1 //===------- SemaTemplateDeduction.cpp - Template Argument Deduction ------===/
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //===----------------------------------------------------------------------===/
9 // This file implements C++ template argument deduction.
11 //===----------------------------------------------------------------------===/
13 #include "clang/Sema/TemplateDeduction.h"
14 #include "TreeTransform.h"
15 #include "clang/AST/ASTContext.h"
16 #include "clang/AST/ASTLambda.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/AST/Expr.h"
20 #include "clang/AST/ExprCXX.h"
21 #include "clang/AST/StmtVisitor.h"
22 #include "clang/Sema/DeclSpec.h"
23 #include "clang/Sema/Sema.h"
24 #include "clang/Sema/Template.h"
25 #include "llvm/ADT/SmallBitVector.h"
30 /// \brief Various flags that control template argument deduction.
32 /// These flags can be bitwise-OR'd together.
33 enum TemplateDeductionFlags {
34 /// \brief No template argument deduction flags, which indicates the
35 /// strictest results for template argument deduction (as used for, e.g.,
36 /// matching class template partial specializations).
38 /// \brief Within template argument deduction from a function call, we are
39 /// matching with a parameter type for which the original parameter was
41 TDF_ParamWithReferenceType = 0x1,
42 /// \brief Within template argument deduction from a function call, we
43 /// are matching in a case where we ignore cv-qualifiers.
44 TDF_IgnoreQualifiers = 0x02,
45 /// \brief Within template argument deduction from a function call,
46 /// we are matching in a case where we can perform template argument
47 /// deduction from a template-id of a derived class of the argument type.
48 TDF_DerivedClass = 0x04,
49 /// \brief Allow non-dependent types to differ, e.g., when performing
50 /// template argument deduction from a function call where conversions
52 TDF_SkipNonDependent = 0x08,
53 /// \brief Whether we are performing template argument deduction for
54 /// parameters and arguments in a top-level template argument
55 TDF_TopLevelParameterTypeList = 0x10,
56 /// \brief Within template argument deduction from overload resolution per
57 /// C++ [over.over] allow matching function types that are compatible in
58 /// terms of noreturn and default calling convention adjustments.
59 TDF_InOverloadResolution = 0x20
63 using namespace clang;
65 /// \brief Compare two APSInts, extending and switching the sign as
66 /// necessary to compare their values regardless of underlying type.
67 static bool hasSameExtendedValue(llvm::APSInt X, llvm::APSInt Y) {
68 if (Y.getBitWidth() > X.getBitWidth())
69 X = X.extend(Y.getBitWidth());
70 else if (Y.getBitWidth() < X.getBitWidth())
71 Y = Y.extend(X.getBitWidth());
73 // If there is a signedness mismatch, correct it.
74 if (X.isSigned() != Y.isSigned()) {
75 // If the signed value is negative, then the values cannot be the same.
76 if ((Y.isSigned() && Y.isNegative()) || (X.isSigned() && X.isNegative()))
86 static Sema::TemplateDeductionResult
87 DeduceTemplateArguments(Sema &S,
88 TemplateParameterList *TemplateParams,
89 const TemplateArgument &Param,
91 TemplateDeductionInfo &Info,
92 SmallVectorImpl<DeducedTemplateArgument> &Deduced);
94 static Sema::TemplateDeductionResult
95 DeduceTemplateArgumentsByTypeMatch(Sema &S,
96 TemplateParameterList *TemplateParams,
99 TemplateDeductionInfo &Info,
100 SmallVectorImpl<DeducedTemplateArgument> &
103 bool PartialOrdering = false);
105 static Sema::TemplateDeductionResult
106 DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
107 const TemplateArgument *Params, unsigned NumParams,
108 const TemplateArgument *Args, unsigned NumArgs,
109 TemplateDeductionInfo &Info,
110 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
111 bool NumberOfArgumentsMustMatch);
113 /// \brief If the given expression is of a form that permits the deduction
114 /// of a non-type template parameter, return the declaration of that
115 /// non-type template parameter.
116 static NonTypeTemplateParmDecl *getDeducedParameterFromExpr(Expr *E) {
117 // If we are within an alias template, the expression may have undergone
118 // any number of parameter substitutions already.
120 if (ImplicitCastExpr *IC = dyn_cast<ImplicitCastExpr>(E))
121 E = IC->getSubExpr();
122 else if (SubstNonTypeTemplateParmExpr *Subst =
123 dyn_cast<SubstNonTypeTemplateParmExpr>(E))
124 E = Subst->getReplacement();
129 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E))
130 return dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
135 /// \brief Determine whether two declaration pointers refer to the same
137 static bool isSameDeclaration(Decl *X, Decl *Y) {
138 if (NamedDecl *NX = dyn_cast<NamedDecl>(X))
139 X = NX->getUnderlyingDecl();
140 if (NamedDecl *NY = dyn_cast<NamedDecl>(Y))
141 Y = NY->getUnderlyingDecl();
143 return X->getCanonicalDecl() == Y->getCanonicalDecl();
146 /// \brief Verify that the given, deduced template arguments are compatible.
148 /// \returns The deduced template argument, or a NULL template argument if
149 /// the deduced template arguments were incompatible.
150 static DeducedTemplateArgument
151 checkDeducedTemplateArguments(ASTContext &Context,
152 const DeducedTemplateArgument &X,
153 const DeducedTemplateArgument &Y) {
154 // We have no deduction for one or both of the arguments; they're compatible.
160 switch (X.getKind()) {
161 case TemplateArgument::Null:
162 llvm_unreachable("Non-deduced template arguments handled above");
164 case TemplateArgument::Type:
165 // If two template type arguments have the same type, they're compatible.
166 if (Y.getKind() == TemplateArgument::Type &&
167 Context.hasSameType(X.getAsType(), Y.getAsType()))
170 return DeducedTemplateArgument();
172 case TemplateArgument::Integral:
173 // If we deduced a constant in one case and either a dependent expression or
174 // declaration in another case, keep the integral constant.
175 // If both are integral constants with the same value, keep that value.
176 if (Y.getKind() == TemplateArgument::Expression ||
177 Y.getKind() == TemplateArgument::Declaration ||
178 (Y.getKind() == TemplateArgument::Integral &&
179 hasSameExtendedValue(X.getAsIntegral(), Y.getAsIntegral())))
180 return DeducedTemplateArgument(X,
181 X.wasDeducedFromArrayBound() &&
182 Y.wasDeducedFromArrayBound());
184 // All other combinations are incompatible.
185 return DeducedTemplateArgument();
187 case TemplateArgument::Template:
188 if (Y.getKind() == TemplateArgument::Template &&
189 Context.hasSameTemplateName(X.getAsTemplate(), Y.getAsTemplate()))
192 // All other combinations are incompatible.
193 return DeducedTemplateArgument();
195 case TemplateArgument::TemplateExpansion:
196 if (Y.getKind() == TemplateArgument::TemplateExpansion &&
197 Context.hasSameTemplateName(X.getAsTemplateOrTemplatePattern(),
198 Y.getAsTemplateOrTemplatePattern()))
201 // All other combinations are incompatible.
202 return DeducedTemplateArgument();
204 case TemplateArgument::Expression:
205 // If we deduced a dependent expression in one case and either an integral
206 // constant or a declaration in another case, keep the integral constant
208 if (Y.getKind() == TemplateArgument::Integral ||
209 Y.getKind() == TemplateArgument::Declaration)
210 return DeducedTemplateArgument(Y, X.wasDeducedFromArrayBound() &&
211 Y.wasDeducedFromArrayBound());
213 if (Y.getKind() == TemplateArgument::Expression) {
214 // Compare the expressions for equality
215 llvm::FoldingSetNodeID ID1, ID2;
216 X.getAsExpr()->Profile(ID1, Context, true);
217 Y.getAsExpr()->Profile(ID2, Context, true);
222 // All other combinations are incompatible.
223 return DeducedTemplateArgument();
225 case TemplateArgument::Declaration:
226 // If we deduced a declaration and a dependent expression, keep the
228 if (Y.getKind() == TemplateArgument::Expression)
231 // If we deduced a declaration and an integral constant, keep the
232 // integral constant.
233 if (Y.getKind() == TemplateArgument::Integral)
236 // If we deduced two declarations, make sure they they refer to the
238 if (Y.getKind() == TemplateArgument::Declaration &&
239 isSameDeclaration(X.getAsDecl(), Y.getAsDecl()))
242 // All other combinations are incompatible.
243 return DeducedTemplateArgument();
245 case TemplateArgument::NullPtr:
246 // If we deduced a null pointer and a dependent expression, keep the
248 if (Y.getKind() == TemplateArgument::Expression)
251 // If we deduced a null pointer and an integral constant, keep the
252 // integral constant.
