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     evaluate::FoldingContext &context, const Scope *scope,
143     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 || IsArrayElement(actual))) {
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 = &ResolveAssociations(*actualLastSymbol);
269   }
270   const ObjectEntityDetails *actualLastObject{actualLastSymbol
271           ? actualLastSymbol->detailsIf<ObjectEntityDetails>()
272           : nullptr};
273   int actualRank{evaluate::GetRank(actualType.shape())};
274   bool actualIsPointer{evaluate::IsObjectPointer(actual, context)};
275   bool dummyIsAssumedRank{dummy.type.attrs().test(
276       characteristics::TypeAndShape::Attr::AssumedRank)};
277   if (dummy.type.attrs().test(
278           characteristics::TypeAndShape::Attr::AssumedShape)) {
279     // 15.5.2.4(16)
280     if (actualRank == 0) {
281       messages.Say(
282           "Scalar actual argument may not be associated with assumed-shape %s"_err_en_US,
283           dummyName);
284     }
285     if (actualIsAssumedSize && actualLastSymbol) {
286       evaluate::SayWithDeclaration(messages, *actualLastSymbol,
287           "Assumed-size array may not be associated with assumed-shape %s"_err_en_US,
288           dummyName);
289     }
290   } else if (actualRank == 0 && dummy.type.Rank() > 0) {
291     // Actual is scalar, dummy is an array.  15.5.2.4(14), 15.5.2.11
292     if (actualIsCoindexed) {
293       messages.Say(
294           "Coindexed scalar actual argument must be associated with a scalar %s"_err_en_US,
295           dummyName);
296     }
297     if (!IsArrayElement(actual) &&
298         !(actualType.type().category() == TypeCategory::Character &&
299             actualType.type().kind() == 1) &&
300         !(dummy.type.type().IsAssumedType() && dummyIsAssumedSize) &&
301         !dummyIsAssumedRank) {
302       messages.Say(
303           "Whole scalar actual argument may not be associated with a %s array"_err_en_US,
304           dummyName);
305     }
306     if (actualIsPolymorphic) {
307       messages.Say(
308           "Polymorphic scalar may not be associated with a %s array"_err_en_US,
309           dummyName);
310     }
311     if (actualIsPointer) {
312       messages.Say(
313           "Scalar POINTER target may not be associated with a %s array"_err_en_US,
314           dummyName);
315     }
316     if (actualLastObject && actualLastObject->IsAssumedShape()) {
317       messages.Say(
318           "Element of assumed-shape array may not be associated with a %s array"_err_en_US,
319           dummyName);
320     }
321   }
322   if (actualLastObject && actualLastObject->IsCoarray() &&
323       IsAllocatable(*actualLastSymbol) && dummy.intent == common::Intent::Out &&
324       !(intrinsic &&
325           evaluate::AcceptsIntentOutAllocatableCoarray(
326               intrinsic->name))) { // C846
327     messages.Say(
328         "ALLOCATABLE coarray '%s' may not be associated with INTENT(OUT) %s"_err_en_US,
329         actualLastSymbol->name(), dummyName);
330   }
331 
332   // Definability
333   const char *reason{nullptr};
334   if (dummy.intent == common::Intent::Out) {
335     reason = "INTENT(OUT)";
336   } else if (dummy.intent == common::Intent::InOut) {
337     reason = "INTENT(IN OUT)";
338   } else if (dummyIsAsynchronous) {
339     reason = "ASYNCHRONOUS";
340   } else if (dummyIsVolatile) {
341     reason = "VOLATILE";
342   }
343   if (reason && scope) {
344     bool vectorSubscriptIsOk{isElemental || dummyIsValue}; // 15.5.2.4(21)
345     if (auto why{WhyNotModifiable(
346             messages.at(), actual, *scope, vectorSubscriptIsOk)}) {
347       if (auto *msg{messages.Say(
348               "Actual argument associated with %s %s must be definable"_err_en_US, // C1158
349               reason, dummyName)}) {
350         msg->Attach(*why);
351       }
352     }
353   }
354 
355   // Cases when temporaries might be needed but must not be permitted.
