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   auto restorer{
30       messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
31   if (auto kw{arg.keyword()}) {
32     messages.Say(*kw,
33         "Keyword '%s=' may not appear in a reference to a procedure with an implicit interface"_err_en_US,
34         *kw);
35   }
36   if (auto type{arg.GetType()}) {
37     if (type->IsAssumedType()) {
38       messages.Say(
39           "Assumed type argument requires an explicit interface"_err_en_US);
40     } else if (type->IsPolymorphic()) {
41       messages.Say(
42           "Polymorphic argument requires an explicit interface"_err_en_US);
43     } else if (const DerivedTypeSpec * derived{GetDerivedTypeSpec(type)}) {
44       if (!derived->parameters().empty()) {
45         messages.Say(
46             "Parameterized derived type argument requires an explicit interface"_err_en_US);
47       }
48     }
49   }
50   if (const auto *expr{arg.UnwrapExpr()}) {
51     if (IsBOZLiteral(*expr)) {
52       messages.Say("BOZ argument requires an explicit interface"_err_en_US);
53     } else if (evaluate::IsNullPointer(*expr)) {
54       messages.Say(
55           "Null pointer argument requires an explicit interface"_err_en_US);
56     } else if (auto named{evaluate::ExtractNamedEntity(*expr)}) {
57       const Symbol &symbol{named->GetLastSymbol()};
58       if (symbol.Corank() > 0) {
59         messages.Say(
60             "Coarray argument requires an explicit interface"_err_en_US);
61       }
62       if (const auto *details{symbol.detailsIf<ObjectEntityDetails>()}) {
63         if (details->IsAssumedRank()) {
64           messages.Say(
65               "Assumed rank argument requires an explicit interface"_err_en_US);
66         }
67       }
68       if (symbol.attrs().test(Attr::ASYNCHRONOUS)) {
69         messages.Say(
70             "ASYNCHRONOUS argument requires an explicit interface"_err_en_US);
71       }
72       if (symbol.attrs().test(Attr::VOLATILE)) {
73         messages.Say(
74             "VOLATILE argument requires an explicit interface"_err_en_US);
75       }
76     }
77   }
78 }
79 
80 // When scalar CHARACTER actual arguments are known to be short,
81 // we extend them on the right with spaces and a warning.
82 static void PadShortCharacterActual(evaluate::Expr<evaluate::SomeType> &actual,
83     const characteristics::TypeAndShape &dummyType,
84     characteristics::TypeAndShape &actualType,
85     evaluate::FoldingContext &context, parser::ContextualMessages &messages) {
86   if (dummyType.type().category() == TypeCategory::Character &&
87       actualType.type().category() == TypeCategory::Character &&
88       dummyType.type().kind() == actualType.type().kind() &&
89       GetRank(actualType.shape()) == 0) {
90     if (dummyType.LEN() && actualType.LEN()) {
91       auto dummyLength{ToInt64(Fold(context, common::Clone(*dummyType.LEN())))};
92       auto actualLength{
93           ToInt64(Fold(context, common::Clone(*actualType.LEN())))};
94       if (dummyLength && actualLength && *actualLength < *dummyLength) {
95         messages.Say(
96             "Actual length '%jd' is less than expected length '%jd'"_en_US,
97             *actualLength, *dummyLength);
98         auto converted{ConvertToType(dummyType.type(), std::move(actual))};
99         CHECK(converted);
100         actual = std::move(*converted);
101         actualType.set_LEN(SubscriptIntExpr{*dummyLength});
102       }
103     }
104   }
105 }
106 
107 // Automatic conversion of different-kind INTEGER scalar actual
108 // argument expressions (not variables) to INTEGER scalar dummies.
109 // We return nonstandard INTEGER(8) results from intrinsic functions
110 // like SIZE() by default in order to facilitate the use of large
111 // arrays.  Emit a warning when downconverting.
