaveAttr(
358     const EquivalenceObject &src, EquivalenceSet &dst) {
359   if (src.symbol.attrs().test(Attr::SAVE)) {
360     for (auto &obj : dst) {
361       obj.symbol.attrs().set(Attr::SAVE);
362     }
363   }
364 }
365 static void PropagateSaveAttr(const EquivalenceSet &src, EquivalenceSet &dst) {
366   if (!src.empty()) {
367     PropagateSaveAttr(src.front(), dst);
368   }
369 }
370 
371 void EquivalenceSets::AddToSet(const parser::Designator &designator) {
372   if (CheckDesignator(designator)) {
373     Symbol &symbol{*currObject_.symbol};
374     if (!currSet_.empty()) {
375       // check this symbol against first of set for compatibility
376       Symbol &first{currSet_.front().symbol};
377       CheckCanEquivalence(designator.source, first, symbol) &&
378           CheckCanEquivalence(designator.source, symbol, first);
379     }
380     auto subscripts{currObject_.subscripts};
381     if (subscripts.empty() && symbol.IsObjectArray()) {
382       // record a whole array as its first element
383       for (const ShapeSpec &spec : symbol.get<ObjectEntityDetails>().shape()) {
384         auto &lbound{spec.lbound().GetExplicit().value()};
385         subscripts.push_back(evaluate::ToInt64(lbound).value());
386       }
387     }
388     auto substringStart{currObject_.substringStart};
389     currSet_.emplace_back(
390         symbol, subscripts, substringStart, designator.source);
391     PropagateSaveAttr(currSet_.back(), currSet_);
392   }
393   currObject_ = {};
394 }
395 
396 void EquivalenceSets::FinishSet(const parser::CharBlock &source) {
397   std::set<std::size_t> existing; // indices of sets intersecting this one
398   for (auto &obj : currSet_) {
399     auto it{objectToSet_.find(obj)};
400     if (it != objectToSet_.end()) {
401       existing.insert(it->second); // symbol already in this set
402     }
403   }
404   if (existing.empty()) {
405     sets_.push_back({}); // create a new equivalence set
406     MergeInto(source, currSet_, sets_.size() - 1);
407   } else {
408     auto it{existing.begin()};
409     std::size_t dstIndex{*it};
410     MergeInto(source, currSet_, dstIndex);
411     while (++it != existing.end()) {
412       MergeInto(source, sets_[*it], dstIndex);
413     }
414   }
415   currSet_.clear();
416 }
417 
418 // Report an error or warning if sym1 and sym2 cannot be in the same equivalence
419 // set.
420 bool EquivalenceSets::CheckCanEquivalence(
421     const parser::CharBlock &source, const Symbol &sym1, const Symbol &sym2) {
422   std::optional<parser::MessageFixedText> msg;
423   const DeclTypeSpec *type1{sym1.GetType()};
424   const DeclTypeSpec *type2{sym2.GetType()};
425   bool isDefaultNum1{IsDefaultNumericSequenceType(type1)};
426   bool isAnyNum1{IsAnyNumericSequenceType(type1)};
427   bool isDefaultNum2{IsDefaultNumericSequenceType(type2)};
428   bool isAnyNum2{IsAnyNumericSequenceType(type2)};
429   bool isChar1{IsCharacterSequenceType(type1)};
430   bool isChar2{IsCharacterSequenceType(type2)};
431   if (sym1.attrs().test(Attr::PROTECTED) &&
432       !sym2.attrs().test(Attr::PROTECTED)) { // C8114
433     msg = "Equivalence set cannot contain '%s'"
434           " with PROTECTED attribute and '%s' without"_err_en_US;
435   } else if ((isDefaultNum1 && isDefaultNum2) || (isChar1 && isChar2)) {
436     // ok & standard conforming
437   } else if (!(isAnyNum1 || isChar1) &&
438       !(isAnyNum2 || isChar2)) { // C8110 - C8113
439     if (AreTkCompatibleTypes(type1, type2)) {
440       if (context_.ShouldWarn(LanguageFeature::EquivalenceSameNonSequence)) {
441         msg =
442             "nonstandard: Equivalence set contains '%s' and '%s' with same "
443             "type that is neither numeric nor character sequence type"_port_en_US;
444       }
445     } else {
446       msg = "Equivalence set cannot contain '%s' and '%s' with distinct types "
447             "that are not both numeric or character sequence types"_err_en_US;
448     }
449   } else if (isAnyNum1) {
450     if (isChar2) {
451       if (context_.ShouldWarn(
452               LanguageFeature::EquivalenceNumericWithCharacter)) {
