1 //===-- lib/Semantics/check-call.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 "check-call.h"
10 #include "pointer-assignment.h"
11 #include "flang/Evaluate/characteristics.h"
12 #include "flang/Evaluate/check-expression.h"
13 #include "flang/Evaluate/shape.h"
14 #include "flang/Evaluate/tools.h"
15 #include "flang/Parser/characters.h"
16 #include "flang/Parser/message.h"
17 #include "flang/Semantics/scope.h"
18 #include "flang/Semantics/tools.h"
19 #include <map>
20 #include <string>
21 
22 using namespace Fortran::parser::literals;
23 namespace characteristics = Fortran::evaluate::characteristics;
24 
25 namespace Fortran::semantics {
26 
27 static void CheckImplicitInterfaceArg(
28     evaluate::ActualArgument &arg, parser::ContextualMessages &messages) {
29   if (auto kw{arg.keyword()}) {
30     messages.Say(*kw,
31         "Keyword '%s=' may not appear in a reference to a procedure with an implicit interface"_err_en_US,
32         *kw);
33   }
34   if (auto type{arg.GetType()}) {
35     if (type->IsAssumedType()) {
36       messages.Say(
37           "Assumed type argument requires an explicit interface"_err_en_US);
38     } else if (type->IsPolymorphic()) {
39       messages.Say(
40           "Polymorphic argument requires an explicit interface"_err_en_US);
41     } else if (const DerivedTypeSpec * derived{GetDerivedTypeSpec(type)}) {
42       if (!derived->parameters().empty()) {
43         messages.Say(
44             "Parameterized derived type argument requires an explicit interface"_err_en_US);
45       }
46     }
47   }
48   if (const auto *expr{arg.UnwrapExpr()}) {
49     if (auto named{evaluate::ExtractNamedEntity(*expr)}) {
50       const Symbol &symbol{named->GetLastSymbol()};
51       if (symbol.Corank() > 0) {
52         messages.Say(
53             "Coarray argument requires an explicit interface"_err_en_US);
54       }
55       if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
56         if (details->IsAssumedRank()) {
57           messages.Say(
58               "Assumed rank argument requires an explicit interface"_err_en_US);
59         }
60       }
61       if (symbol.attrs().test(Attr::ASYNCHRONOUS)) {
62         messages.Say(
63             "ASYNCHRONOUS argument requires an explicit interface"_err_en_US);
64       }
65       if (symbol.attrs().test(Attr::VOLATILE)) {
66         messages.Say(
67             "VOLATILE argument requires an explicit interface"_err_en_US);
68       }
69     }
70   }
71 }
72 
73 // When scalar CHARACTER actual arguments are known to be short,
74 // we extend them on the right with spaces and a warning.
75 static void PadShortCharacterActual(evaluate::Expr<evaluate::SomeType> &actual,
76     const characteristics::TypeAndShape &dummyType,
77     characteristics::TypeAndShape &actualType,
78     evaluate::FoldingContext &context, parser::ContextualMessages &messages) {
79   if (dummyType.type().category() == TypeCategory::Character &&
80       actualType.type().category() == TypeCategory::Character &&
81       dummyType.type().kind() == actualType.type().kind() &&
82       GetRank(actualType.shape()) == 0) {
83     if (dummyType.LEN() && actualType.LEN()) {
84       auto dummyLength{ToInt64(Fold(context, common::Clone(*dummyType.LEN())))};
85       auto actualLength{
86           ToInt64(Fold(context, common::Clone(*actualType.LEN())))};
87       if (dummyLength && actualLength && *actualLength < *dummyLength) {
88         messages.Say(
89             "Actual length '%jd' is less than expected length '%jd'"_en_US,
90             *actualLength, *dummyLength);
91         auto converted{ConvertToType(dummyType.type(), std::move(actual))};
92         CHECK(converted);
93         actual = std::move(*converted);
94         actualType.set_LEN(SubscriptIntExpr{*dummyLength});
95       }
96     }
97   }
98 }
99 
100 // Automatic conversion of different-kind INTEGER scalar actual
101 // argument expressions (not variables) to INTEGER scalar dummies.
102 // We return nonstandard INTEGER(8) results from intrinsic functions
103 // like SIZE() by default in order to facilitate the use of large
104 // arrays.  Emit a warning when downconverting.