112 static void ConvertIntegerActual(evaluate::Expr<evaluate::SomeType> &actual,
113     const characteristics::TypeAndShape &dummyType,
114     characteristics::TypeAndShape &actualType,
115     parser::ContextualMessages &messages) {
116   if (dummyType.type().category() == TypeCategory::Integer &&
117       actualType.type().category() == TypeCategory::Integer &&
118       dummyType.type().kind() != actualType.type().kind() &&
119       GetRank(dummyType.shape()) == 0 && GetRank(actualType.shape()) == 0 &&
120       !evaluate::IsVariable(actual)) {
121     auto converted{
122         evaluate::ConvertToType(dummyType.type(), std::move(actual))};
123     CHECK(converted);
124     actual = std::move(*converted);
125     if (dummyType.type().kind() < actualType.type().kind()) {
126       messages.Say(
127           "Actual argument scalar expression of type INTEGER(%d) was converted to smaller dummy argument type INTEGER(%d)"_en_US,
128           actualType.type().kind(), dummyType.type().kind());
129     }
130     actualType = dummyType;
131   }
132 }
133 
134 static bool DefersSameTypeParameters(
135     const DerivedTypeSpec &actual, const DerivedTypeSpec &dummy) {
136   for (const auto &pair : actual.parameters()) {
137     const ParamValue &actualValue{pair.second};
138     const ParamValue *dummyValue{dummy.FindParameter(pair.first)};
139     if (!dummyValue || (actualValue.isDeferred() != dummyValue->isDeferred())) {
140       return false;
141     }
142   }
143   return true;
144 }
145 
146 static void CheckExplicitDataArg(const characteristics::DummyDataObject &dummy,
147     const std::string &dummyName, evaluate::Expr<evaluate::SomeType> &actual,
148     characteristics::TypeAndShape &actualType, bool isElemental,
149     evaluate::FoldingContext &context, const Scope *scope,
150     const evaluate::SpecificIntrinsic *intrinsic,
151     bool allowIntegerConversions) {
152 
153   // Basic type & rank checking
154   parser::ContextualMessages &messages{context.messages()};
155   PadShortCharacterActual(actual, dummy.type, actualType, context, messages);
156   if (allowIntegerConversions) {
157     ConvertIntegerActual(actual, dummy.type, actualType, messages);
158   }
159   bool typesCompatible{dummy.type.type().IsTkCompatibleWith(actualType.type())};
160   if (typesCompatible) {
161     if (isElemental) {
162     } else if (dummy.type.attrs().test(
163                    characteristics::TypeAndShape::Attr::AssumedRank)) {
164     } else if (!dummy.type.attrs().test(
165                    characteristics::TypeAndShape::Attr::AssumedShape) &&
166         !dummy.type.attrs().test(
167             characteristics::TypeAndShape::Attr::DeferredShape) &&
168         (actualType.Rank() > 0 || IsArrayElement(actual))) {
169       // Sequence association (15.5.2.11) applies -- rank need not match
170       // if the actual argument is an array or array element designator,
171       // and the dummy is not assumed-shape or an INTENT(IN) pointer
172       // that's standing in for an assumed-shape dummy.
173     } else {
174       // Let CheckConformance accept scalars; storage association
175       // cases are checked here below.
176       CheckConformance(messages, dummy.type.shape(), actualType.shape(),
177           evaluate::CheckConformanceFlags::EitherScalarExpandable,
178           "dummy argument", "actual argument");
179     }
180   } else {
181     const auto &len{actualType.LEN()};
182     messages.Say(
183         "Actual argument type '%s' is not compatible with dummy argument type '%s'"_err_en_US,
184         actualType.type().AsFortran(len ? len->AsFortran() : ""),
185         dummy.type.type().AsFortran());
186   }
187 
188   bool actualIsPolymorphic{actualType.type().IsPolymorphic()};
189   bool dummyIsPolymorphic{dummy.type.type().IsPolymorphic()};
190   bool actualIsCoindexed{ExtractCoarrayRef(actual).has_value()};
191   bool actualIsAssumedSize{actualType.attrs().test(
192       characteristics::TypeAndShape::Attr::AssumedSize)};
193   bool dummyIsAssumedSize{dummy.type.attrs().test(
194       characteristics::TypeAndShape::Attr::AssumedSize)};
195   bool dummyIsAsynchronous{
196       dummy.attrs.test(characteristics::DummyDataObject::Attr::Asynchronous)};
197   bool dummyIsVolatile{
198       dummy.attrs.test(characteristics::DummyDataObject::Attr::Volatile)};
199   bool dummyIsValue{
200       dummy.attrs.test(characteristics::DummyDataObject::Attr::Value)};
201 
202   if (actualIsPolymorphic && dummyIsPolymorphic &&
203       actualIsCoindexed) { // 15.5.2.4(2)
204     messages.Say(
205         "Coindexed polymorphic object may not be associated with a polymorphic %s"_err_en_US,
206         dummyName);
207   }
208   if (actualIsPolymorphic && !dummyIsPolymorphic &&
209       actualIsAssumedSize) { // 15.5.2.4(2)
210     messages.Say(
211         "Assumed-size polymorphic array may not be associated with a monomorphic %s"_err_en_US,
212         dummyName);
213   }
214 
215   // Derived type actual argument checks
216   const Symbol *actualFirstSymbol{evaluate::GetFirstSymbol(actual)};
217   bool actualIsAsynchronous{
218       actualFirstSymbol && actualFirstSymbol->attrs().test(Attr::ASYNCHRONOUS)};