453         msg = "nonstandard: Equivalence set contains '%s' that is numeric "
454               "sequence type and '%s' that is character"_port_en_US;
455       }
456     } else if (isAnyNum2 &&
457         context_.ShouldWarn(LanguageFeature::EquivalenceNonDefaultNumeric)) {
458       if (isDefaultNum1) {
459         msg =
460             "nonstandard: Equivalence set contains '%s' that is a default "
461             "numeric sequence type and '%s' that is numeric with non-default kind"_port_en_US;
462       } else if (!isDefaultNum2) {
463         msg = "nonstandard: Equivalence set contains '%s' and '%s' that are "
464               "numeric sequence types with non-default kinds"_port_en_US;
465       }
466     }
467   }
468   if (msg &&
469       (!context_.IsInModuleFile(source) ||
470           msg->severity() == parser::Severity::Error)) {
471     context_.Say(source, std::move(*msg), sym1.name(), sym2.name());
472     return false;
473   }
474   return true;
475 }
476 
477 // Move objects from src to sets_[dstIndex]
478 void EquivalenceSets::MergeInto(const parser::CharBlock &source,
479     EquivalenceSet &src, std::size_t dstIndex) {
480   EquivalenceSet &dst{sets_[dstIndex]};
481   PropagateSaveAttr(dst, src);
482   for (const auto &obj : src) {
483     dst.push_back(obj);
484     objectToSet_[obj] = dstIndex;
485   }
486   PropagateSaveAttr(src, dst);
487   src.clear();
488 }
489 
490 // If set has an object with this symbol, return it.
491 const EquivalenceObject *EquivalenceSets::Find(
492     const EquivalenceSet &set, const Symbol &symbol) {
493   for (const auto &obj : set) {
494     if (obj.symbol == symbol) {
495       return &obj;
496     }
497   }
498   return nullptr;
499 }
500 
501 bool EquivalenceSets::CheckDesignator(const parser::Designator &designator) {
502   return common::visit(
503       common::visitors{
504           [&](const parser::DataRef &x) {
505             return CheckDataRef(designator.source, x);
506           },
507           [&](const parser::Substring &x) {
508             const auto &dataRef{std::get<parser::DataRef>(x.t)};
509             const auto &range{std::get<parser::SubstringRange>(x.t)};
510             bool ok{CheckDataRef(designator.source, dataRef)};
511             if (const auto &lb{std::get<0>(range.t)}) {
512               ok &= CheckSubstringBound(lb->thing.thing.value(), true);
513             } else {
514               currObject_.substringStart = 1;
515             }
516             if (const auto &ub{std::get<1>(range.t)}) {
517               ok &= CheckSubstringBound(ub->thing.thing.value(), false);
518             }
519             return ok;
520           },
521       },
522       designator.u);
523 }
524 
525 bool EquivalenceSets::CheckDataRef(
526     const parser::CharBlock &source, const parser::DataRef &x) {
527   return common::visit(
528       common::visitors{
529           [&](const parser::Name &name) { return CheckObject(name); },
530           [&](const common::Indirection<parser::StructureComponent> &) {
531             context_.Say(source, // C8107
532                 "Derived type component '%s' is not allowed in an equivalence set"_err_en_US,
533                 source);
534             return false;
535           },
536           [&](const common::Indirection<parser::ArrayElement> &elem) {
537             bool ok{CheckDataRef(source, elem.value().base)};
538             for (const auto &subscript : elem.value().subscripts) {
539               ok &= common::visit(
540                   common::visitors{
541                       [&](const parser::SubscriptTriplet &) {
542                         context_.Say(source, // C924, R872
543                             "Array section '%s' is not allowed in an equivalence set"_err_en_US,
544                             source);
545                         return false;
546                       },
547                       [&](const parser::IntExpr &y) {
548                         return CheckArrayBound(y.thing.value());
549                       },
550                   },
551                   subscript.u);