105 static void ConvertIntegerActual(evaluate::Expr<evaluate::SomeType> &actual,
106     const characteristics::TypeAndShape &dummyType,
107     characteristics::TypeAndShape &actualType,
108     parser::ContextualMessages &messages) {
109   if (dummyType.type().category() == TypeCategory::Integer &&
110       actualType.type().category() == TypeCategory::Integer &&
111       dummyType.type().kind() != actualType.type().kind() &&
112       GetRank(dummyType.shape()) == 0 && GetRank(actualType.shape()) == 0 &&
113       !evaluate::IsVariable(actual)) {
114     auto converted{
115         evaluate::ConvertToType(dummyType.type(), std::move(actual))};
116     CHECK(converted);
117     actual = std::move(*converted);
118     if (dummyType.type().kind() < actualType.type().kind()) {
119       messages.Say(
120           "Actual argument scalar expression of type INTEGER(%d) was converted to smaller dummy argument type INTEGER(%d)"_en_US,
121           actualType.type().kind(), dummyType.type().kind());
122     }
123     actualType = dummyType;
124   }
125 }
126 
127 static bool DefersSameTypeParameters(
128     const DerivedTypeSpec &actual, const DerivedTypeSpec &dummy) {
129   for (const auto &pair : actual.parameters()) {
130     const ParamValue &actualValue{pair.second};
131     const ParamValue *dummyValue{dummy.FindParameter(pair.first)};
132     if (!dummyValue || (actualValue.isDeferred() != dummyValue->isDeferred())) {
133       return false;
134     }
135   }
136   return true;
137 }
138 
139 static void CheckExplicitDataArg(const characteristics::DummyDataObject &dummy,
140     const std::string &dummyName, evaluate::Expr<evaluate::SomeType> &actual,
141     characteristics::TypeAndShape &actualType, bool isElemental,
142     bool actualIsArrayElement, evaluate::FoldingContext &context,
143     const Scope *scope, const evaluate::SpecificIntrinsic *intrinsic) {
144 
145   // Basic type & rank checking
146   parser::ContextualMessages &messages{context.messages()};
147   PadShortCharacterActual(actual, dummy.type, actualType, context, messages);
148   ConvertIntegerActual(actual, dummy.type, actualType, messages);
149   bool typesCompatible{dummy.type.type().IsTkCompatibleWith(actualType.type())};
150   if (typesCompatible) {
151     if (isElemental) {
152     } else if (dummy.type.attrs().test(
153                    characteristics::TypeAndShape::Attr::AssumedRank)) {
154     } else if (!dummy.type.attrs().test(
155                    characteristics::TypeAndShape::Attr::AssumedShape) &&
156         (actualType.Rank() > 0 || actualIsArrayElement)) {
157       // Sequence association (15.5.2.11) applies -- rank need not match
158       // if the actual argument is an array or array element designator.
159     } else {
160       // Let CheckConformance accept scalars; storage association
161       // cases are checked here below.
162       CheckConformance(messages, dummy.type.shape(), actualType.shape(),
163           "dummy argument", "actual argument", true, true);
164     }
165   } else {
166     const auto &len{actualType.LEN()};
167     messages.Say(
168         "Actual argument type '%s' is not compatible with dummy argument type '%s'"_err_en_US,
169         actualType.type().AsFortran(len ? len->AsFortran() : ""),
170         dummy.type.type().AsFortran());
171   }
172 
173   bool actualIsPolymorphic{actualType.type().IsPolymorphic()};
174   bool dummyIsPolymorphic{dummy.type.type().IsPolymorphic()};
175   bool actualIsCoindexed{ExtractCoarrayRef(actual).has_value()};
176   bool actualIsAssumedSize{actualType.attrs().test(
177       characteristics::TypeAndShape::Attr::AssumedSize)};
178   bool dummyIsAssumedSize{dummy.type.attrs().test(
179       characteristics::TypeAndShape::Attr::AssumedSize)};
180   bool dummyIsAsynchronous{
181       dummy.attrs.test(characteristics::DummyDataObject::Attr::Asynchronous)};
182   bool dummyIsVolatile{
183       dummy.attrs.test(characteristics::DummyDataObject::Attr::Volatile)};
184   bool dummyIsValue{
185       dummy.attrs.test(characteristics::DummyDataObject::Attr::Value)};
186 
187   if (actualIsPolymorphic && dummyIsPolymorphic &&
188       actualIsCoindexed) { // 15.5.2.4(2)
189     messages.Say(
190         "Coindexed polymorphic object may not be associated with a polymorphic %s"_err_en_US,
191         dummyName);
192   }
193   if (actualIsPolymorphic && !dummyIsPolymorphic &&
194       actualIsAssumedSize) { // 15.5.2.4(2)
195     messages.Say(