219   bool actualIsVolatile{
220       actualFirstSymbol && actualFirstSymbol->attrs().test(Attr::VOLATILE)};
221   if (const auto *derived{evaluate::GetDerivedTypeSpec(actualType.type())}) {
222     if (dummy.type.type().IsAssumedType()) {
223       if (!derived->parameters().empty()) { // 15.5.2.4(2)
224         messages.Say(
225             "Actual argument associated with TYPE(*) %s may not have a parameterized derived type"_err_en_US,
226             dummyName);
227       }
228       if (const Symbol *
229           tbp{FindImmediateComponent(*derived, [](const Symbol &symbol) {
230             return symbol.has<ProcBindingDetails>();
231           })}) { // 15.5.2.4(2)
232         evaluate::SayWithDeclaration(messages, *tbp,
233             "Actual argument associated with TYPE(*) %s may not have type-bound procedure '%s'"_err_en_US,
234             dummyName, tbp->name());
235       }
236       const auto &finals{
237           derived->typeSymbol().get<DerivedTypeDetails>().finals()};
238       if (!finals.empty()) { // 15.5.2.4(2)
239         if (auto *msg{messages.Say(
240                 "Actual argument associated with TYPE(*) %s may not have derived type '%s' with FINAL subroutine '%s'"_err_en_US,
241                 dummyName, derived->typeSymbol().name(),
242                 finals.begin()->first)}) {
243           msg->Attach(finals.begin()->first,
244               "FINAL subroutine '%s' in derived type '%s'"_en_US,
245               finals.begin()->first, derived->typeSymbol().name());
246         }
247       }
248     }
249     if (actualIsCoindexed) {
250       if (dummy.intent != common::Intent::In && !dummyIsValue) {
251         if (auto bad{
252                 FindAllocatableUltimateComponent(*derived)}) { // 15.5.2.4(6)
253           evaluate::SayWithDeclaration(messages, *bad,
254               "Coindexed actual argument with ALLOCATABLE ultimate component '%s' must be associated with a %s with VALUE or INTENT(IN) attributes"_err_en_US,
255               bad.BuildResultDesignatorName(), dummyName);
256         }
257       }
258       if (auto coarrayRef{evaluate::ExtractCoarrayRef(actual)}) { // C1537
259         const Symbol &coarray{coarrayRef->GetLastSymbol()};
260         if (const DeclTypeSpec * type{coarray.GetType()}) {
261           if (const DerivedTypeSpec * derived{type->AsDerived()}) {
262             if (auto bad{semantics::FindPointerUltimateComponent(*derived)}) {
263               evaluate::SayWithDeclaration(messages, coarray,
264                   "Coindexed object '%s' with POINTER ultimate component '%s' cannot be associated with %s"_err_en_US,
265                   coarray.name(), bad.BuildResultDesignatorName(), dummyName);
266             }
267           }
268         }
269       }
270     }
271     if (actualIsVolatile != dummyIsVolatile) { // 15.5.2.4(22)
272       if (auto bad{semantics::FindCoarrayUltimateComponent(*derived)}) {
273         evaluate::SayWithDeclaration(messages, *bad,
274             "VOLATILE attribute must match for %s when actual argument has a coarray ultimate component '%s'"_err_en_US,
275             dummyName, bad.BuildResultDesignatorName());
276       }
277     }
278   }
279 
280   // Rank and shape checks
281   const auto *actualLastSymbol{evaluate::GetLastSymbol(actual)};
282   if (actualLastSymbol) {
283     actualLastSymbol = &ResolveAssociations(*actualLastSymbol);
284   }
285   const ObjectEntityDetails *actualLastObject{actualLastSymbol
286           ? actualLastSymbol->detailsIf<ObjectEntityDetails>()
287           : nullptr};
288   int actualRank{evaluate::GetRank(actualType.shape())};
289   bool actualIsPointer{evaluate::IsObjectPointer(actual, context)};
290   bool dummyIsAssumedRank{dummy.type.attrs().test(
291       characteristics::TypeAndShape::Attr::AssumedRank)};
292   if (dummy.type.attrs().test(
293           characteristics::TypeAndShape::Attr::AssumedShape)) {
294     // 15.5.2.4(16)
295     if (actualRank == 0) {
296       messages.Say(
297           "Scalar actual argument may not be associated with assumed-shape %s"_err_en_US,
298           dummyName);
299     }
300     if (actualIsAssumedSize && actualLastSymbol) {
301       evaluate::SayWithDeclaration(messages, *actualLastSymbol,
302           "Assumed-size array may not be associated with assumed-shape %s"_err_en_US,
303           dummyName);
304     }
305   } else if (actualRank == 0 && dummy.type.Rank() > 0) {
306     // Actual is scalar, dummy is an array.  15.5.2.4(14), 15.5.2.11
307     if (actualIsCoindexed) {
308       messages.Say(
309           "Coindexed scalar actual argument must be associated with a scalar %s"_err_en_US,
310           dummyName);
311     }
312     if (!IsArrayElement(actual) &&
313         !(actualType.type().category() == TypeCategory::Character &&
314             actualType.type().kind() == 1) &&
315         !(dummy.type.type().IsAssumedType() && dummyIsAssumedSize) &&
316         !dummyIsAssumedRank) {
317       messages.Say(
318           "Whole scalar actual argument may not be associated with a %s array"_err_en_US,
319           dummyName);
320     }
321     if (actualIsPolymorphic) {