356   bool dummyIsPointer{
357       dummy.attrs.test(characteristics::DummyDataObject::Attr::Pointer)};
358   bool dummyIsContiguous{
359       dummy.attrs.test(characteristics::DummyDataObject::Attr::Contiguous)};
360   bool actualIsContiguous{IsSimplyContiguous(actual, context)};
361   bool dummyIsAssumedShape{dummy.type.attrs().test(
362       characteristics::TypeAndShape::Attr::AssumedShape)};
363   if ((actualIsAsynchronous || actualIsVolatile) &&
364       (dummyIsAsynchronous || dummyIsVolatile) && !dummyIsValue) {
365     if (actualIsCoindexed) { // C1538
366       messages.Say(
367           "Coindexed ASYNCHRONOUS or VOLATILE actual argument may not be associated with %s with ASYNCHRONOUS or VOLATILE attributes unless VALUE"_err_en_US,
368           dummyName);
369     }
370     if (actualRank > 0 && !actualIsContiguous) {
371       if (dummyIsContiguous ||
372           !(dummyIsAssumedShape || dummyIsAssumedRank ||
373               (actualIsPointer && dummyIsPointer))) { // C1539 & C1540
374         messages.Say(
375             "ASYNCHRONOUS or VOLATILE actual argument that is not simply contiguous may not be associated with a contiguous %s"_err_en_US,
376             dummyName);
377       }
378     }
379   }
380 
381   // 15.5.2.6 -- dummy is ALLOCATABLE
382   bool dummyIsAllocatable{
383       dummy.attrs.test(characteristics::DummyDataObject::Attr::Allocatable)};
384   bool actualIsAllocatable{
385       actualLastSymbol && IsAllocatable(*actualLastSymbol)};
386   if (dummyIsAllocatable) {
387     if (!actualIsAllocatable) {
388       messages.Say(
389           "ALLOCATABLE %s must be associated with an ALLOCATABLE actual argument"_err_en_US,
390           dummyName);
391     }
392     if (actualIsAllocatable && actualIsCoindexed &&
393         dummy.intent != common::Intent::In) {
394       messages.Say(
395           "ALLOCATABLE %s must have INTENT(IN) to be associated with a coindexed actual argument"_err_en_US,
396           dummyName);
397     }
398     if (!actualIsCoindexed && actualLastSymbol &&
399         actualLastSymbol->Corank() != dummy.type.corank()) {
400       messages.Say(
401           "ALLOCATABLE %s has corank %d but actual argument has corank %d"_err_en_US,
402           dummyName, dummy.type.corank(), actualLastSymbol->Corank());
403     }
404   }
405 
406   // 15.5.2.7 -- dummy is POINTER
407   if (dummyIsPointer) {
408     if (dummyIsContiguous && !actualIsContiguous) {
409       messages.Say(
410           "Actual argument associated with CONTIGUOUS POINTER %s must be simply contiguous"_err_en_US,
411           dummyName);
412     }
413     if (!actualIsPointer) {
414       if (dummy.intent == common::Intent::In) {
415         semantics::CheckPointerAssignment(
416             context, parser::CharBlock{}, dummyName, dummy, actual);
417       } else {
418         messages.Say(
419             "Actual argument associated with POINTER %s must also be POINTER unless INTENT(IN)"_err_en_US,
420             dummyName);
421       }
422     }
423   }
424 
425   // 15.5.2.5 -- actual & dummy are both POINTER or both ALLOCATABLE
426   if ((actualIsPointer && dummyIsPointer) ||
427       (actualIsAllocatable && dummyIsAllocatable)) {
428     bool actualIsUnlimited{actualType.type().IsUnlimitedPolymorphic()};
429     bool dummyIsUnlimited{dummy.type.type().IsUnlimitedPolymorphic()};
430     if (actualIsUnlimited != dummyIsUnlimited) {
431       if (typesCompatible) {
432         messages.Say(
433             "If a POINTER or ALLOCATABLE dummy or actual argument is unlimited polymorphic, both must be so"_err_en_US);
434       }
435     } else if (dummyIsPolymorphic != actualIsPolymorphic) {
436       if (dummy.intent == common::Intent::In && typesCompatible) {
437         // extension: allow with warning, rule is only relevant for definables
438         messages.Say(