196         "Assumed-size polymorphic array may not be associated with a monomorphic %s"_err_en_US,
197         dummyName);
198   }
199 
200   // Derived type actual argument checks
201   const Symbol *actualFirstSymbol{evaluate::GetFirstSymbol(actual)};
202   bool actualIsAsynchronous{
203       actualFirstSymbol && actualFirstSymbol->attrs().test(Attr::ASYNCHRONOUS)};
204   bool actualIsVolatile{
205       actualFirstSymbol && actualFirstSymbol->attrs().test(Attr::VOLATILE)};
206   if (const auto *derived{evaluate::GetDerivedTypeSpec(actualType.type())}) {
207     if (dummy.type.type().IsAssumedType()) {
208       if (!derived->parameters().empty()) { // 15.5.2.4(2)
209         messages.Say(
210             "Actual argument associated with TYPE(*) %s may not have a parameterized derived type"_err_en_US,
211             dummyName);
212       }
213       if (const Symbol *
214           tbp{FindImmediateComponent(*derived, [](const Symbol &symbol) {
215             return symbol.has<ProcBindingDetails>();
216           })}) { // 15.5.2.4(2)
217         evaluate::SayWithDeclaration(messages, *tbp,
218             "Actual argument associated with TYPE(*) %s may not have type-bound procedure '%s'"_err_en_US,
219             dummyName, tbp->name());
220       }
221       const auto &finals{
222           derived->typeSymbol().get<DerivedTypeDetails>().finals()};
223       if (!finals.empty()) { // 15.5.2.4(2)
224         if (auto *msg{messages.Say(
225                 "Actual argument associated with TYPE(*) %s may not have derived type '%s' with FINAL subroutine '%s'"_err_en_US,
226                 dummyName, derived->typeSymbol().name(),
227                 finals.begin()->first)}) {
228           msg->Attach(finals.begin()->first,
229               "FINAL subroutine '%s' in derived type '%s'"_en_US,
230               finals.begin()->first, derived->typeSymbol().name());
231         }
232       }
233     }
234     if (actualIsCoindexed) {
235       if (dummy.intent != common::Intent::In && !dummyIsValue) {
236         if (auto bad{
237                 FindAllocatableUltimateComponent(*derived)}) { // 15.5.2.4(6)
238           evaluate::SayWithDeclaration(messages, *bad,
239               "Coindexed actual argument with ALLOCATABLE ultimate component '%s' must be associated with a %s with VALUE or INTENT(IN) attributes"_err_en_US,
240               bad.BuildResultDesignatorName(), dummyName);
241         }
242       }
243       if (auto coarrayRef{evaluate::ExtractCoarrayRef(actual)}) { // C1537
244         const Symbol &coarray{coarrayRef->GetLastSymbol()};
245         if (const DeclTypeSpec * type{coarray.GetType()}) {
246           if (const DerivedTypeSpec * derived{type->AsDerived()}) {
247             if (auto bad{semantics::FindPointerUltimateComponent(*derived)}) {
248               evaluate::SayWithDeclaration(messages, coarray,
249                   "Coindexed object '%s' with POINTER ultimate component '%s' cannot be associated with %s"_err_en_US,
250                   coarray.name(), bad.BuildResultDesignatorName(), dummyName);
251             }
252           }
253         }
254       }
255     }
256     if (actualIsVolatile != dummyIsVolatile) { // 15.5.2.4(22)
257       if (auto bad{semantics::FindCoarrayUltimateComponent(*derived)}) {
258         evaluate::SayWithDeclaration(messages, *bad,
259             "VOLATILE attribute must match for %s when actual argument has a coarray ultimate component '%s'"_err_en_US,
260             dummyName, bad.BuildResultDesignatorName());
261       }
262     }
263   }
264 
265   // Rank and shape checks
266   const auto *actualLastSymbol{evaluate::GetLastSymbol(actual)};
267   if (actualLastSymbol) {
268     actualLastSymbol = GetAssociationRoot(*actualLastSymbol);
269   }
270   const ObjectEntityDetails *actualLastObject{actualLastSymbol
271           ? actualLastSymbol->GetUltimate().detailsIf<ObjectEntityDetails>()
272           : nullptr};
273   int actualRank{evaluate::GetRank(actualType.shape())};
274   bool actualIsPointer{(actualLastSymbol && IsPointer(*actualLastSymbol)) ||
275       evaluate::IsNullPointer(actual)};
276   if (dummy.type.attrs().test(
277           characteristics::TypeAndShape::Attr::AssumedShape)) {
278     // 15.5.2.4(16)
279     if (actualRank == 0) {
280       messages.Say(
281           "Scalar actual argument may not be associated with assumed-shape %s"_err_en_US,
282           dummyName);
283     }
284     if (actualIsAssumedSize && actualLastSymbol) {
285       evaluate::SayWithDeclaration(messages, *actualLastSymbol,