322       messages.Say(
323           "Polymorphic scalar may not be associated with a %s array"_err_en_US,
324           dummyName);
325     }
326     if (actualIsPointer) {
327       messages.Say(
328           "Scalar POINTER target may not be associated with a %s array"_err_en_US,
329           dummyName);
330     }
331     if (actualLastSymbol && IsAssumedShape(*actualLastSymbol)) {
332       messages.Say(
333           "Element of assumed-shape array may not be associated with a %s array"_err_en_US,
334           dummyName);
335     }
336   }
337   if (actualLastObject && actualLastObject->IsCoarray() &&
338       IsAllocatable(*actualLastSymbol) && dummy.intent == common::Intent::Out &&
339       !(intrinsic &&
340           evaluate::AcceptsIntentOutAllocatableCoarray(
341               intrinsic->name))) { // C846
342     messages.Say(
343         "ALLOCATABLE coarray '%s' may not be associated with INTENT(OUT) %s"_err_en_US,
344         actualLastSymbol->name(), dummyName);
345   }
346 
347   // Definability
348   const char *reason{nullptr};
349   if (dummy.intent == common::Intent::Out) {
350     reason = "INTENT(OUT)";
351   } else if (dummy.intent == common::Intent::InOut) {
352     reason = "INTENT(IN OUT)";
353   } else if (dummyIsAsynchronous) {
354     reason = "ASYNCHRONOUS";
355   } else if (dummyIsVolatile) {
356     reason = "VOLATILE";
357   }
358   if (reason && scope) {
359     bool vectorSubscriptIsOk{isElemental || dummyIsValue}; // 15.5.2.4(21)
360     if (auto why{WhyNotModifiable(
361             messages.at(), actual, *scope, vectorSubscriptIsOk)}) {
362       if (auto *msg{messages.Say(
363               "Actual argument associated with %s %s must be definable"_err_en_US, // C1158
364               reason, dummyName)}) {
365         msg->Attach(*why);
366       }
367     }
368   }
369 
370   // Cases when temporaries might be needed but must not be permitted.
371   bool actualIsContiguous{IsSimplyContiguous(actual, context)};
372   bool dummyIsAssumedShape{dummy.type.attrs().test(
373       characteristics::TypeAndShape::Attr::AssumedShape)};
374   bool dummyIsPointer{
375       dummy.attrs.test(characteristics::DummyDataObject::Attr::Pointer)};
376   bool dummyIsContiguous{
377       dummy.attrs.test(characteristics::DummyDataObject::Attr::Contiguous)};
378   if ((actualIsAsynchronous || actualIsVolatile) &&
379       (dummyIsAsynchronous || dummyIsVolatile) && !dummyIsValue) {
380     if (actualIsCoindexed) { // C1538
381       messages.Say(
382           "Coindexed ASYNCHRONOUS or VOLATILE actual argument may not be associated with %s with ASYNCHRONOUS or VOLATILE attributes unless VALUE"_err_en_US,
383           dummyName);
384     }
385     if (actualRank > 0 && !actualIsContiguous) {
386       if (dummyIsContiguous ||
387           !(dummyIsAssumedShape || dummyIsAssumedRank ||
388               (actualIsPointer && dummyIsPointer))) { // C1539 & C1540
389         messages.Say(
390             "ASYNCHRONOUS or VOLATILE actual argument that is not simply contiguous may not be associated with a contiguous %s"_err_en_US,
391             dummyName);
392       }
393     }
394   }
395 
396   // 15.5.2.6 -- dummy is ALLOCATABLE
397   bool dummyIsAllocatable{
398       dummy.attrs.test(characteristics::DummyDataObject::Attr::Allocatable)};
399   bool actualIsAllocatable{
400       actualLastSymbol && IsAllocatable(*actualLastSymbol)};
401   if (dummyIsAllocatable) {
402     if (!actualIsAllocatable) {
403       messages.Say(
404           "ALLOCATABLE %s must be associated with an ALLOCATABLE actual argument"_err_en_US,
405           dummyName);
406     }
407     if (actualIsAllocatable && actualIsCoindexed &&
408         dummy.intent != common::Intent::In) {
409       messages.Say(
410           "ALLOCATABLE %s must have INTENT(IN) to be associated with a coindexed actual argument"_err_en_US,
411           dummyName);
412     }
413     if (!actualIsCoindexed && actualLastSymbol &&
414         actualLastSymbol->Corank() != dummy.type.corank()) {
415       messages.Say(
416           "ALLOCATABLE %s has corank %d but actual argument has corank %d"_err_en_US,
417           dummyName, dummy.type.corank(), actualLastSymbol->Corank());
418     }
419   }
420 
421   // 15.5.2.7 -- dummy is POINTER
422   if (dummyIsPointer) {
423     if (dummyIsContiguous && !actualIsContiguous) {
424       messages.Say(
425           "Actual argument associated with CONTIGUOUS POINTER %s must be simply contiguous"_err_en_US,
426           dummyName);
427     }
428     if (!actualIsPointer) {
429       if (dummy.intent == common::Intent::In) {
430         semantics::CheckPointerAssignment(
431             context, parser::CharBlock{}, dummyName, dummy, actual);
432       } else {
433         messages.Say(
434             "Actual argument associated with POINTER %s must also be POINTER unless INTENT(IN)"_err_en_US,
435             dummyName);
436       }
437     }
438   }
439 
440   // 15.5.2.5 -- actual & dummy are both POINTER or both ALLOCATABLE
441   if ((actualIsPointer && dummyIsPointer) ||
442       (actualIsAllocatable && dummyIsAllocatable)) {