439             "If a POINTER or ALLOCATABLE dummy or actual argument is polymorphic, both should be so"_en_US);
440       } else {
441         messages.Say(
442             "If a POINTER or ALLOCATABLE dummy or actual argument is polymorphic, both must be so"_err_en_US);
443       }
444     } else if (!actualIsUnlimited && typesCompatible) {
445       if (!actualType.type().IsTkCompatibleWith(dummy.type.type())) {
446         if (dummy.intent == common::Intent::In) {
447           // extension: allow with warning, rule is only relevant for definables
448           messages.Say(
449               "POINTER or ALLOCATABLE dummy and actual arguments should have the same declared type and kind"_en_US);
450         } else {
451           messages.Say(
452               "POINTER or ALLOCATABLE dummy and actual arguments must have the same declared type and kind"_err_en_US);
453         }
454       }
455       if (const auto *derived{
456               evaluate::GetDerivedTypeSpec(actualType.type())}) {
457         if (!DefersSameTypeParameters(
458                 *derived, *evaluate::GetDerivedTypeSpec(dummy.type.type()))) {
459           messages.Say(
460               "Dummy and actual arguments must defer the same type parameters when POINTER or ALLOCATABLE"_err_en_US);
461         }
462       }
463     }
464   }
465 
466   // 15.5.2.8 -- coarray dummy arguments
467   if (dummy.type.corank() > 0) {
468     if (actualType.corank() == 0) {
469       messages.Say(
470           "Actual argument associated with coarray %s must be a coarray"_err_en_US,
471           dummyName);
472     }
473     if (dummyIsVolatile) {
474       if (!actualIsVolatile) {
475         messages.Say(
476             "non-VOLATILE coarray may not be associated with VOLATILE coarray %s"_err_en_US,
477             dummyName);
478       }
479     } else {
480       if (actualIsVolatile) {
481         messages.Say(
482             "VOLATILE coarray may not be associated with non-VOLATILE coarray %s"_err_en_US,
483             dummyName);
484       }
485     }
486     if (actualRank == dummy.type.Rank() && !actualIsContiguous) {
487       if (dummyIsContiguous) {
488         messages.Say(
489             "Actual argument associated with a CONTIGUOUS coarray %s must be simply contiguous"_err_en_US,
490             dummyName);
491       } else if (!dummyIsAssumedShape && !dummyIsAssumedRank) {
492         messages.Say(
493             "Actual argument associated with coarray %s (not assumed shape or rank) must be simply contiguous"_err_en_US,
494             dummyName);
495       }
496     }
497   }
498 }
499 
500 static void CheckProcedureArg(evaluate::ActualArgument &arg,
501     const characteristics::DummyProcedure &proc, const std::string &dummyName,
502     evaluate::FoldingContext &context) {
503   parser::ContextualMessages &messages{context.messages()};
504   const characteristics::Procedure &interface{proc.procedure.value()};
505   if (const auto *expr{arg.UnwrapExpr()}) {
506     bool dummyIsPointer{
507         proc.attrs.test(characteristics::DummyProcedure::Attr::Pointer)};
508     const auto *argProcDesignator{
509         std::get_if<evaluate::ProcedureDesignator>(&expr->u)};
510     const auto *argProcSymbol{
511         argProcDesignator ? argProcDesignator->GetSymbol() : nullptr};
512     if (auto argChars{characteristics::DummyArgument::FromActual(
513             "actual argument", *expr, context)}) {
514       if (!argChars->IsTypelessIntrinsicDummy()) {
515         if (auto *argProc{
516                 std::get_if<characteristics::DummyProcedure>(&argChars->u)}) {
517           characteristics::Procedure &argInterface{argProc->procedure.value()};
518           argInterface.attrs.reset(
519               characteristics::Procedure::Attr::NullPointer);
520           if (!argProcSymbol || argProcSymbol->attrs().test(Attr::INTRINSIC)) {
521             // It's ok to pass ELEMENTAL unrestricted intrinsic functions.