253 if (Y.getKind() == TemplateArgument::Integral)
256 // If we deduced two null pointers, make sure they have the same type.
257 if (Y.getKind() == TemplateArgument::NullPtr &&
258 Context.hasSameType(X.getNullPtrType(), Y.getNullPtrType()))
261 // All other combinations are incompatible.
262 return DeducedTemplateArgument();
264 case TemplateArgument::Pack:
265 if (Y.getKind() != TemplateArgument::Pack ||
266 X.pack_size() != Y.pack_size())
267 return DeducedTemplateArgument();
269 for (TemplateArgument::pack_iterator XA = X.pack_begin(),
270 XAEnd = X.pack_end(),
272 XA != XAEnd; ++XA, ++YA) {
273 // FIXME: Do we need to merge the results together here?
274 if (checkDeducedTemplateArguments(Context,
275 DeducedTemplateArgument(*XA, X.wasDeducedFromArrayBound()),
276 DeducedTemplateArgument(*YA, Y.wasDeducedFromArrayBound()))
278 return DeducedTemplateArgument();
284 llvm_unreachable("Invalid TemplateArgument Kind!");
287 /// \brief Deduce the value of the given non-type template parameter
288 /// from the given constant.
289 static Sema::TemplateDeductionResult DeduceNonTypeTemplateArgument(
290 Sema &S, NonTypeTemplateParmDecl *NTTP, const llvm::APSInt &Value,
291 QualType ValueType, bool DeducedFromArrayBound, TemplateDeductionInfo &Info,
292 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
293 assert(NTTP->getDepth() == 0 &&
294 "Cannot deduce non-type template argument with depth > 0");
296 DeducedTemplateArgument NewDeduced(S.Context, Value, ValueType,
297 DeducedFromArrayBound);
298 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
299 Deduced[NTTP->getIndex()],
301 if (Result.isNull()) {
303 Info.FirstArg = Deduced[NTTP->getIndex()];
304 Info.SecondArg = NewDeduced;
305 return Sema::TDK_Inconsistent;
308 Deduced[NTTP->getIndex()] = Result;
309 return Sema::TDK_Success;
312 /// \brief Deduce the value of the given non-type template parameter
313 /// from the given type- or value-dependent expression.
315 /// \returns true if deduction succeeded, false otherwise.
316 static Sema::TemplateDeductionResult
317 DeduceNonTypeTemplateArgument(Sema &S,
318 NonTypeTemplateParmDecl *NTTP,
320 TemplateDeductionInfo &Info,
321 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
322 assert(NTTP->getDepth() == 0 &&
323 "Cannot deduce non-type template argument with depth > 0");
324 assert((Value->isTypeDependent() || Value->isValueDependent()) &&
325 "Expression template argument must be type- or value-dependent.");
327 DeducedTemplateArgument NewDeduced(Value);
328 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
329 Deduced[NTTP->getIndex()],
332 if (Result.isNull()) {
334 Info.FirstArg = Deduced[NTTP->getIndex()];
335 Info.SecondArg = NewDeduced;
336 return Sema::TDK_Inconsistent;
339 Deduced[NTTP->getIndex()] = Result;
340 return Sema::TDK_Success;
343 /// \brief Deduce the value of the given non-type template parameter
344 /// from the given declaration.
346 /// \returns true if deduction succeeded, false otherwise.
347 static Sema::TemplateDeductionResult
348 DeduceNonTypeTemplateArgument(Sema &S,
349 NonTypeTemplateParmDecl *NTTP,
351 TemplateDeductionInfo &Info,
352 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
353 assert(NTTP->getDepth() == 0 &&
354 "Cannot deduce non-type template argument with depth > 0");
356 D = D ? cast<ValueDecl>(D->getCanonicalDecl()) : nullptr;
357 TemplateArgument New(D, NTTP->getType());
358 DeducedTemplateArgument NewDeduced(New);
359 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
360 Deduced[NTTP->getIndex()],
362 if (Result.isNull()) {
364 Info.FirstArg = Deduced[NTTP->getIndex()];
365 Info.SecondArg = NewDeduced;
366 return Sema::TDK_Inconsistent;
369 Deduced[NTTP->getIndex()] = Result;
370 return Sema::TDK_Success;
373 static Sema::TemplateDeductionResult
374 DeduceTemplateArguments(Sema &S,
375 TemplateParameterList *TemplateParams,
378 TemplateDeductionInfo &Info,
379 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
380 TemplateDecl *ParamDecl = Param.getAsTemplateDecl();
382 // The parameter type is dependent and is not a template template parameter,
383 // so there is nothing that we can deduce.
384 return Sema::TDK_Success;
387 if (TemplateTemplateParmDecl *TempParam
388 = dyn_cast<TemplateTemplateParmDecl>(ParamDecl)) {
389 DeducedTemplateArgument NewDeduced(S.Context.getCanonicalTemplateName(Arg));
390 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
391 Deduced[TempParam->getIndex()],
393 if (Result.isNull()) {
394 Info.Param = TempParam;
395 Info.FirstArg = Deduced[TempParam->getIndex()];
396 Info.SecondArg = NewDeduced;
397 return Sema::TDK_Inconsistent;
400 Deduced[TempParam->getIndex()] = Result;
401 return Sema::TDK_Success;
404 // Verify that the two template names are equivalent.
405 if (S.Context.hasSameTemplateName(Param, Arg))
406 return Sema::TDK_Success;
408 // Mismatch of non-dependent template parameter to argument.
409 Info.FirstArg = TemplateArgument(Param);
410 Info.SecondArg = TemplateArgument(Arg);
411 return Sema::TDK_NonDeducedMismatch;
414 /// \brief Deduce the template arguments by comparing the template parameter
415 /// type (which is a template-id) with the template argument type.
417 /// \param S the Sema
419 /// \param TemplateParams the template parameters that we are deducing
421 /// \param Param the parameter type
423 /// \param Arg the argument type
425 /// \param Info information about the template argument deduction itself
427 /// \param Deduced the deduced template arguments
429 /// \returns the result of template argument deduction so far. Note that a
430 /// "success" result means that template argument deduction has not yet failed,
431 /// but it may still fail, later, for other reasons.
432 static Sema::TemplateDeductionResult
433 DeduceTemplateArguments(Sema &S,
434 TemplateParameterList *TemplateParams,
435 const TemplateSpecializationType *Param,
437 TemplateDeductionInfo &Info,
438 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
439 assert(Arg.isCanonical() && "Argument type must be canonical");
441 // Check whether the template argument is a dependent template-id.
442 if (const TemplateSpecializationType *SpecArg
443 = dyn_cast<TemplateSpecializationType>(Arg)) {
444 // Perform template argument deduction for the template name.
445 if (Sema::TemplateDeductionResult Result
446 = DeduceTemplateArguments(S, TemplateParams,
447 Param->getTemplateName(),
448 SpecArg->getTemplateName(),
453 // Perform template argument deduction on each template
454 // argument. Ignore any missing/extra arguments, since they could be
455 // filled in by default arguments.
456 return DeduceTemplateArguments(S, TemplateParams, Param->getArgs(),
457 Param->getNumArgs(), SpecArg->getArgs(),
458 SpecArg->getNumArgs(), Info, Deduced,
459 /*NumberOfArgumentsMustMatch=*/false);
462 // If the argument type is a class template specialization, we
463 // perform template argument deduction using its template
465 const RecordType *RecordArg = dyn_cast<RecordType>(Arg);
467 Info.FirstArg = TemplateArgument(QualType(Param, 0));
468 Info.SecondArg = TemplateArgument(Arg);
469 return Sema::TDK_NonDeducedMismatch;
472 ClassTemplateSpecializationDecl *SpecArg
473 = dyn_cast<ClassTemplateSpecializationDecl>(RecordArg->getDecl());
475 Info.FirstArg = TemplateArgument(QualType(Param, 0));
476 Info.SecondArg = TemplateArgument(Arg);
477 return Sema::TDK_NonDeducedMismatch;
480 // Perform template argument deduction for the template name.
481 if (Sema::TemplateDeductionResult Result
482 = DeduceTemplateArguments(S,
484 Param->getTemplateName(),
485 TemplateName(SpecArg->getSpecializedTemplate()),
489 // Perform template argument deduction for the template arguments.
490 return DeduceTemplateArguments(
491 S, TemplateParams, Param->getArgs(), Param->getNumArgs(),
492 SpecArg->getTemplateArgs().data(), SpecArg->getTemplateArgs().size(),
493 Info, Deduced, /*NumberOfArgumentsMustMatch=*/true);
496 /// \brief Determines whether the given type is an opaque type that
497 /// might be more qualified when instantiated.