286           "Assumed-size array may not be associated with assumed-shape %s"_err_en_US,
287           dummyName);
288     }
289   } else if (actualRank == 0 && dummy.type.Rank() > 0) {
290     // Actual is scalar, dummy is an array.  15.5.2.4(14), 15.5.2.11
291     if (actualIsCoindexed) {
292       messages.Say(
293           "Coindexed scalar actual argument must be associated with a scalar %s"_err_en_US,
294           dummyName);
295     }
296     if (actualLastSymbol && actualLastSymbol->Rank() == 0 &&
297         !(dummy.type.type().IsAssumedType() && dummyIsAssumedSize)) {
298       messages.Say(
299           "Whole scalar actual argument may not be associated with a %s array"_err_en_US,
300           dummyName);
301     }
302     if (actualIsPolymorphic) {
303       messages.Say(
304           "Polymorphic scalar may not be associated with a %s array"_err_en_US,
305           dummyName);
306     }
307     if (actualIsPointer) {
308       messages.Say(
309           "Scalar POINTER target may not be associated with a %s array"_err_en_US,
310           dummyName);
311     }
312     if (actualLastObject && actualLastObject->IsAssumedShape()) {
313       messages.Say(
314           "Element of assumed-shape array may not be associated with a %s array"_err_en_US,
315           dummyName);
316     }
317   }
318   if (actualLastObject && actualLastObject->IsCoarray() &&
319       IsAllocatable(*actualLastSymbol) && dummy.intent == common::Intent::Out &&
320       !(intrinsic &&
321           evaluate::AcceptsIntentOutAllocatableCoarray(
322               intrinsic->name))) { // C846
323     messages.Say(
324         "ALLOCATABLE coarray '%s' may not be associated with INTENT(OUT) %s"_err_en_US,
325         actualLastSymbol->name(), dummyName);
326   }
327 
328   // Definability
329   const char *reason{nullptr};
330   if (dummy.intent == common::Intent::Out) {
331     reason = "INTENT(OUT)";
332   } else if (dummy.intent == common::Intent::InOut) {
333     reason = "INTENT(IN OUT)";
334   } else if (dummyIsAsynchronous) {
335     reason = "ASYNCHRONOUS";
336   } else if (dummyIsVolatile) {
337     reason = "VOLATILE";
338   }
339   if (reason && scope) {
340     bool vectorSubscriptIsOk{isElemental || dummyIsValue}; // 15.5.2.4(21)
341     if (auto why{WhyNotModifiable(
342             messages.at(), actual, *scope, vectorSubscriptIsOk)}) {
343       if (auto *msg{messages.Say(
344               "Actual argument associated with %s %s must be definable"_err_en_US, // C1158
345               reason, dummyName)}) {
346         msg->Attach(*why);
347       }
348     }
349   }
350 
351   // Cases when temporaries might be needed but must not be permitted.
352   bool dummyIsPointer{
353       dummy.attrs.test(characteristics::DummyDataObject::Attr::Pointer)};
354   bool dummyIsContiguous{
355       dummy.attrs.test(characteristics::DummyDataObject::Attr::Contiguous)};
356   bool actualIsContiguous{IsSimplyContiguous(actual, context)};
357   bool dummyIsAssumedRank{dummy.type.attrs().test(
358       characteristics::TypeAndShape::Attr::AssumedRank)};
359   bool dummyIsAssumedShape{dummy.type.attrs().test(
360       characteristics::TypeAndShape::Attr::AssumedShape)};
361   if ((actualIsAsynchronous || actualIsVolatile) &&
362       (dummyIsAsynchronous || dummyIsVolatile) && !dummyIsValue) {
363     if (actualIsCoindexed) { // C1538
364       messages.Say(
365           "Coindexed ASYNCHRONOUS or VOLATILE actual argument may not be associated with %s with ASYNCHRONOUS or VOLATILE attributes unless VALUE"_err_en_US,
366           dummyName);
367     }
368     if (actualRank > 0 && !actualIsContiguous) {
369       if (dummyIsContiguous ||
370           !(dummyIsAssumedShape || dummyIsAssumedRank ||
371               (actualIsPointer && dummyIsPointer))) { // C1539 & C1540
372         messages.Say(
373             "ASYNCHRONOUS or VOLATILE actual argument that is not simply contiguous may not be associated with a contiguous %s"_err_en_US,
374             dummyName);
375       }
376     }
377   }
378 
379   // 15.5.2.6 -- dummy is ALLOCATABLE
380   bool dummyIsAllocatable{
381       dummy.attrs.test(characteristics::DummyDataObject::Attr::Allocatable)};
382   bool actualIsAllocatable{
383       actualLastSymbol && IsAllocatable(*actualLastSymbol)};
384   if (dummyIsAllocatable) {
385     if (!actualIsAllocatable) {
386       messages.Say(
387           "ALLOCATABLE %s must be associated with an ALLOCATABLE actual argument"_err_en_US,