443     bool actualIsUnlimited{actualType.type().IsUnlimitedPolymorphic()};
444     bool dummyIsUnlimited{dummy.type.type().IsUnlimitedPolymorphic()};
445     if (actualIsUnlimited != dummyIsUnlimited) {
446       if (typesCompatible) {
447         messages.Say(
448             "If a POINTER or ALLOCATABLE dummy or actual argument is unlimited polymorphic, both must be so"_err_en_US);
449       }
450     } else if (dummyIsPolymorphic != actualIsPolymorphic) {
451       if (dummy.intent == common::Intent::In && typesCompatible) {
452         // extension: allow with warning, rule is only relevant for definables
453         messages.Say(
454             "If a POINTER or ALLOCATABLE dummy or actual argument is polymorphic, both should be so"_en_US);
455       } else {
456         messages.Say(
457             "If a POINTER or ALLOCATABLE dummy or actual argument is polymorphic, both must be so"_err_en_US);
458       }
459     } else if (!actualIsUnlimited && typesCompatible) {
460       if (!actualType.type().IsTkCompatibleWith(dummy.type.type())) {
461         if (dummy.intent == common::Intent::In) {
462           // extension: allow with warning, rule is only relevant for definables
463           messages.Say(
464               "POINTER or ALLOCATABLE dummy and actual arguments should have the same declared type and kind"_en_US);
465         } else {
466           messages.Say(
467               "POINTER or ALLOCATABLE dummy and actual arguments must have the same declared type and kind"_err_en_US);
468         }
469       }
470       if (const auto *derived{
471               evaluate::GetDerivedTypeSpec(actualType.type())}) {
472         if (!DefersSameTypeParameters(
473                 *derived, *evaluate::GetDerivedTypeSpec(dummy.type.type()))) {
474           messages.Say(
475               "Dummy and actual arguments must defer the same type parameters when POINTER or ALLOCATABLE"_err_en_US);
476         }
477       }
478     }
479   }
480 
481   // 15.5.2.8 -- coarray dummy arguments
482   if (dummy.type.corank() > 0) {
483     if (actualType.corank() == 0) {
484       messages.Say(
485           "Actual argument associated with coarray %s must be a coarray"_err_en_US,
486           dummyName);
487     }
488     if (dummyIsVolatile) {
489       if (!actualIsVolatile) {
490         messages.Say(
491             "non-VOLATILE coarray may not be associated with VOLATILE coarray %s"_err_en_US,
492             dummyName);
493       }
494     } else {
495       if (actualIsVolatile) {
496         messages.Say(
497             "VOLATILE coarray may not be associated with non-VOLATILE coarray %s"_err_en_US,
498             dummyName);
499       }
500     }
501     if (actualRank == dummy.type.Rank() && !actualIsContiguous) {
502       if (dummyIsContiguous) {
503         messages.Say(
504             "Actual argument associated with a CONTIGUOUS coarray %s must be simply contiguous"_err_en_US,
505             dummyName);
506       } else if (!dummyIsAssumedShape && !dummyIsAssumedRank) {
507         messages.Say(
508             "Actual argument associated with coarray %s (not assumed shape or rank) must be simply contiguous"_err_en_US,
509             dummyName);
510       }
511     }
512   }
513 
514   // NULL(MOLD=) checking for non-intrinsic procedures
515   bool dummyIsOptional{
516       dummy.attrs.test(characteristics::DummyDataObject::Attr::Optional)};
517   bool actualIsNull{evaluate::IsNullPointer(actual)};
518   if (!intrinsic && !dummyIsPointer && !dummyIsOptional && actualIsNull) {
519     messages.Say(
520         "Actual argument associated with %s may not be null pointer %s"_err_en_US,
521         dummyName, actual.AsFortran());
522   }
523 }
524 
525 static void CheckProcedureArg(evaluate::ActualArgument &arg,
526     const characteristics::Procedure &proc,
527     const characteristics::DummyProcedure &dummy, const std::string &dummyName,
528     evaluate::FoldingContext &context) {
529   parser::ContextualMessages &messages{context.messages()};
530   auto restorer{
531       messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
532   const characteristics::Procedure &interface { dummy.procedure.value() };
533   if (const auto *expr{arg.UnwrapExpr()}) {
534     bool dummyIsPointer{
535         dummy.attrs.test(characteristics::DummyProcedure::Attr::Pointer)};
536     const auto *argProcDesignator{
537         std::get_if<evaluate::ProcedureDesignator>(&expr->u)};
538     const auto *argProcSymbol{
539         argProcDesignator ? argProcDesignator->GetSymbol() : nullptr};
540     if (auto argChars{characteristics::DummyArgument::FromActual(
541             "actual argument", *expr, context)}) {
542       if (!argChars->IsTypelessIntrinsicDummy()) {
543         if (auto *argProc{
544                 std::get_if<characteristics::DummyProcedure>(&argChars->u)}) {
545           characteristics::Procedure &argInterface{argProc->procedure.value()};
546           argInterface.attrs.reset(
547               characteristics::Procedure::Attr::NullPointer);
548           if (!argProcSymbol || argProcSymbol->attrs().test(Attr::INTRINSIC)) {
549             // It's ok to pass ELEMENTAL unrestricted intrinsic functions.