498 static bool IsPossiblyOpaquelyQualifiedType(QualType T) {
499 switch (T->getTypeClass()) {
500 case Type::TypeOfExpr:
502 case Type::DependentName:
504 case Type::UnresolvedUsing:
505 case Type::TemplateTypeParm:
508 case Type::ConstantArray:
509 case Type::IncompleteArray:
510 case Type::VariableArray:
511 case Type::DependentSizedArray:
512 return IsPossiblyOpaquelyQualifiedType(
513 cast<ArrayType>(T)->getElementType());
520 /// \brief Retrieve the depth and index of a template parameter.
521 static std::pair<unsigned, unsigned>
522 getDepthAndIndex(NamedDecl *ND) {
523 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(ND))
524 return std::make_pair(TTP->getDepth(), TTP->getIndex());
526 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(ND))
527 return std::make_pair(NTTP->getDepth(), NTTP->getIndex());
529 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(ND);
530 return std::make_pair(TTP->getDepth(), TTP->getIndex());
533 /// \brief Retrieve the depth and index of an unexpanded parameter pack.
534 static std::pair<unsigned, unsigned>
535 getDepthAndIndex(UnexpandedParameterPack UPP) {
536 if (const TemplateTypeParmType *TTP
537 = UPP.first.dyn_cast<const TemplateTypeParmType *>())
538 return std::make_pair(TTP->getDepth(), TTP->getIndex());
540 return getDepthAndIndex(UPP.first.get<NamedDecl *>());
543 /// \brief Helper function to build a TemplateParameter when we don't
544 /// know its type statically.
545 static TemplateParameter makeTemplateParameter(Decl *D) {
546 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(D))
547 return TemplateParameter(TTP);
548 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(D))
549 return TemplateParameter(NTTP);
551 return TemplateParameter(cast<TemplateTemplateParmDecl>(D));
554 /// A pack that we're currently deducing.
555 struct clang::DeducedPack {
556 DeducedPack(unsigned Index) : Index(Index), Outer(nullptr) {}
558 // The index of the pack.
561 // The old value of the pack before we started deducing it.
562 DeducedTemplateArgument Saved;
564 // A deferred value of this pack from an inner deduction, that couldn't be
565 // deduced because this deduction hadn't happened yet.
566 DeducedTemplateArgument DeferredDeduction;
568 // The new value of the pack.
569 SmallVector<DeducedTemplateArgument, 4> New;
571 // The outer deduction for this pack, if any.
576 /// A scope in which we're performing pack deduction.
577 class PackDeductionScope {
579 PackDeductionScope(Sema &S, TemplateParameterList *TemplateParams,
580 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
581 TemplateDeductionInfo &Info, TemplateArgument Pattern)
582 : S(S), TemplateParams(TemplateParams), Deduced(Deduced), Info(Info) {
583 // Compute the set of template parameter indices that correspond to
584 // parameter packs expanded by the pack expansion.
586 llvm::SmallBitVector SawIndices(TemplateParams->size());
587 SmallVector<UnexpandedParameterPack, 2> Unexpanded;
588 S.collectUnexpandedParameterPacks(Pattern, Unexpanded);
589 for (unsigned I = 0, N = Unexpanded.size(); I != N; ++I) {
590 unsigned Depth, Index;
591 std::tie(Depth, Index) = getDepthAndIndex(Unexpanded[I]);
592 if (Depth == 0 && !SawIndices[Index]) {
593 SawIndices[Index] = true;
595 // Save the deduced template argument for the parameter pack expanded
596 // by this pack expansion, then clear out the deduction.
597 DeducedPack Pack(Index);
598 Pack.Saved = Deduced[Index];
599 Deduced[Index] = TemplateArgument();
601 Packs.push_back(Pack);
605 assert(!Packs.empty() && "Pack expansion without unexpanded packs?");
607 for (auto &Pack : Packs) {
608 if (Info.PendingDeducedPacks.size() > Pack.Index)
609 Pack.Outer = Info.PendingDeducedPacks[Pack.Index];
611 Info.PendingDeducedPacks.resize(Pack.Index + 1);
612 Info.PendingDeducedPacks[Pack.Index] = &Pack;
614 if (S.CurrentInstantiationScope) {
615 // If the template argument pack was explicitly specified, add that to
616 // the set of deduced arguments.
617 const TemplateArgument *ExplicitArgs;
618 unsigned NumExplicitArgs;
619 NamedDecl *PartiallySubstitutedPack =
620 S.CurrentInstantiationScope->getPartiallySubstitutedPack(
621 &ExplicitArgs, &NumExplicitArgs);
622 if (PartiallySubstitutedPack &&
623 getDepthAndIndex(PartiallySubstitutedPack).second == Pack.Index)
624 Pack.New.append(ExplicitArgs, ExplicitArgs + NumExplicitArgs);
629 ~PackDeductionScope() {
630 for (auto &Pack : Packs)
631 Info.PendingDeducedPacks[Pack.Index] = Pack.Outer;
634 /// Move to deducing the next element in each pack that is being deduced.
635 void nextPackElement() {
636 // Capture the deduced template arguments for each parameter pack expanded
637 // by this pack expansion, add them to the list of arguments we've deduced
638 // for that pack, then clear out the deduced argument.
639 for (auto &Pack : Packs) {
640 DeducedTemplateArgument &DeducedArg = Deduced[Pack.Index];
641 if (!DeducedArg.isNull()) {
642 Pack.New.push_back(DeducedArg);
643 DeducedArg = DeducedTemplateArgument();
648 /// \brief Finish template argument deduction for a set of argument packs,
649 /// producing the argument packs and checking for consistency with prior
651 Sema::TemplateDeductionResult finish(bool HasAnyArguments) {
652 // Build argument packs for each of the parameter packs expanded by this
654 for (auto &Pack : Packs) {
655 // Put back the old value for this pack.
656 Deduced[Pack.Index] = Pack.Saved;
658 // Build or find a new value for this pack.
659 DeducedTemplateArgument NewPack;
660 if (HasAnyArguments && Pack.New.empty()) {
661 if (Pack.DeferredDeduction.isNull()) {
662 // We were not able to deduce anything for this parameter pack
663 // (because it only appeared in non-deduced contexts), so just
664 // restore the saved argument pack.
668 NewPack = Pack.DeferredDeduction;
669 Pack.DeferredDeduction = TemplateArgument();
670 } else if (Pack.New.empty()) {
671 // If we deduced an empty argument pack, create it now.
672 NewPack = DeducedTemplateArgument(TemplateArgument::getEmptyPack());
674 TemplateArgument *ArgumentPack =
675 new (S.Context) TemplateArgument[Pack.New.size()];
676 std::copy(Pack.New.begin(), Pack.New.end(), ArgumentPack);
677 NewPack = DeducedTemplateArgument(
678 TemplateArgument(llvm::makeArrayRef(ArgumentPack, Pack.New.size())),
679 Pack.New[0].wasDeducedFromArrayBound());
682 // Pick where we're going to put the merged pack.
683 DeducedTemplateArgument *Loc;
685 if (Pack.Outer->DeferredDeduction.isNull()) {
686 // Defer checking this pack until we have a complete pack to compare
688 Pack.Outer->DeferredDeduction = NewPack;
691 Loc = &Pack.Outer->DeferredDeduction;
693 Loc = &Deduced[Pack.Index];
696 // Check the new pack matches any previous value.
697 DeducedTemplateArgument OldPack = *Loc;
698 DeducedTemplateArgument Result =
699 checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
701 // If we deferred a deduction of this pack, check that one now too.
702 if (!Result.isNull() && !Pack.DeferredDeduction.isNull()) {
704 NewPack = Pack.DeferredDeduction;
705 Result = checkDeducedTemplateArguments(S.Context, OldPack, NewPack);
708 if (Result.isNull()) {
710 makeTemplateParameter(TemplateParams->getParam(Pack.Index));
711 Info.FirstArg = OldPack;
712 Info.SecondArg = NewPack;
713 return Sema::TDK_Inconsistent;
719 return Sema::TDK_Success;
724 TemplateParameterList *TemplateParams;
725 SmallVectorImpl<DeducedTemplateArgument> &Deduced;
726 TemplateDeductionInfo &Info;
728 SmallVector<DeducedPack, 2> Packs;
732 /// \brief Deduce the template arguments by comparing the list of parameter
733 /// types to the list of argument types, as in the parameter-type-lists of
734 /// function types (C++ [temp.deduct.type]p10).
736 /// \param S The semantic analysis object within which we are deducing
738 /// \param TemplateParams The template parameters that we are deducing
740 /// \param Params The list of parameter types
742 /// \param NumParams The number of types in \c Params
744 /// \param Args The list of argument types
746 /// \param NumArgs The number of types in \c Args
748 /// \param Info information about the template argument deduction itself
750 /// \param Deduced the deduced template arguments
752 /// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
753 /// how template argument deduction is performed.