522             argInterface.attrs.reset(
523                 characteristics::Procedure::Attr::Elemental);
524           } else if (argInterface.attrs.test(
525                          characteristics::Procedure::Attr::Elemental)) {
526             if (argProcSymbol) { // C1533
527               evaluate::SayWithDeclaration(messages, *argProcSymbol,
528                   "Non-intrinsic ELEMENTAL procedure '%s' may not be passed as an actual argument"_err_en_US,
529                   argProcSymbol->name());
530               return; // avoid piling on with checks below
531             } else {
532               argInterface.attrs.reset(
533                   characteristics::Procedure::Attr::NullPointer);
534             }
535           }
536           if (!interface.IsPure()) {
537             // 15.5.2.9(1): if dummy is not pure, actual need not be.
538             argInterface.attrs.reset(characteristics::Procedure::Attr::Pure);
539           }
540           if (interface.HasExplicitInterface()) {
541             if (interface != argInterface) {
542               // 15.5.2.9(1): Explicit interfaces must match
543               if (argInterface.HasExplicitInterface()) {
544                 messages.Say(
545                     "Actual procedure argument has interface incompatible with %s"_err_en_US,
546                     dummyName);
547                 return;
548               } else {
549                 messages.Say(
550                     "Actual procedure argument has an implicit interface "
551                     "which is not known to be compatible with %s which has an "
552                     "explicit interface"_err_en_US,
553                     dummyName);
554                 return;
555               }
556             }
557           } else { // 15.5.2.9(2,3)
558             if (interface.IsSubroutine() && argInterface.IsFunction()) {
559               messages.Say(
560                   "Actual argument associated with procedure %s is a function but must be a subroutine"_err_en_US,
561                   dummyName);
562             } else if (interface.IsFunction()) {
563               if (argInterface.IsFunction()) {
564                 if (interface.functionResult != argInterface.functionResult) {
565                   messages.Say(
566                       "Actual argument function associated with procedure %s has incompatible result type"_err_en_US,
567                       dummyName);
568                 }
569               } else if (argInterface.IsSubroutine()) {
570                 messages.Say(
571                     "Actual argument associated with procedure %s is a subroutine but must be a function"_err_en_US,
572                     dummyName);
573               }
574             }
575           }
576         } else {
577           messages.Say(
578               "Actual argument associated with procedure %s is not a procedure"_err_en_US,
579               dummyName);
580         }
581       } else if (!(dummyIsPointer && IsNullPointer(*expr))) {
582         messages.Say(
583             "Actual argument associated with procedure %s is not a procedure"_err_en_US,
584             dummyName);
585       }
586     }
587     if (interface.HasExplicitInterface()) {
588       if (dummyIsPointer) {
589         // 15.5.2.9(5) -- dummy procedure POINTER
590         // Interface compatibility has already been checked above by comparison.