550             argInterface.attrs.reset(
551                 characteristics::Procedure::Attr::Elemental);
552           } else if (argInterface.attrs.test(
553                          characteristics::Procedure::Attr::Elemental)) {
554             if (argProcSymbol) { // C1533
555               evaluate::SayWithDeclaration(messages, *argProcSymbol,
556                   "Non-intrinsic ELEMENTAL procedure '%s' may not be passed as an actual argument"_err_en_US,
557                   argProcSymbol->name());
558               return; // avoid piling on with checks below
559             } else {
560               argInterface.attrs.reset(
561                   characteristics::Procedure::Attr::NullPointer);
562             }
563           }
564           if (interface.HasExplicitInterface()) {
565             if (!interface.IsCompatibleWith(argInterface)) {
566               // 15.5.2.9(1): Explicit interfaces must match
567               if (argInterface.HasExplicitInterface()) {
568                 messages.Say(
569                     "Actual procedure argument has interface incompatible with %s"_err_en_US,
570                     dummyName);
571                 return;
572               } else if (proc.IsPure()) {
573                 messages.Say(
574                     "Actual procedure argument for %s of a PURE procedure must have an explicit interface"_err_en_US,
575                     dummyName);
576               } else {
577                 messages.Say(
578                     "Actual procedure argument has an implicit interface "
579                     "which is not known to be compatible with %s which has an "
580                     "explicit interface"_en_US,
581                     dummyName);
582               }
583             }
584           } else { // 15.5.2.9(2,3)
585             if (interface.IsSubroutine() && argInterface.IsFunction()) {
586               messages.Say(
587                   "Actual argument associated with procedure %s is a function but must be a subroutine"_err_en_US,
588                   dummyName);
589             } else if (interface.IsFunction()) {
590               if (argInterface.IsFunction()) {
591                 if (!interface.functionResult->IsCompatibleWith(
592                         *argInterface.functionResult)) {
593                   messages.Say(
594                       "Actual argument function associated with procedure %s has incompatible result type"_err_en_US,
595                       dummyName);
596                 }
597               } else if (argInterface.IsSubroutine()) {
598                 messages.Say(
599                     "Actual argument associated with procedure %s is a subroutine but must be a function"_err_en_US,
600                     dummyName);
601               }
602             }
603           }
604         } else {
605           messages.Say(
606               "Actual argument associated with procedure %s is not a procedure"_err_en_US,
607               dummyName);
608         }
609       } else if (IsNullPointer(*expr)) {
610         if (!dummyIsPointer) {
611           messages.Say(
612               "Actual argument associated with procedure %s is a null pointer"_err_en_US,
613               dummyName);
614         }
615       } else {
616         messages.Say(
617             "Actual argument associated with procedure %s is typeless"_err_en_US,
618             dummyName);
619       }
620     }
621     if (interface.HasExplicitInterface() && dummyIsPointer &&
622         dummy.intent != common::Intent::In) {
623       const Symbol *last{GetLastSymbol(*expr)};
624       if (!(last && IsProcedurePointer(*last))) {
625         // 15.5.2.9(5) -- dummy procedure POINTER
626         // Interface compatibility has already been checked above
627         messages.Say(
628             "Actual argument associated with procedure pointer %s must be a POINTER unless INTENT(IN)"_err_en_US,
629             dummyName);
630       }
631     }
632   } else {
633     messages.Say(
634         "Assumed-type argument may not be forwarded as procedure %s"_err_en_US,
635         dummyName);
636   }
637 }
638 
639 // Allow BOZ literal actual arguments when they can be converted to a known
640 // dummy argument type
641 static void ConvertBOZLiteralArg(
642     evaluate::ActualArgument &arg, const evaluate::DynamicType &type) {
643   if (auto *expr{arg.UnwrapExpr()}) {
644     if (IsBOZLiteral(*expr)) {
645       if (auto converted{evaluate::ConvertToType(type, SomeExpr{*expr})}) {
646         arg = std::move(*converted);
647       }
648     }
649   }
650 }
651 
652 static void CheckExplicitInterfaceArg(evaluate::ActualArgument &arg,
653     const characteristics::DummyArgument &dummy,
654     const characteristics::Procedure &proc, evaluate::FoldingContext &context,
655     const Scope *scope, const evaluate::SpecificIntrinsic *intrinsic,
656     bool allowIntegerConversions) {
657   auto &messages{context.messages()};
658   std::string dummyName{"dummy argument"};
659   if (!dummy.name.empty()) {
660     dummyName += " '"s + parser::ToLowerCaseLetters(dummy.name) + "='";