552             }
553             return ok;
554           },
555           [&](const common::Indirection<parser::CoindexedNamedObject> &) {
556             context_.Say(source, // C924 (R872)
557                 "Coindexed object '%s' is not allowed in an equivalence set"_err_en_US,
558                 source);
559             return false;
560           },
561       },
562       x.u);
563 }
564 
565 static bool InCommonWithBind(const Symbol &symbol) {
566   if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
567     const Symbol *commonBlock{details->commonBlock()};
568     return commonBlock && commonBlock->attrs().test(Attr::BIND_C);
569   } else {
570     return false;
571   }
572 }
573 
574 // If symbol can't be in equivalence set report error and return false;
575 bool EquivalenceSets::CheckObject(const parser::Name &name) {
576   if (!name.symbol) {
577     return false; // an error has already occurred
578   }
579   currObject_.symbol = name.symbol;
580   parser::MessageFixedText msg;
581   const Symbol &symbol{*name.symbol};
582   if (symbol.owner().IsDerivedType()) { // C8107
583     msg = "Derived type component '%s'"
584           " is not allowed in an equivalence set"_err_en_US;
585   } else if (IsDummy(symbol)) { // C8106
586     msg = "Dummy argument '%s' is not allowed in an equivalence set"_err_en_US;
587   } else if (symbol.IsFuncResult()) { // C8106
588     msg = "Function result '%s' is not allow in an equivalence set"_err_en_US;
589   } else if (IsPointer(symbol)) { // C8106
590     msg = "Pointer '%s' is not allowed in an equivalence set"_err_en_US;
591   } else if (IsAllocatable(symbol)) { // C8106
592     msg = "Allocatable variable '%s'"
593           " is not allowed in an equivalence set"_err_en_US;
594   } else if (symbol.Corank() > 0) { // C8106
595     msg = "Coarray '%s' is not allowed in an equivalence set"_err_en_US;
596   } else if (symbol.has<UseDetails>()) { // C8115
597     msg = "Use-associated variable '%s'"
598           " is not allowed in an equivalence set"_err_en_US;
599   } else if (symbol.attrs().test(Attr::BIND_C)) { // C8106
600     msg = "Variable '%s' with BIND attribute"
601           " is not allowed in an equivalence set"_err_en_US;
602   } else if (symbol.attrs().test(Attr::TARGET)) { // C8108
603     msg = "Variable '%s' with TARGET attribute"
604           " is not allowed in an equivalence set"_err_en_US;
605   } else if (IsNamedConstant(symbol)) { // C8106
606     msg = "Named constant '%s' is not allowed in an equivalence set"_err_en_US;
607   } else if (InCommonWithBind(symbol)) { // C8106
608     msg = "Variable '%s' in common block with BIND attribute"
609           " is not allowed in an equivalence set"_err_en_US;
610   } else if (const auto *type{symbol.GetType()}) {
611     if (const auto *derived{type->AsDerived()}) {
612       if (const auto *comp{FindUltimateComponent(
613               *derived, IsAllocatableOrPointer)}) { // C8106
614         msg = IsPointer(*comp)
615             ? "Derived type object '%s' with pointer ultimate component"
616               " is not allowed in an equivalence set"_err_en_US
617             : "Derived type object '%s' with allocatable ultimate component"
618               " is not allowed in an equivalence set"_err_en_US;
619       } else if (!derived->typeSymbol().get<DerivedTypeDetails>().sequence()) {
620         msg = "Nonsequence derived type object '%s'"
621               " is not allowed in an equivalence set"_err_en_US;
622       }
623     } else if (IsAutomatic(symbol)) {
624       msg = "Automatic object '%s'"
625             " is not allowed in an equivalence set"_err_en_US;
626     }
627   }
628   if (!msg.text().empty()) {
629     context_.Say(name.source, std::move(msg), name.source);
630     return false;
631   }
632   return true;
633 }
634 
635 bool EquivalenceSets::CheckArrayBound(const parser::Expr &bound) {
636   MaybeExpr expr{
637       evaluate::Fold(context_.foldingContext(), AnalyzeExpr(context_, bound))};
638   if (!expr) {
639     return false;
640   }
641   if (expr->Rank() > 0) {
642     context_.Say(bound.source, // C924, R872