755 /// \param PartialOrdering If true, we are performing template argument
756 /// deduction for during partial ordering for a call
757 /// (C++0x [temp.deduct.partial]).
759 /// \returns the result of template argument deduction so far. Note that a
760 /// "success" result means that template argument deduction has not yet failed,
761 /// but it may still fail, later, for other reasons.
762 static Sema::TemplateDeductionResult
763 DeduceTemplateArguments(Sema &S,
764 TemplateParameterList *TemplateParams,
765 const QualType *Params, unsigned NumParams,
766 const QualType *Args, unsigned NumArgs,
767 TemplateDeductionInfo &Info,
768 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
770 bool PartialOrdering = false) {
771 // Fast-path check to see if we have too many/too few arguments.
772 if (NumParams != NumArgs &&
773 !(NumParams && isa<PackExpansionType>(Params[NumParams - 1])) &&
774 !(NumArgs && isa<PackExpansionType>(Args[NumArgs - 1])))
775 return Sema::TDK_MiscellaneousDeductionFailure;
777 // C++0x [temp.deduct.type]p10:
778 // Similarly, if P has a form that contains (T), then each parameter type
779 // Pi of the respective parameter-type- list of P is compared with the
780 // corresponding parameter type Ai of the corresponding parameter-type-list
782 unsigned ArgIdx = 0, ParamIdx = 0;
783 for (; ParamIdx != NumParams; ++ParamIdx) {
784 // Check argument types.
785 const PackExpansionType *Expansion
786 = dyn_cast<PackExpansionType>(Params[ParamIdx]);
788 // Simple case: compare the parameter and argument types at this point.
790 // Make sure we have an argument.
791 if (ArgIdx >= NumArgs)
792 return Sema::TDK_MiscellaneousDeductionFailure;
794 if (isa<PackExpansionType>(Args[ArgIdx])) {
795 // C++0x [temp.deduct.type]p22:
796 // If the original function parameter associated with A is a function
797 // parameter pack and the function parameter associated with P is not
798 // a function parameter pack, then template argument deduction fails.
799 return Sema::TDK_MiscellaneousDeductionFailure;
802 if (Sema::TemplateDeductionResult Result
803 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
804 Params[ParamIdx], Args[ArgIdx],
813 // C++0x [temp.deduct.type]p5:
814 // The non-deduced contexts are:
815 // - A function parameter pack that does not occur at the end of the
816 // parameter-declaration-clause.
817 if (ParamIdx + 1 < NumParams)
818 return Sema::TDK_Success;
820 // C++0x [temp.deduct.type]p10:
821 // If the parameter-declaration corresponding to Pi is a function
822 // parameter pack, then the type of its declarator- id is compared with
823 // each remaining parameter type in the parameter-type-list of A. Each
824 // comparison deduces template arguments for subsequent positions in the
825 // template parameter packs expanded by the function parameter pack.
827 QualType Pattern = Expansion->getPattern();
828 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
830 bool HasAnyArguments = false;
831 for (; ArgIdx < NumArgs; ++ArgIdx) {
832 HasAnyArguments = true;
834 // Deduce template arguments from the pattern.
835 if (Sema::TemplateDeductionResult Result
836 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, Pattern,
837 Args[ArgIdx], Info, Deduced,
838 TDF, PartialOrdering))
841 PackScope.nextPackElement();
844 // Build argument packs for each of the parameter packs expanded by this
846 if (auto Result = PackScope.finish(HasAnyArguments))
850 // Make sure we don't have any extra arguments.
851 if (ArgIdx < NumArgs)
852 return Sema::TDK_MiscellaneousDeductionFailure;
854 return Sema::TDK_Success;
857 /// \brief Determine whether the parameter has qualifiers that are either
858 /// inconsistent with or a superset of the argument's qualifiers.
859 static bool hasInconsistentOrSupersetQualifiersOf(QualType ParamType,
861 Qualifiers ParamQs = ParamType.getQualifiers();
862 Qualifiers ArgQs = ArgType.getQualifiers();
864 if (ParamQs == ArgQs)
867 // Mismatched (but not missing) Objective-C GC attributes.
868 if (ParamQs.getObjCGCAttr() != ArgQs.getObjCGCAttr() &&
869 ParamQs.hasObjCGCAttr())
872 // Mismatched (but not missing) address spaces.
873 if (ParamQs.getAddressSpace() != ArgQs.getAddressSpace() &&
874 ParamQs.hasAddressSpace())
877 // Mismatched (but not missing) Objective-C lifetime qualifiers.
878 if (ParamQs.getObjCLifetime() != ArgQs.getObjCLifetime() &&
879 ParamQs.hasObjCLifetime())
882 // CVR qualifier superset.
883 return (ParamQs.getCVRQualifiers() != ArgQs.getCVRQualifiers()) &&
884 ((ParamQs.getCVRQualifiers() | ArgQs.getCVRQualifiers())
885 == ParamQs.getCVRQualifiers());
888 /// \brief Compare types for equality with respect to possibly compatible
889 /// function types (noreturn adjustment, implicit calling conventions). If any
890 /// of parameter and argument is not a function, just perform type comparison.
892 /// \param Param the template parameter type.
894 /// \param Arg the argument type.
895 bool Sema::isSameOrCompatibleFunctionType(CanQualType Param,
897 const FunctionType *ParamFunction = Param->getAs<FunctionType>(),
898 *ArgFunction = Arg->getAs<FunctionType>();
900 // Just compare if not functions.
901 if (!ParamFunction || !ArgFunction)
904 // Noreturn adjustment.
905 QualType AdjustedParam;
906 if (IsNoReturnConversion(Param, Arg, AdjustedParam))
907 return Arg == Context.getCanonicalType(AdjustedParam);
909 // FIXME: Compatible calling conventions.
914 /// \brief Deduce the template arguments by comparing the parameter type and
915 /// the argument type (C++ [temp.deduct.type]).
917 /// \param S the semantic analysis object within which we are deducing
919 /// \param TemplateParams the template parameters that we are deducing
921 /// \param ParamIn the parameter type
923 /// \param ArgIn the argument type
925 /// \param Info information about the template argument deduction itself
927 /// \param Deduced the deduced template arguments
929 /// \param TDF bitwise OR of the TemplateDeductionFlags bits that describe
930 /// how template argument deduction is performed.
932 /// \param PartialOrdering Whether we're performing template argument deduction
933 /// in the context of partial ordering (C++0x [temp.deduct.partial]).
935 /// \returns the result of template argument deduction so far. Note that a
936 /// "success" result means that template argument deduction has not yet failed,
937 /// but it may still fail, later, for other reasons.
938 static Sema::TemplateDeductionResult
939 DeduceTemplateArgumentsByTypeMatch(Sema &S,
940 TemplateParameterList *TemplateParams,
941 QualType ParamIn, QualType ArgIn,
942 TemplateDeductionInfo &Info,
943 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
945 bool PartialOrdering) {
946 // We only want to look at the canonical types, since typedefs and
947 // sugar are not part of template argument deduction.
948 QualType Param = S.Context.getCanonicalType(ParamIn);
949 QualType Arg = S.Context.getCanonicalType(ArgIn);
951 // If the argument type is a pack expansion, look at its pattern.
952 // This isn't explicitly called out
953 if (const PackExpansionType *ArgExpansion
954 = dyn_cast<PackExpansionType>(Arg))
955 Arg = ArgExpansion->getPattern();
957 if (PartialOrdering) {
958 // C++11 [temp.deduct.partial]p5:
959 // Before the partial ordering is done, certain transformations are
960 // performed on the types used for partial ordering:
961 // - If P is a reference type, P is replaced by the type referred to.
962 const ReferenceType *ParamRef = Param->getAs<ReferenceType>();
964 Param = ParamRef->getPointeeType();
966 // - If A is a reference type, A is replaced by the type referred to.
967 const ReferenceType *ArgRef = Arg->getAs<ReferenceType>();
969 Arg = ArgRef->getPointeeType();
971 if (ParamRef && ArgRef && S.Context.hasSameUnqualifiedType(Param, Arg)) {
972 // C++11 [temp.deduct.partial]p9:
973 // If, for a given type, deduction succeeds in both directions (i.e.,
974 // the types are identical after the transformations above) and both
975 // P and A were reference types [...]:
976 // - if [one type] was an lvalue reference and [the other type] was
977 // not, [the other type] is not considered to be at least as
978 // specialized as [the first type]
979 // - if [one type] is more cv-qualified than [the other type],
980 // [the other type] is not considered to be at least as specialized
981 // as [the first type]
982 // Objective-C ARC adds:
983 // - [one type] has non-trivial lifetime, [the other type] has
984 // __unsafe_unretained lifetime, and the types are otherwise
987 // A is "considered to be at least as specialized" as P iff deduction
988 // succeeds, so we model this as a deduction failure. Note that
989 // [the first type] is P and [the other type] is A here; the standard
990 // gets this backwards.