388           dummyName);
389     }
390     if (actualIsAllocatable && actualIsCoindexed &&
391         dummy.intent != common::Intent::In) {
392       messages.Say(
393           "ALLOCATABLE %s must have INTENT(IN) to be associated with a coindexed actual argument"_err_en_US,
394           dummyName);
395     }
396     if (!actualIsCoindexed && actualLastSymbol &&
397         actualLastSymbol->Corank() != dummy.type.corank()) {
398       messages.Say(
399           "ALLOCATABLE %s has corank %d but actual argument has corank %d"_err_en_US,
400           dummyName, dummy.type.corank(), actualLastSymbol->Corank());
401     }
402   }
403 
404   // 15.5.2.7 -- dummy is POINTER
405   if (dummyIsPointer) {
406     if (dummyIsContiguous && !actualIsContiguous) {
407       messages.Say(
408           "Actual argument associated with CONTIGUOUS POINTER %s must be simply contiguous"_err_en_US,
409           dummyName);
410     }
411     if (!actualIsPointer) {
412       if (dummy.intent == common::Intent::In) {
413         semantics::CheckPointerAssignment(
414             context, parser::CharBlock{}, dummyName, dummy, actual);
415       } else {
416         messages.Say(
417             "Actual argument associated with POINTER %s must also be POINTER unless INTENT(IN)"_err_en_US,
418             dummyName);
419       }
420     }
421   }
422 
423   // 15.5.2.5 -- actual & dummy are both POINTER or both ALLOCATABLE
424   if ((actualIsPointer && dummyIsPointer) ||
425       (actualIsAllocatable && dummyIsAllocatable)) {
426     bool actualIsUnlimited{actualType.type().IsUnlimitedPolymorphic()};
427     bool dummyIsUnlimited{dummy.type.type().IsUnlimitedPolymorphic()};
428     if (actualIsUnlimited != dummyIsUnlimited) {
429       if (typesCompatible) {
430         messages.Say(
431             "If a POINTER or ALLOCATABLE dummy or actual argument is unlimited polymorphic, both must be so"_err_en_US);
432       }
433     } else if (dummyIsPolymorphic != actualIsPolymorphic) {
434       if (dummy.intent == common::Intent::In && typesCompatible) {
435         // extension: allow with warning, rule is only relevant for definables
436         messages.Say(
437             "If a POINTER or ALLOCATABLE dummy or actual argument is polymorphic, both should be so"_en_US);
438       } else {
439         messages.Say(
440             "If a POINTER or ALLOCATABLE dummy or actual argument is polymorphic, both must be so"_err_en_US);
441       }
442     } else if (!actualIsUnlimited && typesCompatible) {
443       if (!actualType.type().IsTkCompatibleWith(dummy.type.type())) {
444         if (dummy.intent == common::Intent::In) {
445           // extension: allow with warning, rule is only relevant for definables
446           messages.Say(
447               "POINTER or ALLOCATABLE dummy and actual arguments should have the same declared type and kind"_en_US);
448         } else {
449           messages.Say(
450               "POINTER or ALLOCATABLE dummy and actual arguments must have the same declared type and kind"_err_en_US);
451         }
452       }
453       if (const auto *derived{
454               evaluate::GetDerivedTypeSpec(actualType.type())}) {
455         if (!DefersSameTypeParameters(
456                 *derived, *evaluate::GetDerivedTypeSpec(dummy.type.type()))) {
457           messages.Say(
458               "Dummy and actual arguments must defer the same type parameters when POINTER or ALLOCATABLE"_err_en_US);
459         }
460       }
461     }
462   }
463 
464   // 15.5.2.8 -- coarray dummy arguments
465   if (dummy.type.corank() > 0) {
466     if (actualType.corank() == 0) {
467       messages.Say(
468           "Actual argument associated with coarray %s must be a coarray"_err_en_US,
469           dummyName);
470     }
471     if (dummyIsVolatile) {
472       if (!actualIsVolatile) {
473         messages.Say(
474             "non-VOLATILE coarray may not be associated with VOLATILE coarray %s"_err_en_US,
475             dummyName);
476       }
477     } else {
478       if (actualIsVolatile) {
479         messages.Say(
480             "VOLATILE coarray may not be associated with non-VOLATILE coarray %s"_err_en_US,
481             dummyName);
482       }
483     }
484     if (actualRank == dummy.type.Rank() && !actualIsContiguous) {
485       if (dummyIsContiguous) {
486         messages.Say(
487             "Actual argument associated with a CONTIGUOUS coarray %s must be simply contiguous"_err_en_US,
488             dummyName);