643         "Array with vector subscript '%s' is not allowed in an equivalence set"_err_en_US,
644         bound.source);
645     return false;
646   }
647   auto subscript{evaluate::ToInt64(*expr)};
648   if (!subscript) {
649     context_.Say(bound.source, // C8109
650         "Array with nonconstant subscript '%s' is not allowed in an equivalence set"_err_en_US,
651         bound.source);
652     return false;
653   }
654   currObject_.subscripts.push_back(*subscript);
655   return true;
656 }
657 
658 bool EquivalenceSets::CheckSubstringBound(
659     const parser::Expr &bound, bool isStart) {
660   MaybeExpr expr{
661       evaluate::Fold(context_.foldingContext(), AnalyzeExpr(context_, bound))};
662   if (!expr) {
663     return false;
664   }
665   auto subscript{evaluate::ToInt64(*expr)};
666   if (!subscript) {
667     context_.Say(bound.source, // C8109
668         "Substring with nonconstant bound '%s' is not allowed in an equivalence set"_err_en_US,
669         bound.source);
670     return false;
671   }
672   if (!isStart) {
673     auto start{currObject_.substringStart};
674     if (*subscript < (start ? *start : 1)) {
675       context_.Say(bound.source, // C8116
676           "Substring with zero length is not allowed in an equivalence set"_err_en_US);
677       return false;
678     }
679   } else if (*subscript != 1) {
680     currObject_.substringStart = *subscript;
681   }
682   return true;
683 }
684 
685 bool EquivalenceSets::IsCharacterSequenceType(const DeclTypeSpec *type) {
686   return IsSequenceType(type, [&](const IntrinsicTypeSpec &type) {
687     auto kind{evaluate::ToInt64(type.kind())};
688     return type.category() == TypeCategory::Character && kind &&
689         kind.value() == context_.GetDefaultKind(TypeCategory::Character);
690   });
691 }
692 
693 // Numeric or logical type of default kind or DOUBLE PRECISION or DOUBLE COMPLEX
694 bool EquivalenceSets::IsDefaultKindNumericType(const IntrinsicTypeSpec &type) {
695   if (auto kind{evaluate::ToInt64(type.kind())}) {
696     switch (type.category()) {
697     case TypeCategory::Integer:
698     case TypeCategory::Logical:
699       return *kind == context_.GetDefaultKind(TypeCategory::Integer);
700     case TypeCategory::Real:
701     case TypeCategory::Complex:
702       return *kind == context_.GetDefaultKind(TypeCategory::Real) ||
703           *kind == context_.doublePrecisionKind();
704     default:
705       return false;
706     }
707   }
708   return false;
709 }
710 
711 bool EquivalenceSets::IsDefaultNumericSequenceType(const DeclTypeSpec *type) {
712   return IsSequenceType(type, [&](const IntrinsicTypeSpec &type) {
713     return IsDefaultKindNumericType(type);
714   });
715 }
716 
717 bool EquivalenceSets::IsAnyNumericSequenceType(const DeclTypeSpec *type) {
718   return IsSequenceType(type, [&](const IntrinsicTypeSpec &type) {
719     return type.category() == TypeCategory::Logical ||
720         common::IsNumericTypeCategory(type.category());
721   });
722 }
723 
724 // Is type an intrinsic type that satisfies predicate or a sequence type
725 // whose components do.
726 bool EquivalenceSets::IsSequenceType(const DeclTypeSpec *type,
727     std::function<bool(const IntrinsicTypeSpec &)> predicate) {
728   if (!type) {
729     return false;
730   } else if (const IntrinsicTypeSpec * intrinsic{type->AsIntrinsic()}) {
731     return predicate(*intrinsic);
732   } else if (const DerivedTypeSpec * derived{type->AsDerived()}) {
733     for (const auto &pair : *derived->typeSymbol().scope()) {
734       const Symbol &component{*pair.second};
735       if (IsAllocatableOrPointer(component) ||
736           !IsSequenceType(component.GetType(), predicate)) {
737         return false;
738       }
739     }
740     return true;
741   } else {
742     return false;
743   }
744 }
745 
746 // MapSubprogramToNewSymbols() relies on the following recursive symbol/scope
747 // copying infrastructure to duplicate an interface's symbols and map all
748 // of the symbol references in their contained expressions and interfaces
749 // to the new symbols.