991 Qualifiers ParamQuals = Param.getQualifiers();
992 Qualifiers ArgQuals = Arg.getQualifiers();
993 if ((ParamRef->isLValueReferenceType() &&
994 !ArgRef->isLValueReferenceType()) ||
995 ParamQuals.isStrictSupersetOf(ArgQuals) ||
996 (ParamQuals.hasNonTrivialObjCLifetime() &&
997 ArgQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone &&
998 ParamQuals.withoutObjCLifetime() ==
999 ArgQuals.withoutObjCLifetime())) {
1000 Info.FirstArg = TemplateArgument(ParamIn);
1001 Info.SecondArg = TemplateArgument(ArgIn);
1002 return Sema::TDK_NonDeducedMismatch;
1006 // C++11 [temp.deduct.partial]p7:
1007 // Remove any top-level cv-qualifiers:
1008 // - If P is a cv-qualified type, P is replaced by the cv-unqualified
1010 Param = Param.getUnqualifiedType();
1011 // - If A is a cv-qualified type, A is replaced by the cv-unqualified
1013 Arg = Arg.getUnqualifiedType();
1015 // C++0x [temp.deduct.call]p4 bullet 1:
1016 // - If the original P is a reference type, the deduced A (i.e., the type
1017 // referred to by the reference) can be more cv-qualified than the
1019 if (TDF & TDF_ParamWithReferenceType) {
1021 QualType UnqualParam = S.Context.getUnqualifiedArrayType(Param, Quals);
1022 Quals.setCVRQualifiers(Quals.getCVRQualifiers() &
1023 Arg.getCVRQualifiers());
1024 Param = S.Context.getQualifiedType(UnqualParam, Quals);
1027 if ((TDF & TDF_TopLevelParameterTypeList) && !Param->isFunctionType()) {
1028 // C++0x [temp.deduct.type]p10:
1029 // If P and A are function types that originated from deduction when
1030 // taking the address of a function template (14.8.2.2) or when deducing
1031 // template arguments from a function declaration (14.8.2.6) and Pi and
1032 // Ai are parameters of the top-level parameter-type-list of P and A,
1033 // respectively, Pi is adjusted if it is an rvalue reference to a
1034 // cv-unqualified template parameter and Ai is an lvalue reference, in
1035 // which case the type of Pi is changed to be the template parameter
1036 // type (i.e., T&& is changed to simply T). [ Note: As a result, when
1037 // Pi is T&& and Ai is X&, the adjusted Pi will be T, causing T to be
1038 // deduced as X&. - end note ]
1039 TDF &= ~TDF_TopLevelParameterTypeList;
1041 if (const RValueReferenceType *ParamRef
1042 = Param->getAs<RValueReferenceType>()) {
1043 if (isa<TemplateTypeParmType>(ParamRef->getPointeeType()) &&
1044 !ParamRef->getPointeeType().getQualifiers())
1045 if (Arg->isLValueReferenceType())
1046 Param = ParamRef->getPointeeType();
1051 // C++ [temp.deduct.type]p9:
1052 // A template type argument T, a template template argument TT or a
1053 // template non-type argument i can be deduced if P and A have one of
1054 // the following forms:
1058 if (const TemplateTypeParmType *TemplateTypeParm
1059 = Param->getAs<TemplateTypeParmType>()) {
1060 // Just skip any attempts to deduce from a placeholder type.
1061 if (Arg->isPlaceholderType())
1062 return Sema::TDK_Success;
1064 unsigned Index = TemplateTypeParm->getIndex();
1065 bool RecanonicalizeArg = false;
1067 // If the argument type is an array type, move the qualifiers up to the
1068 // top level, so they can be matched with the qualifiers on the parameter.
1069 if (isa<ArrayType>(Arg)) {
1071 Arg = S.Context.getUnqualifiedArrayType(Arg, Quals);
1073 Arg = S.Context.getQualifiedType(Arg, Quals);
1074 RecanonicalizeArg = true;
1078 // The argument type can not be less qualified than the parameter
1080 if (!(TDF & TDF_IgnoreQualifiers) &&
1081 hasInconsistentOrSupersetQualifiersOf(Param, Arg)) {
1082 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1083 Info.FirstArg = TemplateArgument(Param);
1084 Info.SecondArg = TemplateArgument(Arg);
1085 return Sema::TDK_Underqualified;
1088 assert(TemplateTypeParm->getDepth() == 0 && "Can't deduce with depth > 0");
1089 assert(Arg != S.Context.OverloadTy && "Unresolved overloaded function");
1090 QualType DeducedType = Arg;
1092 // Remove any qualifiers on the parameter from the deduced type.
1093 // We checked the qualifiers for consistency above.
1094 Qualifiers DeducedQs = DeducedType.getQualifiers();
1095 Qualifiers ParamQs = Param.getQualifiers();
1096 DeducedQs.removeCVRQualifiers(ParamQs.getCVRQualifiers());
1097 if (ParamQs.hasObjCGCAttr())
1098 DeducedQs.removeObjCGCAttr();
1099 if (ParamQs.hasAddressSpace())
1100 DeducedQs.removeAddressSpace();
1101 if (ParamQs.hasObjCLifetime())
1102 DeducedQs.removeObjCLifetime();
1105 // If template deduction would produce a lifetime qualifier on a type
1106 // that is not a lifetime type, template argument deduction fails.
1107 if (ParamQs.hasObjCLifetime() && !DeducedType->isObjCLifetimeType() &&
1108 !DeducedType->isDependentType()) {
1109 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1110 Info.FirstArg = TemplateArgument(Param);
1111 Info.SecondArg = TemplateArgument(Arg);
1112 return Sema::TDK_Underqualified;
1116 // If template deduction would produce an argument type with lifetime type
1117 // but no lifetime qualifier, the __strong lifetime qualifier is inferred.
1118 if (S.getLangOpts().ObjCAutoRefCount &&
1119 DeducedType->isObjCLifetimeType() &&
1120 !DeducedQs.hasObjCLifetime())
1121 DeducedQs.setObjCLifetime(Qualifiers::OCL_Strong);
1123 DeducedType = S.Context.getQualifiedType(DeducedType.getUnqualifiedType(),
1126 if (RecanonicalizeArg)
1127 DeducedType = S.Context.getCanonicalType(DeducedType);
1129 DeducedTemplateArgument NewDeduced(DeducedType);
1130 DeducedTemplateArgument Result = checkDeducedTemplateArguments(S.Context,
1133 if (Result.isNull()) {
1134 Info.Param = cast<TemplateTypeParmDecl>(TemplateParams->getParam(Index));
1135 Info.FirstArg = Deduced[Index];
1136 Info.SecondArg = NewDeduced;
1137 return Sema::TDK_Inconsistent;
1140 Deduced[Index] = Result;
1141 return Sema::TDK_Success;
1144 // Set up the template argument deduction information for a failure.
1145 Info.FirstArg = TemplateArgument(ParamIn);
1146 Info.SecondArg = TemplateArgument(ArgIn);
1148 // If the parameter is an already-substituted template parameter
1149 // pack, do nothing: we don't know which of its arguments to look
1150 // at, so we have to wait until all of the parameter packs in this
1151 // expansion have arguments.
1152 if (isa<SubstTemplateTypeParmPackType>(Param))
1153 return Sema::TDK_Success;
1155 // Check the cv-qualifiers on the parameter and argument types.
1156 CanQualType CanParam = S.Context.getCanonicalType(Param);
1157 CanQualType CanArg = S.Context.getCanonicalType(Arg);
1158 if (!(TDF & TDF_IgnoreQualifiers)) {
1159 if (TDF & TDF_ParamWithReferenceType) {
1160 if (hasInconsistentOrSupersetQualifiersOf(Param, Arg))
1161 return Sema::TDK_NonDeducedMismatch;
1162 } else if (!IsPossiblyOpaquelyQualifiedType(Param)) {
1163 if (Param.getCVRQualifiers() != Arg.getCVRQualifiers())
1164 return Sema::TDK_NonDeducedMismatch;
1167 // If the parameter type is not dependent, there is nothing to deduce.
1168 if (!Param->isDependentType()) {
1169 if (!(TDF & TDF_SkipNonDependent)) {
1170 bool NonDeduced = (TDF & TDF_InOverloadResolution)?
1171 !S.isSameOrCompatibleFunctionType(CanParam, CanArg) :
1174 return Sema::TDK_NonDeducedMismatch;
1177 return Sema::TDK_Success;
1179 } else if (!Param->isDependentType()) {
1180 CanQualType ParamUnqualType = CanParam.getUnqualifiedType(),
1181 ArgUnqualType = CanArg.getUnqualifiedType();
1182 bool Success = (TDF & TDF_InOverloadResolution)?