661   }
662   auto restorer{
663       messages.SetLocation(arg.sourceLocation().value_or(messages.at()))};
664   std::visit(
665       common::visitors{
666           [&](const characteristics::DummyDataObject &object) {
667             ConvertBOZLiteralArg(arg, object.type.type());
668             if (auto *expr{arg.UnwrapExpr()}) {
669               if (auto type{characteristics::TypeAndShape::Characterize(
670                       *expr, context)}) {
671                 arg.set_dummyIntent(object.intent);
672                 bool isElemental{object.type.Rank() == 0 && proc.IsElemental()};
673                 CheckExplicitDataArg(object, dummyName, *expr, *type,
674                     isElemental, context, scope, intrinsic,
675                     allowIntegerConversions);
676               } else if (object.type.type().IsTypelessIntrinsicArgument() &&
677                   IsBOZLiteral(*expr)) {
678                 // ok
679               } else if (object.type.type().IsTypelessIntrinsicArgument() &&
680                   evaluate::IsNullPointer(*expr)) {
681                 // ok, ASSOCIATED(NULL())
682               } else if ((object.attrs.test(characteristics::DummyDataObject::
683                                   Attr::Pointer) ||
684                              object.attrs.test(characteristics::
685                                      DummyDataObject::Attr::Optional)) &&
686                   evaluate::IsNullPointer(*expr)) {
687                 // ok, FOO(NULL())
688               } else {
689                 messages.Say(
690                     "Actual argument '%s' associated with %s is not a variable or typed expression"_err_en_US,
691                     expr->AsFortran(), dummyName);
692               }
693             } else {
694               const Symbol &assumed{DEREF(arg.GetAssumedTypeDummy())};
695               if (!object.type.type().IsAssumedType()) {
696                 messages.Say(
697                     "Assumed-type '%s' may be associated only with an assumed-type %s"_err_en_US,
698                     assumed.name(), dummyName);
699               } else if (object.type.attrs().test(evaluate::characteristics::
700                                  TypeAndShape::Attr::AssumedRank) &&
701                   !IsAssumedShape(assumed) &&
702                   !evaluate::IsAssumedRank(assumed)) {
703                 messages.Say( // C711
704                     "Assumed-type '%s' must be either assumed shape or assumed rank to be associated with assumed rank %s"_err_en_US,
705                     assumed.name(), dummyName);
706               }
707             }
708           },
709           [&](const characteristics::DummyProcedure &dummy) {
710             CheckProcedureArg(arg, proc, dummy, dummyName, context);
711           },
712           [&](const characteristics::AlternateReturn &) {
713             // All semantic checking is done elsewhere
714           },
715       },
716       dummy.u);
717 }
718 
719 static void RearrangeArguments(const characteristics::Procedure &proc,
720     evaluate::ActualArguments &actuals, parser::ContextualMessages &messages) {
721   CHECK(proc.HasExplicitInterface());
722   if (actuals.size() < proc.dummyArguments.size()) {
723     actuals.resize(proc.dummyArguments.size());
724   } else if (actuals.size() > proc.dummyArguments.size()) {
725     messages.Say(
726         "Too many actual arguments (%zd) passed to procedure that expects only %zd"_err_en_US,
727         actuals.size(), proc.dummyArguments.size());
728   }
729   std::map<std::string, evaluate::ActualArgument> kwArgs;
730   for (auto &x : actuals) {
731     if (x && x->keyword()) {
732       auto emplaced{
733           kwArgs.try_emplace(x->keyword()->ToString(), std::move(*x))};
734       if (!emplaced.second) {
735         messages.Say(*x->keyword(),
736             "Argument keyword '%s=' appears on more than one effective argument in this procedure reference"_err_en_US,
737             *x->keyword());
738       }
739       x.reset();
740     }
741   }
742   if (!kwArgs.empty()) {
743     int index{0};
744     for (const auto &dummy : proc.dummyArguments) {
745       if (!dummy.name.empty()) {
746         auto iter{kwArgs.find(dummy.name)};
747         if (iter != kwArgs.end()) {
748           evaluate::ActualArgument &x{iter->second};
749           if (actuals[index]) {
750             messages.Say(*x.keyword(),
751                 "Keyword argument '%s=' has already been specified positionally (#%d) in this procedure reference"_err_en_US,
752                 *x.keyword(), index + 1);
753           } else {
754             actuals[index] = std::move(x);
755           }
756           kwArgs.erase(iter);
757         }
758       }
759       ++index;
760     }
761     for (auto &bad : kwArgs) {
762       evaluate::ActualArgument &x{bad.second};
763       messages.Say(*x.keyword(),
764           "Argument keyword '%s=' is not recognized for this procedure reference"_err_en_US,
765           *x.keyword());
766     }
767   }
768 }
769 
770 // The actual argument arrays to an ELEMENTAL procedure must conform.