750 
751 struct SymbolAndTypeMappings {
752   std::map<const Symbol *, const Symbol *> symbolMap;
753   std::map<const DeclTypeSpec *, const DeclTypeSpec *> typeMap;
754 };
755 
756 class SymbolMapper : public evaluate::AnyTraverse<SymbolMapper, bool> {
757 public:
758   using Base = evaluate::AnyTraverse<SymbolMapper, bool>;
759   SymbolMapper(Scope &scope, SymbolAndTypeMappings &map)
760       : Base{*this}, scope_{scope}, map_{map} {}
761   using Base::operator();
762   bool operator()(const SymbolRef &ref) const {
763     if (const Symbol *mapped{MapSymbol(*ref)}) {
764       const_cast<SymbolRef &>(ref) = *mapped;
765     }
766     return false;
767   }
768   bool operator()(const Symbol &x) const {
769     if (MapSymbol(x)) {
770       DIE("SymbolMapper hit symbol outside SymbolRef");
771     }
772     return false;
773   }
774   void MapSymbolExprs(Symbol &);
775 
776 private:
777   void MapParamValue(ParamValue &param) const { (*this)(param.GetExplicit()); }
778   void MapBound(Bound &bound) const { (*this)(bound.GetExplicit()); }
779   void MapShapeSpec(ShapeSpec &spec) const {
780     MapBound(spec.lbound());
781     MapBound(spec.ubound());
782   }
783   const Symbol *MapSymbol(const Symbol &) const;
784   const Symbol *MapSymbol(const Symbol *) const;
785   const DeclTypeSpec *MapType(const DeclTypeSpec &);
786   const DeclTypeSpec *MapType(const DeclTypeSpec *);
787   const Symbol *MapInterface(const Symbol *);
788 
789   Scope &scope_;
790   SymbolAndTypeMappings &map_;
791 };
792 
793 void SymbolMapper::MapSymbolExprs(Symbol &symbol) {
794   if (auto *object{symbol.detailsIf<ObjectEntityDetails>()}) {
795     if (const DeclTypeSpec *type{object->type()}) {
796       if (const DeclTypeSpec *newType{MapType(*type)}) {
797         object->ReplaceType(*newType);
798       }
799     }
800   }
801   common::visit(common::visitors{[&](ObjectEntityDetails &object) {
802                                    for (ShapeSpec &spec : object.shape()) {
803                                      MapShapeSpec(spec);
804                                    }
805                                    for (ShapeSpec &spec : object.coshape()) {
806                                      MapShapeSpec(spec);
807                                    }
808                                  },
809                     [&](ProcEntityDetails &proc) {
810                       if (const Symbol *mappedSymbol{
811                               MapInterface(proc.interface().symbol())}) {
812                         proc.interface().set_symbol(*mappedSymbol);
813                       } else if (const DeclTypeSpec *mappedType{
814                                      MapType(proc.interface().type())}) {
815                         proc.interface().set_type(*mappedType);
816                       }
817                       if (proc.init()) {
818                         if (const Symbol *mapped{MapSymbol(*proc.init())}) {
819                           proc.set_init(*mapped);
820                         }
821                       }
822                     },
823                     [&](const HostAssocDetails &hostAssoc) {
824                       if (const Symbol *mapped{MapSymbol(hostAssoc.symbol())}) {
825                         symbol.set_details(HostAssocDetails{*mapped});
826                       }
827                     },
828                     [](const auto &) {}},
829       symbol.details());
830 }
831 
832 const Symbol *SymbolMapper::MapSymbol(const Symbol &symbol) const {
833   if (auto iter{map_.symbolMap.find(&symbol)}; iter != map_.symbolMap.end()) {
834     return iter->second;
835   }
836   return nullptr;
837 }
838 