1183 S.isSameOrCompatibleFunctionType(ParamUnqualType,
1185 ParamUnqualType == ArgUnqualType;
1187 return Sema::TDK_Success;
1190 switch (Param->getTypeClass()) {
1191 // Non-canonical types cannot appear here.
1192 #define NON_CANONICAL_TYPE(Class, Base) \
1193 case Type::Class: llvm_unreachable("deducing non-canonical type: " #Class);
1194 #define TYPE(Class, Base)
1195 #include "clang/AST/TypeNodes.def"
1197 case Type::TemplateTypeParm:
1198 case Type::SubstTemplateTypeParmPack:
1199 llvm_unreachable("Type nodes handled above");
1201 // These types cannot be dependent, so simply check whether the types are
1204 case Type::VariableArray:
1206 case Type::FunctionNoProto:
1209 case Type::ObjCObject:
1210 case Type::ObjCInterface:
1211 case Type::ObjCObjectPointer: {
1212 if (TDF & TDF_SkipNonDependent)
1213 return Sema::TDK_Success;
1215 if (TDF & TDF_IgnoreQualifiers) {
1216 Param = Param.getUnqualifiedType();
1217 Arg = Arg.getUnqualifiedType();
1220 return Param == Arg? Sema::TDK_Success : Sema::TDK_NonDeducedMismatch;
1223 // _Complex T [placeholder extension]
1225 if (const ComplexType *ComplexArg = Arg->getAs<ComplexType>())
1226 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1227 cast<ComplexType>(Param)->getElementType(),
1228 ComplexArg->getElementType(),
1229 Info, Deduced, TDF);
1231 return Sema::TDK_NonDeducedMismatch;
1233 // _Atomic T [extension]
1235 if (const AtomicType *AtomicArg = Arg->getAs<AtomicType>())
1236 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1237 cast<AtomicType>(Param)->getValueType(),
1238 AtomicArg->getValueType(),
1239 Info, Deduced, TDF);
1241 return Sema::TDK_NonDeducedMismatch;
1244 case Type::Pointer: {
1245 QualType PointeeType;
1246 if (const PointerType *PointerArg = Arg->getAs<PointerType>()) {
1247 PointeeType = PointerArg->getPointeeType();
1248 } else if (const ObjCObjectPointerType *PointerArg
1249 = Arg->getAs<ObjCObjectPointerType>()) {
1250 PointeeType = PointerArg->getPointeeType();
1252 return Sema::TDK_NonDeducedMismatch;
1255 unsigned SubTDF = TDF & (TDF_IgnoreQualifiers | TDF_DerivedClass);
1256 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1257 cast<PointerType>(Param)->getPointeeType(),
1259 Info, Deduced, SubTDF);
1263 case Type::LValueReference: {
1264 const LValueReferenceType *ReferenceArg =
1265 Arg->getAs<LValueReferenceType>();
1267 return Sema::TDK_NonDeducedMismatch;
1269 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1270 cast<LValueReferenceType>(Param)->getPointeeType(),
1271 ReferenceArg->getPointeeType(), Info, Deduced, 0);
1275 case Type::RValueReference: {
1276 const RValueReferenceType *ReferenceArg =
1277 Arg->getAs<RValueReferenceType>();
1279 return Sema::TDK_NonDeducedMismatch;
1281 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1282 cast<RValueReferenceType>(Param)->getPointeeType(),
1283 ReferenceArg->getPointeeType(),
1287 // T [] (implied, but not stated explicitly)
1288 case Type::IncompleteArray: {
1289 const IncompleteArrayType *IncompleteArrayArg =
1290 S.Context.getAsIncompleteArrayType(Arg);
1291 if (!IncompleteArrayArg)
1292 return Sema::TDK_NonDeducedMismatch;
1294 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1295 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1296 S.Context.getAsIncompleteArrayType(Param)->getElementType(),
1297 IncompleteArrayArg->getElementType(),
1298 Info, Deduced, SubTDF);
1301 // T [integer-constant]
1302 case Type::ConstantArray: {
1303 const ConstantArrayType *ConstantArrayArg =
1304 S.Context.getAsConstantArrayType(Arg);
1305 if (!ConstantArrayArg)
1306 return Sema::TDK_NonDeducedMismatch;
1308 const ConstantArrayType *ConstantArrayParm =
1309 S.Context.getAsConstantArrayType(Param);
1310 if (ConstantArrayArg->getSize() != ConstantArrayParm->getSize())
1311 return Sema::TDK_NonDeducedMismatch;
1313 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1314 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1315 ConstantArrayParm->getElementType(),
1316 ConstantArrayArg->getElementType(),
1317 Info, Deduced, SubTDF);
1321 case Type::DependentSizedArray: {
1322 const ArrayType *ArrayArg = S.Context.getAsArrayType(Arg);
1324 return Sema::TDK_NonDeducedMismatch;
1326 unsigned SubTDF = TDF & TDF_IgnoreQualifiers;
1328 // Check the element type of the arrays
1329 const DependentSizedArrayType *DependentArrayParm
1330 = S.Context.getAsDependentSizedArrayType(Param);
1331 if (Sema::TemplateDeductionResult Result
1332 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1333 DependentArrayParm->getElementType(),
1334 ArrayArg->getElementType(),
1335 Info, Deduced, SubTDF))
1338 // Determine the array bound is something we can deduce.
1339 NonTypeTemplateParmDecl *NTTP
1340 = getDeducedParameterFromExpr(DependentArrayParm->getSizeExpr());
1342 return Sema::TDK_Success;
1344 // We can perform template argument deduction for the given non-type
1345 // template parameter.
1346 assert(NTTP->getDepth() == 0 &&
1347 "Cannot deduce non-type template argument at depth > 0");
1348 if (const ConstantArrayType *ConstantArrayArg
1349 = dyn_cast<ConstantArrayType>(ArrayArg)) {
1350 llvm::APSInt Size(ConstantArrayArg->getSize());
1351 return DeduceNonTypeTemplateArgument(S, NTTP, Size,
1352 S.Context.getSizeType(),
1353 /*ArrayBound=*/true,
1356 if (const DependentSizedArrayType *DependentArrayArg
1357 = dyn_cast<DependentSizedArrayType>(ArrayArg))
1358 if (DependentArrayArg->getSizeExpr())
1359 return DeduceNonTypeTemplateArgument(S, NTTP,
1360 DependentArrayArg->getSizeExpr(),
1363 // Incomplete type does not match a dependently-sized array type
1364 return Sema::TDK_NonDeducedMismatch;
1370 case Type::FunctionProto: {
1371 unsigned SubTDF = TDF & TDF_TopLevelParameterTypeList;
1372 const FunctionProtoType *FunctionProtoArg =
1373 dyn_cast<FunctionProtoType>(Arg);
1374 if (!FunctionProtoArg)
1375 return Sema::TDK_NonDeducedMismatch;
1377 const FunctionProtoType *FunctionProtoParam =
1378 cast<FunctionProtoType>(Param);
1380 if (FunctionProtoParam->getTypeQuals()
1381 != FunctionProtoArg->getTypeQuals() ||
1382 FunctionProtoParam->getRefQualifier()
1383 != FunctionProtoArg->getRefQualifier() ||
1384 FunctionProtoParam->isVariadic() != FunctionProtoArg->isVariadic())
1385 return Sema::TDK_NonDeducedMismatch;
1387 // Check return types.
1388 if (Sema::TemplateDeductionResult Result =
1389 DeduceTemplateArgumentsByTypeMatch(
1390 S, TemplateParams, FunctionProtoParam->getReturnType(),
1391 FunctionProtoArg->getReturnType(), Info, Deduced, 0))
1394 return DeduceTemplateArguments(
1395 S, TemplateParams, FunctionProtoParam->param_type_begin(),
1396 FunctionProtoParam->getNumParams(),
1397 FunctionProtoArg->param_type_begin(),
1398 FunctionProtoArg->getNumParams(), Info, Deduced, SubTDF);
1401 case Type::InjectedClassName: {
1402 // Treat a template's injected-class-name as if the template
1403 // specialization type had been used.
1404 Param = cast<InjectedClassNameType>(Param)
1405 ->getInjectedSpecializationType();
1406 assert(isa<TemplateSpecializationType>(Param) &&
1407 "injected class name is not a template specialization type");
1411 // template-name<T> (where template-name refers to a class template)
1416 case Type::TemplateSpecialization: {
1417 const TemplateSpecializationType *SpecParam =
1418 cast<TemplateSpecializationType>(Param);
1420 // When Arg cannot be a derived class, we can just try to deduce template
1421 // arguments from the template-id.