489       } else if (!dummyIsAssumedShape && !dummyIsAssumedRank) {
490         messages.Say(
491             "Actual argument associated with coarray %s (not assumed shape or rank) must be simply contiguous"_err_en_US,
492             dummyName);
493       }
494     }
495   }
496 }
497 
498 static void CheckProcedureArg(evaluate::ActualArgument &arg,
499     const characteristics::DummyProcedure &proc, const std::string &dummyName,
500     evaluate::FoldingContext &context) {
501   parser::ContextualMessages &messages{context.messages()};
502   const characteristics::Procedure &interface{proc.procedure.value()};
503   if (const auto *expr{arg.UnwrapExpr()}) {
504     bool dummyIsPointer{
505         proc.attrs.test(characteristics::DummyProcedure::Attr::Pointer)};
506     const auto *argProcDesignator{
507         std::get_if<evaluate::ProcedureDesignator>(&expr->u)};
508     const auto *argProcSymbol{
509         argProcDesignator ? argProcDesignator->GetSymbol() : nullptr};
510     if (auto argChars{characteristics::DummyArgument::FromActual(
511             "actual argument", *expr, context)}) {
512       if (!argChars->IsTypelessIntrinsicDummy()) {
513         if (auto *argProc{
514                 std::get_if<characteristics::DummyProcedure>(&argChars->u)}) {
515           characteristics::Procedure &argInterface{argProc->procedure.value()};
516           argInterface.attrs.reset(
517               characteristics::Procedure::Attr::NullPointer);
518           if (!argProcSymbol || argProcSymbol->attrs().test(Attr::INTRINSIC)) {
519             // It's ok to pass ELEMENTAL unrestricted intrinsic functions.
520             argInterface.attrs.reset(
521                 characteristics::Procedure::Attr::Elemental);
522           } else if (argInterface.attrs.test(
523                          characteristics::Procedure::Attr::Elemental)) {
524             if (argProcSymbol) { // C1533
525               evaluate::SayWithDeclaration(messages, *argProcSymbol,
526                   "Non-intrinsic ELEMENTAL procedure '%s' may not be passed as an actual argument"_err_en_US,
527                   argProcSymbol->name());
528               return; // avoid piling on with checks below
529             } else {
530               argInterface.attrs.reset(
531                   characteristics::Procedure::Attr::NullPointer);
532             }
533           }
534           if (!interface.IsPure()) {
535             // 15.5.2.9(1): if dummy is not pure, actual need not be.
536             argInterface.attrs.reset(characteristics::Procedure::Attr::Pure);
537           }
538           if (interface.HasExplicitInterface()) {
539             if (interface != argInterface) {
540               messages.Say(
541                   "Actual argument procedure has interface incompatible with %s"_err_en_US,
542                   dummyName);
543             }
544           } else { // 15.5.2.9(2,3)
545             if (interface.IsSubroutine() && argInterface.IsFunction()) {
546               messages.Say(
547                   "Actual argument associated with procedure %s is a function but must be a subroutine"_err_en_US,
548                   dummyName);
549             } else if (interface.IsFunction()) {
550               if (argInterface.IsFunction()) {
551                 if (interface.functionResult != argInterface.functionResult) {
552                   messages.Say(
553                       "Actual argument function associated with procedure %s has incompatible result type"_err_en_US,
554                       dummyName);
555                 }
556               } else if (argInterface.IsSubroutine()) {
557                 messages.Say(
558                     "Actual argument associated with procedure %s is a subroutine but must be a function"_err_en_US,
559                     dummyName);
560               }
561             }
562           }
563         } else {
564           messages.Say(
565               "Actual argument associated with procedure %s is not a procedure"_err_en_US,
566               dummyName);
567         }
568       } else if (!(dummyIsPointer && IsNullPointer(*expr))) {
569         messages.Say(
570             "Actual argument associated with procedure %s is not a procedure"_err_en_US,
571             dummyName);
572       }
573     }
574     if (interface.HasExplicitInterface()) {
575       if (dummyIsPointer) {
576         // 15.5.2.9(5) -- dummy procedure POINTER
577         // Interface compatibility has already been checked above by comparison.