839 const Symbol *SymbolMapper::MapSymbol(const Symbol *symbol) const {
840   return symbol ? MapSymbol(*symbol) : nullptr;
841 }
842 
843 const DeclTypeSpec *SymbolMapper::MapType(const DeclTypeSpec &type) {
844   if (auto iter{map_.typeMap.find(&type)}; iter != map_.typeMap.end()) {
845     return iter->second;
846   }
847   const DeclTypeSpec *newType{nullptr};
848   if (type.category() == DeclTypeSpec::Category::Character) {
849     const CharacterTypeSpec &charType{type.characterTypeSpec()};
850     if (charType.length().GetExplicit()) {
851       ParamValue newLen{charType.length()};
852       (*this)(newLen.GetExplicit());
853       newType = &scope_.MakeCharacterType(
854           std::move(newLen), KindExpr{charType.kind()});
855     }
856   } else if (const DerivedTypeSpec *derived{type.AsDerived()}) {
857     if (!derived->parameters().empty()) {
858       DerivedTypeSpec newDerived{derived->name(), derived->typeSymbol()};
859       newDerived.CookParameters(scope_.context().foldingContext());
860       for (const auto &[paramName, paramValue] : derived->parameters()) {
861         ParamValue newParamValue{paramValue};
862         MapParamValue(newParamValue);
863         newDerived.AddParamValue(paramName, std::move(newParamValue));
864       }
865       // Scope::InstantiateDerivedTypes() instantiates it later.
866       newType = &scope_.MakeDerivedType(type.category(), std::move(newDerived));
867     }
868   }
869   if (newType) {
870     map_.typeMap[&type] = newType;
871   }
872   return newType;
873 }
874 
875 const DeclTypeSpec *SymbolMapper::MapType(const DeclTypeSpec *type) {
876   return type ? MapType(*type) : nullptr;
877 }
878 
879 const Symbol *SymbolMapper::MapInterface(const Symbol *interface) {
880   if (const Symbol *mapped{MapSymbol(interface)}) {
881     return mapped;
882   }
883   if (interface) {
884     if (&interface->owner() != &scope_) {
885       return interface;
886     } else if (const auto *subp{interface->detailsIf<SubprogramDetails>()};
887                subp && subp->isInterface()) {
888       if (Symbol *newSymbol{scope_.CopySymbol(*interface)}) {
889         newSymbol->get<SubprogramDetails>().set_isInterface(true);
890         map_.symbolMap[interface] = newSymbol;
891         Scope &newScope{scope_.MakeScope(Scope::Kind::Subprogram, newSymbol)};
892         MapSubprogramToNewSymbols(*interface, *newSymbol, newScope, &map_);
893         return newSymbol;
894       }
895     }
896   }
897   return nullptr;
898 }
899 
900 void MapSubprogramToNewSymbols(const Symbol &oldSymbol, Symbol &newSymbol,
901     Scope &newScope, SymbolAndTypeMappings *mappings) {
902   SymbolAndTypeMappings newMappings;
903   if (!mappings) {
904     mappings = &newMappings;
905   }
906   mappings->symbolMap[&oldSymbol] = &newSymbol;
907   const auto &oldDetails{oldSymbol.get<SubprogramDetails>()};
908   auto &newDetails{newSymbol.get<SubprogramDetails>()};
909   for (const Symbol *dummyArg : oldDetails.dummyArgs()) {
910     if (!dummyArg) {
911       newDetails.add_alternateReturn();
912     } else if (Symbol *copy{newScope.CopySymbol(*dummyArg)}) {
913       newDetails.add_dummyArg(*copy);
914       mappings->symbolMap[dummyArg] = copy;
915     }
916   }
917   if (oldDetails.isFunction()) {
918     newScope.erase(newSymbol.name());
919     if (Symbol *copy{newScope.CopySymbol(oldDetails.result())}) {
920       newDetails.set_result(*copy);
921       mappings->symbolMap[&oldDetails.result()] = copy;
922     }
923   }
924   SymbolMapper mapper{newScope, *mappings};
925   for (auto &[_, ref] : newScope) {
926     mapper.MapSymbolExprs(*ref);
927   }
928   newScope.InstantiateDerivedTypes();
929 }
930 
931 } // namespace Fortran::semantics
932