1422 const RecordType *RecordT = Arg->getAs<RecordType>();
1423 if (!(TDF & TDF_DerivedClass) || !RecordT)
1424 return DeduceTemplateArguments(S, TemplateParams, SpecParam, Arg, Info,
1427 SmallVector<DeducedTemplateArgument, 8> DeducedOrig(Deduced.begin(),
1430 Sema::TemplateDeductionResult Result = DeduceTemplateArguments(
1431 S, TemplateParams, SpecParam, Arg, Info, Deduced);
1433 if (Result == Sema::TDK_Success)
1436 // We cannot inspect base classes as part of deduction when the type
1437 // is incomplete, so either instantiate any templates necessary to
1438 // complete the type, or skip over it if it cannot be completed.
1439 if (!S.isCompleteType(Info.getLocation(), Arg))
1442 // C++14 [temp.deduct.call] p4b3:
1443 // If P is a class and P has the form simple-template-id, then the
1444 // transformed A can be a derived class of the deduced A. Likewise if
1445 // P is a pointer to a class of the form simple-template-id, the
1446 // transformed A can be a pointer to a derived class pointed to by the
1449 // These alternatives are considered only if type deduction would
1450 // otherwise fail. If they yield more than one possible deduced A, the
1451 // type deduction fails.
1453 // Reset the incorrectly deduced argument from above.
1454 Deduced = DeducedOrig;
1456 // Use data recursion to crawl through the list of base classes.
1457 // Visited contains the set of nodes we have already visited, while
1458 // ToVisit is our stack of records that we still need to visit.
1459 llvm::SmallPtrSet<const RecordType *, 8> Visited;
1460 SmallVector<const RecordType *, 8> ToVisit;
1461 ToVisit.push_back(RecordT);
1462 bool Successful = false;
1463 SmallVector<DeducedTemplateArgument, 8> SuccessfulDeduced;
1464 while (!ToVisit.empty()) {
1465 // Retrieve the next class in the inheritance hierarchy.
1466 const RecordType *NextT = ToVisit.pop_back_val();
1468 // If we have already seen this type, skip it.
1469 if (!Visited.insert(NextT).second)
1472 // If this is a base class, try to perform template argument
1473 // deduction from it.
1474 if (NextT != RecordT) {
1475 TemplateDeductionInfo BaseInfo(Info.getLocation());
1476 Sema::TemplateDeductionResult BaseResult =
1477 DeduceTemplateArguments(S, TemplateParams, SpecParam,
1478 QualType(NextT, 0), BaseInfo, Deduced);
1480 // If template argument deduction for this base was successful,
1481 // note that we had some success. Otherwise, ignore any deductions
1482 // from this base class.
1483 if (BaseResult == Sema::TDK_Success) {
1484 // If we've already seen some success, then deduction fails due to
1485 // an ambiguity (temp.deduct.call p5).
1487 return Sema::TDK_MiscellaneousDeductionFailure;
1490 std::swap(SuccessfulDeduced, Deduced);
1492 Info.Param = BaseInfo.Param;
1493 Info.FirstArg = BaseInfo.FirstArg;
1494 Info.SecondArg = BaseInfo.SecondArg;
1497 Deduced = DeducedOrig;
1500 // Visit base classes
1501 CXXRecordDecl *Next = cast<CXXRecordDecl>(NextT->getDecl());
1502 for (const auto &Base : Next->bases()) {
1503 assert(Base.getType()->isRecordType() &&
1504 "Base class that isn't a record?");
1505 ToVisit.push_back(Base.getType()->getAs<RecordType>());
1510 std::swap(SuccessfulDeduced, Deduced);
1511 return Sema::TDK_Success;
1521 // type (type::*)(T)
1526 case Type::MemberPointer: {
1527 const MemberPointerType *MemPtrParam = cast<MemberPointerType>(Param);
1528 const MemberPointerType *MemPtrArg = dyn_cast<MemberPointerType>(Arg);
1530 return Sema::TDK_NonDeducedMismatch;
1532 QualType ParamPointeeType = MemPtrParam->getPointeeType();
1533 if (ParamPointeeType->isFunctionType())
1534 S.adjustMemberFunctionCC(ParamPointeeType, /*IsStatic=*/true,
1535 /*IsCtorOrDtor=*/false, Info.getLocation());
1536 QualType ArgPointeeType = MemPtrArg->getPointeeType();
1537 if (ArgPointeeType->isFunctionType())
1538 S.adjustMemberFunctionCC(ArgPointeeType, /*IsStatic=*/true,
1539 /*IsCtorOrDtor=*/false, Info.getLocation());
1541 if (Sema::TemplateDeductionResult Result
1542 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1546 TDF & TDF_IgnoreQualifiers))
1549 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1550 QualType(MemPtrParam->getClass(), 0),
1551 QualType(MemPtrArg->getClass(), 0),
1553 TDF & TDF_IgnoreQualifiers);
1556 // (clang extension)
1561 case Type::BlockPointer: {
1562 const BlockPointerType *BlockPtrParam = cast<BlockPointerType>(Param);
1563 const BlockPointerType *BlockPtrArg = dyn_cast<BlockPointerType>(Arg);
1566 return Sema::TDK_NonDeducedMismatch;
1568 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1569 BlockPtrParam->getPointeeType(),
1570 BlockPtrArg->getPointeeType(),
1574 // (clang extension)
1576 // T __attribute__(((ext_vector_type(<integral constant>))))
1577 case Type::ExtVector: {
1578 const ExtVectorType *VectorParam = cast<ExtVectorType>(Param);
1579 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
1580 // Make sure that the vectors have the same number of elements.
1581 if (VectorParam->getNumElements() != VectorArg->getNumElements())
1582 return Sema::TDK_NonDeducedMismatch;
1584 // Perform deduction on the element types.
1585 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1586 VectorParam->getElementType(),
1587 VectorArg->getElementType(),
1588 Info, Deduced, TDF);
1591 if (const DependentSizedExtVectorType *VectorArg
1592 = dyn_cast<DependentSizedExtVectorType>(Arg)) {
1593 // We can't check the number of elements, since the argument has a
1594 // dependent number of elements. This can only occur during partial
1597 // Perform deduction on the element types.
1598 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1599 VectorParam->getElementType(),
1600 VectorArg->getElementType(),
1601 Info, Deduced, TDF);
1604 return Sema::TDK_NonDeducedMismatch;
1607 // (clang extension)
1609 // T __attribute__(((ext_vector_type(N))))
1610 case Type::DependentSizedExtVector: {
1611 const DependentSizedExtVectorType *VectorParam
1612 = cast<DependentSizedExtVectorType>(Param);
1614 if (const ExtVectorType *VectorArg = dyn_cast<ExtVectorType>(Arg)) {
1615 // Perform deduction on the element types.
1616 if (Sema::TemplateDeductionResult Result
1617 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1618 VectorParam->getElementType(),
1619 VectorArg->getElementType(),
1620 Info, Deduced, TDF))
1623 // Perform deduction on the vector size, if we can.
1624 NonTypeTemplateParmDecl *NTTP
1625 = getDeducedParameterFromExpr(VectorParam->getSizeExpr());
1627 return Sema::TDK_Success;
1629 llvm::APSInt ArgSize(S.Context.getTypeSize(S.Context.IntTy), false);
1630 ArgSize = VectorArg->getNumElements();
1631 return DeduceNonTypeTemplateArgument(S, NTTP, ArgSize, S.Context.IntTy,
1632 false, Info, Deduced);
1635 if (const DependentSizedExtVectorType *VectorArg
1636 = dyn_cast<DependentSizedExtVectorType>(Arg)) {
1637 // Perform deduction on the element types.
1638 if (Sema::TemplateDeductionResult Result
1639 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1640 VectorParam->getElementType(),
1641 VectorArg->getElementType(),
1642 Info, Deduced, TDF))
1645 // Perform deduction on the vector size, if we can.
1646 NonTypeTemplateParmDecl *NTTP
1647 = getDeducedParameterFromExpr(VectorParam->getSizeExpr());
1649 return Sema::TDK_Success;
1651 return DeduceNonTypeTemplateArgument(S, NTTP, VectorArg->getSizeExpr(),
1655 return Sema::TDK_NonDeducedMismatch;
1658 case Type::TypeOfExpr:
1660 case Type::DependentName:
1661 case Type::UnresolvedUsing:
1662 case Type::Decltype:
1663 case Type::UnaryTransform:
1665 case Type::DependentTemplateSpecialization:
1666 case Type::PackExpansion:
1668 // No template argument deduction for these types
1669 return Sema::TDK_Success;
1672 llvm_unreachable("Invalid Type Class!");
1675 static Sema::TemplateDeductionResult
1676 DeduceTemplateArguments(Sema &S,
1677 TemplateParameterList *TemplateParams,
1678 const TemplateArgument &Param,
1679 TemplateArgument Arg,
1680 TemplateDeductionInfo &Info,
1681 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
1682 // If the template argument is a pack expansion, perform template argument
1683 // deduction against the pattern of that expansion. This only occurs during
1684 // partial ordering.