771 static bool CheckElementalConformance(parser::ContextualMessages &messages,
772     const characteristics::Procedure &proc, evaluate::ActualArguments &actuals,
773     evaluate::FoldingContext &context) {
774   std::optional<evaluate::Shape> shape;
775   std::string shapeName;
776   int index{0};
777   for (const auto &arg : actuals) {
778     const auto &dummy{proc.dummyArguments.at(index++)};
779     if (arg) {
780       if (const auto *expr{arg->UnwrapExpr()}) {
781         if (auto argShape{evaluate::GetShape(context, *expr)}) {
782           if (GetRank(*argShape) > 0) {
783             std::string argName{"actual argument ("s + expr->AsFortran() +
784                 ") corresponding to dummy argument #" + std::to_string(index) +
785                 " ('" + dummy.name + "')"};
786             if (shape) {
787               auto tristate{evaluate::CheckConformance(messages, *shape,
788                   *argShape, evaluate::CheckConformanceFlags::None,
789                   shapeName.c_str(), argName.c_str())};
790               if (tristate && !*tristate) {
791                 return false;
792               }
793             } else {
794               shape = std::move(argShape);
795               shapeName = argName;
796             }
797           }
798         }
799       }
800     }
801   }
802   return true;
803 }
804 
805 static parser::Messages CheckExplicitInterface(
806     const characteristics::Procedure &proc, evaluate::ActualArguments &actuals,
807     const evaluate::FoldingContext &context, const Scope *scope,
808     const evaluate::SpecificIntrinsic *intrinsic,
809     bool allowIntegerConversions) {
810   parser::Messages buffer;
811   parser::ContextualMessages messages{context.messages().at(), &buffer};
812   RearrangeArguments(proc, actuals, messages);
813   if (buffer.empty()) {
814     int index{0};
815     evaluate::FoldingContext localContext{context, messages};
816     for (auto &actual : actuals) {
817       const auto &dummy{proc.dummyArguments.at(index++)};
818       if (actual) {
819         CheckExplicitInterfaceArg(*actual, dummy, proc, localContext, scope,
820             intrinsic, allowIntegerConversions);
821       } else if (!dummy.IsOptional()) {
822         if (dummy.name.empty()) {
823           messages.Say(
824               "Dummy argument #%d is not OPTIONAL and is not associated with "
825               "an actual argument in this procedure reference"_err_en_US,
826               index);
827         } else {
828           messages.Say("Dummy argument '%s=' (#%d) is not OPTIONAL and is not "
829                        "associated with an actual argument in this procedure "
830                        "reference"_err_en_US,
831               dummy.name, index);
832         }
833       }
834     }
835     if (proc.IsElemental() && !buffer.AnyFatalError()) {
836       CheckElementalConformance(messages, proc, actuals, localContext);
837     }
838   }
839   return buffer;
840 }
841 
842 parser::Messages CheckExplicitInterface(const characteristics::Procedure &proc,
843     evaluate::ActualArguments &actuals, const evaluate::FoldingContext &context,
844     const Scope &scope, const evaluate::SpecificIntrinsic *intrinsic) {
845   return CheckExplicitInterface(
846       proc, actuals, context, &scope, intrinsic, true);
847 }
848 
849 bool CheckInterfaceForGeneric(const characteristics::Procedure &proc,
850     evaluate::ActualArguments &actuals, const evaluate::FoldingContext &context,
851     bool allowIntegerConversions) {
852   return !CheckExplicitInterface(
853       proc, actuals, context, nullptr, nullptr, allowIntegerConversions)
854               .AnyFatalError();
855 }
856 
857 void CheckArguments(const characteristics::Procedure &proc,
858     evaluate::ActualArguments &actuals, evaluate::FoldingContext &context,
859     const Scope &scope, bool treatingExternalAsImplicit,
860     const evaluate::SpecificIntrinsic *intrinsic) {
861   bool explicitInterface{proc.HasExplicitInterface()};
862   parser::ContextualMessages &messages{context.messages()};
863   if (!explicitInterface || treatingExternalAsImplicit) {
864     parser::Messages buffer;
865     {
866       auto restorer{messages.SetMessages(buffer)};
867       for (auto &actual : actuals) {
868         if (actual) {
869           CheckImplicitInterfaceArg(*actual, messages);
870         }
871       }
872     }
873     if (!buffer.empty()) {
874       if (auto *msgs{messages.messages()}) {
875         msgs->Annex(std::move(buffer));
876       }
877       return; // don't pile on
878     }
879   }
880   if (explicitInterface) {
881     auto buffer{
882         CheckExplicitInterface(proc, actuals, context, scope, intrinsic)};
883     if (treatingExternalAsImplicit && !buffer.empty()) {
884       if (auto *msg{messages.Say(
885               "Warning: if the procedure's interface were explicit, this reference would be in error:"_en_US)}) {
886         buffer.AttachTo(*msg);
887       }
888     }
889     if (auto *msgs{messages.messages()}) {
890       msgs->Annex(std::move(buffer));
891     }
892   }
893 }
894 } // namespace Fortran::semantics
895