591         if (proc.intent != common::Intent::In && !IsVariable(*expr)) {
592           messages.Say(
593               "Actual argument associated with procedure pointer %s must be a POINTER unless INTENT(IN)"_err_en_US,
594               dummyName);
595         }
596       } else { // 15.5.2.9(4) -- dummy procedure is not POINTER
597         if (!argProcDesignator) {
598           messages.Say(
599               "Actual argument associated with non-POINTER procedure %s must be a procedure (and not a procedure pointer)"_err_en_US,
600               dummyName);
601         }
602       }
603     }
604   } else {
605     messages.Say(
606         "Assumed-type argument may not be forwarded as procedure %s"_err_en_US,
607         dummyName);
608   }
609 }
610 
611 static void CheckExplicitInterfaceArg(evaluate::ActualArgument &arg,
612     const characteristics::DummyArgument &dummy,
613     const characteristics::Procedure &proc, evaluate::FoldingContext &context,
614     const Scope *scope, const evaluate::SpecificIntrinsic *intrinsic) {
615   auto &messages{context.messages()};
616   std::string dummyName{"dummy argument"};
617   if (!dummy.name.empty()) {
618     dummyName += " '"s + parser::ToLowerCaseLetters(dummy.name) + "='";
619   }
620   std::visit(
621       common::visitors{
622           [&](const characteristics::DummyDataObject &object) {
623             if (auto *expr{arg.UnwrapExpr()}) {
624               if (auto type{characteristics::TypeAndShape::Characterize(
625                       *expr, context)}) {
626                 arg.set_dummyIntent(object.intent);
627                 bool isElemental{object.type.Rank() == 0 && proc.IsElemental()};
628                 CheckExplicitDataArg(object, dummyName, *expr, *type,
629                     isElemental, context, scope, intrinsic);
630               } else if (object.type.type().IsTypelessIntrinsicArgument() &&
631                   std::holds_alternative<evaluate::BOZLiteralConstant>(
632                       expr->u)) {
633                 // ok
634               } else if (object.type.type().IsTypelessIntrinsicArgument() &&
635                   evaluate::IsNullPointer(*expr)) {
636                 // ok, ASSOCIATED(NULL())
637               } else if (object.attrs.test(
638                              characteristics::DummyDataObject::Attr::Pointer) &&
639                   evaluate::IsNullPointer(*expr)) {
640                 // ok, FOO(NULL())
641               } else {
642                 messages.Say(
643                     "Actual argument '%s' associated with %s is not a variable or typed expression"_err_en_US,
644                     expr->AsFortran(), dummyName);
645               }
646             } else {
647               const Symbol &assumed{DEREF(arg.GetAssumedTypeDummy())};
648               if (!object.type.type().IsAssumedType()) {
649                 messages.Say(
650                     "Assumed-type '%s' may be associated only with an assumed-type %s"_err_en_US,
651                     assumed.name(), dummyName);
652               } else if (const auto *details{
653                              assumed.detailsIf<ObjectEntityDetails>()}) {
654                 if (!(details->IsAssumedShape() || details->IsAssumedRank())) {
655                   messages.Say( // C711
656                       "Assumed-type '%s' must be either assumed shape or assumed rank to be associated with assumed-type %s"_err_en_US,
657                       assumed.name(), dummyName);
658                 }
659               }
660             }
661           },
662           [&](const characteristics::DummyProcedure &proc) {
663             CheckProcedureArg(arg, proc, dummyName, context);
664           },
665           [&](const characteristics::AlternateReturn &) {
666             // All semantic checking is done elsewhere
667           },
668       },
669       dummy.u);
670 }
671 
672 static void RearrangeArguments(const characteristics::Procedure &proc,
673     evaluate::ActualArguments &actuals, parser::ContextualMessages &messages) {
674   CHECK(proc.HasExplicitInterface());
675   if (actuals.size() < proc.dummyArguments.size()) {
676     actuals.resize(proc.dummyArguments.size());
677   } else if (actuals.size() > proc.dummyArguments.size()) {
678     messages.Say(
679         "Too many actual arguments (%zd) passed to procedure that expects only %zd"_err_en_US,
680         actuals.size(), proc.dummyArguments.size());
681   }
682   std::map<std::string, evaluate::ActualArgument> kwArgs;
683   for (auto &x : actuals) {