578         if (proc.intent != common::Intent::In && !IsVariable(*expr)) {
579           messages.Say(
580               "Actual argument associated with procedure pointer %s must be a POINTER unless INTENT(IN)"_err_en_US,
581               dummyName);
582         }
583       } else { // 15.5.2.9(4) -- dummy procedure is not POINTER
584         if (!argProcDesignator) {
585           messages.Say(
586               "Actual argument associated with non-POINTER procedure %s must be a procedure (and not a procedure pointer)"_err_en_US,
587               dummyName);
588         }
589       }
590     }
591   } else {
592     messages.Say(
593         "Assumed-type argument may not be forwarded as procedure %s"_err_en_US,
594         dummyName);
595   }
596 }
597 
598 static void CheckExplicitInterfaceArg(evaluate::ActualArgument &arg,
599     const characteristics::DummyArgument &dummy,
600     const characteristics::Procedure &proc, evaluate::FoldingContext &context,
601     const Scope *scope, const evaluate::SpecificIntrinsic *intrinsic) {
602   auto &messages{context.messages()};
603   std::string dummyName{"dummy argument"};
604   if (!dummy.name.empty()) {
605     dummyName += " '"s + parser::ToLowerCaseLetters(dummy.name) + "='";
606   }
607   std::visit(
608       common::visitors{
609           [&](const characteristics::DummyDataObject &object) {
610             if (auto *expr{arg.UnwrapExpr()}) {
611               if (auto type{characteristics::TypeAndShape::Characterize(
612                       *expr, context)}) {
613                 arg.set_dummyIntent(object.intent);
614                 bool isElemental{object.type.Rank() == 0 && proc.IsElemental()};
615                 CheckExplicitDataArg(object, dummyName, *expr, *type,
616                     isElemental, IsArrayElement(*expr), context, scope,
617                     intrinsic);
618               } else if (object.type.type().IsTypelessIntrinsicArgument() &&
619                   std::holds_alternative<evaluate::BOZLiteralConstant>(
620                       expr->u)) {
621                 // ok
622               } else if (object.type.type().IsTypelessIntrinsicArgument() &&
623                   evaluate::IsNullPointer(*expr)) {
624                 // ok, calling ASSOCIATED(NULL())
625               } else {
626                 messages.Say(
627                     "Actual argument '%s' associated with %s is not a variable or typed expression"_err_en_US,
628                     expr->AsFortran(), dummyName);
629               }
630             } else {
631               const Symbol &assumed{DEREF(arg.GetAssumedTypeDummy())};
632               if (!object.type.type().IsAssumedType()) {
633                 messages.Say(
634                     "Assumed-type '%s' may be associated only with an assumed-type %s"_err_en_US,
635                     assumed.name(), dummyName);
636               } else if (const auto *details{
637                              assumed.detailsIf<ObjectEntityDetails>()}) {
638                 if (!(details->IsAssumedShape() || details->IsAssumedRank())) {
639                   messages.Say( // C711
640                       "Assumed-type '%s' must be either assumed shape or assumed rank to be associated with assumed-type %s"_err_en_US,
641                       assumed.name(), dummyName);
642                 }
643               }
644             }
645           },
646           [&](const characteristics::DummyProcedure &proc) {
647             CheckProcedureArg(arg, proc, dummyName, context);
648           },
649           [&](const characteristics::AlternateReturn &) {
650             // TODO check alternate return
651           },
652       },
653       dummy.u);
654 }
655 
656 static void RearrangeArguments(const characteristics::Procedure &proc,
657     evaluate::ActualArguments &actuals, parser::ContextualMessages &messages) {
658   CHECK(proc.HasExplicitInterface());
659   if (actuals.size() < proc.dummyArguments.size()) {
660     actuals.resize(proc.dummyArguments.size());
661   } else if (actuals.size() > proc.dummyArguments.size()) {
662     messages.Say(
663         "Too many actual arguments (%zd) passed to procedure that expects only %zd"_err_en_US,
664         actuals.size(), proc.dummyArguments.size());
665   }
666   std::map<std::string, evaluate::ActualArgument> kwArgs;
667   for (auto &x : actuals) {
668     if (x && x->keyword()) {
669       auto emplaced{