684     if (x && x->keyword()) {
685       auto emplaced{
686           kwArgs.try_emplace(x->keyword()->ToString(), std::move(*x))};
687       if (!emplaced.second) {
688         messages.Say(*x->keyword(),
689             "Argument keyword '%s=' appears on more than one effective argument in this procedure reference"_err_en_US,
690             *x->keyword());
691       }
692       x.reset();
693     }
694   }
695   if (!kwArgs.empty()) {
696     int index{0};
697     for (const auto &dummy : proc.dummyArguments) {
698       if (!dummy.name.empty()) {
699         auto iter{kwArgs.find(dummy.name)};
700         if (iter != kwArgs.end()) {
701           evaluate::ActualArgument &x{iter->second};
702           if (actuals[index]) {
703             messages.Say(*x.keyword(),
704                 "Keyword argument '%s=' has already been specified positionally (#%d) in this procedure reference"_err_en_US,
705                 *x.keyword(), index + 1);
706           } else {
707             actuals[index] = std::move(x);
708           }
709           kwArgs.erase(iter);
710         }
711       }
712       ++index;
713     }
714     for (auto &bad : kwArgs) {
715       evaluate::ActualArgument &x{bad.second};
716       messages.Say(*x.keyword(),
717           "Argument keyword '%s=' is not recognized for this procedure reference"_err_en_US,
718           *x.keyword());
719     }
720   }
721 }
722 
723 static parser::Messages CheckExplicitInterface(
724     const characteristics::Procedure &proc, evaluate::ActualArguments &actuals,
725     const evaluate::FoldingContext &context, const Scope *scope,
726     const evaluate::SpecificIntrinsic *intrinsic) {
727   parser::Messages buffer;
728   parser::ContextualMessages messages{context.messages().at(), &buffer};
729   RearrangeArguments(proc, actuals, messages);
730   if (buffer.empty()) {
731     int index{0};
732     evaluate::FoldingContext localContext{context, messages};
733     for (auto &actual : actuals) {
734       const auto &dummy{proc.dummyArguments.at(index++)};
735       if (actual) {
736         CheckExplicitInterfaceArg(
737             *actual, dummy, proc, localContext, scope, intrinsic);
738       } else if (!dummy.IsOptional()) {
739         if (dummy.name.empty()) {
740           messages.Say(
741               "Dummy argument #%d is not OPTIONAL and is not associated with "
742               "an actual argument in this procedure reference"_err_en_US,
743               index);
744         } else {
745           messages.Say("Dummy argument '%s=' (#%d) is not OPTIONAL and is not "
746                        "associated with an actual argument in this procedure "
747                        "reference"_err_en_US,
748               dummy.name, index);
749         }
750       }
751     }
752   }
753   return buffer;
754 }
755 
756 parser::Messages CheckExplicitInterface(const characteristics::Procedure &proc,
757     evaluate::ActualArguments &actuals, const evaluate::FoldingContext &context,
758     const Scope &scope, const evaluate::SpecificIntrinsic *intrinsic) {
759   return CheckExplicitInterface(proc, actuals, context, &scope, intrinsic);
760 }
761 
762 bool CheckInterfaceForGeneric(const characteristics::Procedure &proc,
763     evaluate::ActualArguments &actuals,
764     const evaluate::FoldingContext &context) {
765   return CheckExplicitInterface(proc, actuals, context, nullptr, nullptr)
766       .empty();
767 }
768 
769 void CheckArguments(const characteristics::Procedure &proc,
770     evaluate::ActualArguments &actuals, evaluate::FoldingContext &context,
771     const Scope &scope, bool treatingExternalAsImplicit,
772     const evaluate::SpecificIntrinsic *intrinsic) {
773   bool explicitInterface{proc.HasExplicitInterface()};
774   if (explicitInterface) {
775     auto buffer{
776         CheckExplicitInterface(proc, actuals, context, scope, intrinsic)};
777     if (treatingExternalAsImplicit && !buffer.empty()) {
778       if (auto *msg{context.messages().Say(
779               "Warning: if the procedure's interface were explicit, this reference would be in error:"_en_US)}) {
780         buffer.AttachTo(*msg);
781       }
782     }
783     if (auto *msgs{context.messages().messages()}) {
784       msgs->Merge(std::move(buffer));
785     }
786   }
787   if (!explicitInterface || treatingExternalAsImplicit) {
788     for (auto &actual : actuals) {
789       if (actual) {
790         CheckImplicitInterfaceArg(*actual, context.messages());
791       }
792     }
793   }
794 }
795 } // namespace Fortran::semantics
796