670           kwArgs.try_emplace(x->keyword()->ToString(), std::move(*x))};
671       if (!emplaced.second) {
672         messages.Say(*x->keyword(),
673             "Argument keyword '%s=' appears on more than one effective argument in this procedure reference"_err_en_US,
674             *x->keyword());
675       }
676       x.reset();
677     }
678   }
679   if (!kwArgs.empty()) {
680     int index{0};
681     for (const auto &dummy : proc.dummyArguments) {
682       if (!dummy.name.empty()) {
683         auto iter{kwArgs.find(dummy.name)};
684         if (iter != kwArgs.end()) {
685           evaluate::ActualArgument &x{iter->second};
686           if (actuals[index]) {
687             messages.Say(*x.keyword(),
688                 "Keyword argument '%s=' has already been specified positionally (#%d) in this procedure reference"_err_en_US,
689                 *x.keyword(), index + 1);
690           } else {
691             actuals[index] = std::move(x);
692           }
693           kwArgs.erase(iter);
694         }
695       }
696       ++index;
697     }
698     for (auto &bad : kwArgs) {
699       evaluate::ActualArgument &x{bad.second};
700       messages.Say(*x.keyword(),
701           "Argument keyword '%s=' is not recognized for this procedure reference"_err_en_US,
702           *x.keyword());
703     }
704   }
705 }
706 
707 static parser::Messages CheckExplicitInterface(
708     const characteristics::Procedure &proc, evaluate::ActualArguments &actuals,
709     const evaluate::FoldingContext &context, const Scope *scope,
710     const evaluate::SpecificIntrinsic *intrinsic) {
711   parser::Messages buffer;
712   parser::ContextualMessages messages{context.messages().at(), &buffer};
713   RearrangeArguments(proc, actuals, messages);
714   if (buffer.empty()) {
715     int index{0};
716     evaluate::FoldingContext localContext{context, messages};
717     for (auto &actual : actuals) {
718       const auto &dummy{proc.dummyArguments.at(index++)};
719       if (actual) {
720         CheckExplicitInterfaceArg(
721             *actual, dummy, proc, localContext, scope, intrinsic);
722       } else if (!dummy.IsOptional()) {
723         if (dummy.name.empty()) {
724           messages.Say(
725               "Dummy argument #%d is not OPTIONAL and is not associated with "
726               "an actual argument in this procedure reference"_err_en_US,
727               index);
728         } else {
729           messages.Say("Dummy argument '%s=' (#%d) is not OPTIONAL and is not "
730                        "associated with an actual argument in this procedure "
731                        "reference"_err_en_US,
732               dummy.name, index);
733         }
734       }
735     }
736   }
737   return buffer;
738 }
739 
740 parser::Messages CheckExplicitInterface(const characteristics::Procedure &proc,
741     evaluate::ActualArguments &actuals, const evaluate::FoldingContext &context,
742     const Scope &scope, const evaluate::SpecificIntrinsic *intrinsic) {
743   return CheckExplicitInterface(proc, actuals, context, &scope, intrinsic);
744 }
745 
746 bool CheckInterfaceForGeneric(const characteristics::Procedure &proc,
747     evaluate::ActualArguments &actuals,
748     const evaluate::FoldingContext &context) {
749   return CheckExplicitInterface(proc, actuals, context, nullptr, nullptr)
750       .empty();
751 }
752 
753 void CheckArguments(const characteristics::Procedure &proc,
754     evaluate::ActualArguments &actuals, evaluate::FoldingContext &context,
755     const Scope &scope, bool treatingExternalAsImplicit,
756     const evaluate::SpecificIntrinsic *intrinsic) {
757   bool explicitInterface{proc.HasExplicitInterface()};
758   if (explicitInterface) {
759     auto buffer{
760         CheckExplicitInterface(proc, actuals, context, scope, intrinsic)};
761     if (treatingExternalAsImplicit && !buffer.empty()) {
762       if (auto *msg{context.messages().Say(
763               "Warning: if the procedure's interface were explicit, this reference would be in error:"_en_US)}) {
764         buffer.AttachTo(*msg);
765       }
766     }
767     if (auto *msgs{context.messages().messages()}) {
768       msgs->Merge(std::move(buffer));
769     }
770   }
771   if (!explicitInterface || treatingExternalAsImplicit) {
772     for (auto &actual : actuals) {
773       if (actual) {
774         CheckImplicitInterfaceArg(*actual, context.messages());
775       }
776     }
777   }
778 }
779 } // namespace Fortran::semantics
780