1685 if (Arg.isPackExpansion())
1686 Arg = Arg.getPackExpansionPattern();
1688 switch (Param.getKind()) {
1689 case TemplateArgument::Null:
1690 llvm_unreachable("Null template argument in parameter list");
1692 case TemplateArgument::Type:
1693 if (Arg.getKind() == TemplateArgument::Type)
1694 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
1698 Info.FirstArg = Param;
1699 Info.SecondArg = Arg;
1700 return Sema::TDK_NonDeducedMismatch;
1702 case TemplateArgument::Template:
1703 if (Arg.getKind() == TemplateArgument::Template)
1704 return DeduceTemplateArguments(S, TemplateParams,
1705 Param.getAsTemplate(),
1706 Arg.getAsTemplate(), Info, Deduced);
1707 Info.FirstArg = Param;
1708 Info.SecondArg = Arg;
1709 return Sema::TDK_NonDeducedMismatch;
1711 case TemplateArgument::TemplateExpansion:
1712 llvm_unreachable("caller should handle pack expansions");
1714 case TemplateArgument::Declaration:
1715 if (Arg.getKind() == TemplateArgument::Declaration &&
1716 isSameDeclaration(Param.getAsDecl(), Arg.getAsDecl()))
1717 return Sema::TDK_Success;
1719 Info.FirstArg = Param;
1720 Info.SecondArg = Arg;
1721 return Sema::TDK_NonDeducedMismatch;
1723 case TemplateArgument::NullPtr:
1724 if (Arg.getKind() == TemplateArgument::NullPtr &&
1725 S.Context.hasSameType(Param.getNullPtrType(), Arg.getNullPtrType()))
1726 return Sema::TDK_Success;
1728 Info.FirstArg = Param;
1729 Info.SecondArg = Arg;
1730 return Sema::TDK_NonDeducedMismatch;
1732 case TemplateArgument::Integral:
1733 if (Arg.getKind() == TemplateArgument::Integral) {
1734 if (hasSameExtendedValue(Param.getAsIntegral(), Arg.getAsIntegral()))
1735 return Sema::TDK_Success;
1737 Info.FirstArg = Param;
1738 Info.SecondArg = Arg;
1739 return Sema::TDK_NonDeducedMismatch;
1742 if (Arg.getKind() == TemplateArgument::Expression) {
1743 Info.FirstArg = Param;
1744 Info.SecondArg = Arg;
1745 return Sema::TDK_NonDeducedMismatch;
1748 Info.FirstArg = Param;
1749 Info.SecondArg = Arg;
1750 return Sema::TDK_NonDeducedMismatch;
1752 case TemplateArgument::Expression: {
1753 if (NonTypeTemplateParmDecl *NTTP
1754 = getDeducedParameterFromExpr(Param.getAsExpr())) {
1755 if (Arg.getKind() == TemplateArgument::Integral)
1756 return DeduceNonTypeTemplateArgument(S, NTTP,
1757 Arg.getAsIntegral(),
1758 Arg.getIntegralType(),
1759 /*ArrayBound=*/false,
1761 if (Arg.getKind() == TemplateArgument::Expression)
1762 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsExpr(),
1764 if (Arg.getKind() == TemplateArgument::Declaration)
1765 return DeduceNonTypeTemplateArgument(S, NTTP, Arg.getAsDecl(),
1768 Info.FirstArg = Param;
1769 Info.SecondArg = Arg;
1770 return Sema::TDK_NonDeducedMismatch;
1773 // Can't deduce anything, but that's okay.
1774 return Sema::TDK_Success;
1776 case TemplateArgument::Pack:
1777 llvm_unreachable("Argument packs should be expanded by the caller!");
1780 llvm_unreachable("Invalid TemplateArgument Kind!");
1783 /// \brief Determine whether there is a template argument to be used for
1786 /// This routine "expands" argument packs in-place, overriding its input
1787 /// parameters so that \c Args[ArgIdx] will be the available template argument.
1789 /// \returns true if there is another template argument (which will be at
1790 /// \c Args[ArgIdx]), false otherwise.
1791 static bool hasTemplateArgumentForDeduction(const TemplateArgument *&Args,
1793 unsigned &NumArgs) {
1794 if (ArgIdx == NumArgs)
1797 const TemplateArgument &Arg = Args[ArgIdx];
1798 if (Arg.getKind() != TemplateArgument::Pack)
1801 assert(ArgIdx == NumArgs - 1 && "Pack not at the end of argument list?");
1802 Args = Arg.pack_begin();
1803 NumArgs = Arg.pack_size();
1805 return ArgIdx < NumArgs;
1808 /// \brief Determine whether the given set of template arguments has a pack
1809 /// expansion that is not the last template argument.
1810 static bool hasPackExpansionBeforeEnd(const TemplateArgument *Args,
1812 unsigned ArgIdx = 0;
1813 while (ArgIdx < NumArgs) {
1814 const TemplateArgument &Arg = Args[ArgIdx];
1816 // Unwrap argument packs.
1817 if (Args[ArgIdx].getKind() == TemplateArgument::Pack) {
1818 Args = Arg.pack_begin();
1819 NumArgs = Arg.pack_size();
1825 if (ArgIdx == NumArgs)
1828 if (Arg.isPackExpansion())
1835 static Sema::TemplateDeductionResult
1836 DeduceTemplateArguments(Sema &S, TemplateParameterList *TemplateParams,
1837 const TemplateArgument *Params, unsigned NumParams,
1838 const TemplateArgument *Args, unsigned NumArgs,
1839 TemplateDeductionInfo &Info,
1840 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
1841 bool NumberOfArgumentsMustMatch) {
1842 // C++0x [temp.deduct.type]p9:
1843 // If the template argument list of P contains a pack expansion that is not
1844 // the last template argument, the entire template argument list is a
1845 // non-deduced context.
1846 if (hasPackExpansionBeforeEnd(Params, NumParams))
1847 return Sema::TDK_Success;
1849 // C++0x [temp.deduct.type]p9:
1850 // If P has a form that contains <T> or <i>, then each argument Pi of the
1851 // respective template argument list P is compared with the corresponding
1852 // argument Ai of the corresponding template argument list of A.
1853 unsigned ArgIdx = 0, ParamIdx = 0;
1854 for (; hasTemplateArgumentForDeduction(Params, ParamIdx, NumParams);
1856 if (!Params[ParamIdx].isPackExpansion()) {
1857 // The simple case: deduce template arguments by matching Pi and Ai.
1859 // Check whether we have enough arguments.
1860 if (!hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs))
1861 return NumberOfArgumentsMustMatch ? Sema::TDK_TooFewArguments
1862 : Sema::TDK_Success;
1864 if (Args[ArgIdx].isPackExpansion()) {
1865 // FIXME: We follow the logic of C++0x [temp.deduct.type]p22 here,
1866 // but applied to pack expansions that are template arguments.
1867 return Sema::TDK_MiscellaneousDeductionFailure;
1870 // Perform deduction for this Pi/Ai pair.
1871 if (Sema::TemplateDeductionResult Result
1872 = DeduceTemplateArguments(S, TemplateParams,
1873 Params[ParamIdx], Args[ArgIdx],
1877 // Move to the next argument.
1882 // The parameter is a pack expansion.
1884 // C++0x [temp.deduct.type]p9:
1885 // If Pi is a pack expansion, then the pattern of Pi is compared with
1886 // each remaining argument in the template argument list of A. Each
1887 // comparison deduces template arguments for subsequent positions in the
1888 // template parameter packs expanded by Pi.
1889 TemplateArgument Pattern = Params[ParamIdx].getPackExpansionPattern();
1891 // FIXME: If there are no remaining arguments, we can bail out early
1892 // and set any deduced parameter packs to an empty argument pack.
1893 // The latter part of this is a (minor) correctness issue.
1895 // Prepare to deduce the packs within the pattern.
1896 PackDeductionScope PackScope(S, TemplateParams, Deduced, Info, Pattern);
1898 // Keep track of the deduced template arguments for each parameter pack
1899 // expanded by this pack expansion (the outer index) and for each
1900 // template argument (the inner SmallVectors).
1901 bool HasAnyArguments = false;
1902 for (; hasTemplateArgumentForDeduction(Args, ArgIdx, NumArgs); ++ArgIdx) {
1903 HasAnyArguments = true;
1905 // Deduce template arguments from the pattern.
1906 if (Sema::TemplateDeductionResult Result
1907 = DeduceTemplateArguments(S, TemplateParams, Pattern, Args[ArgIdx],
1911 PackScope.nextPackElement();
1914 // Build argument packs for each of the parameter packs expanded by this
1916 if (auto Result = PackScope.finish(HasAnyArguments))
1920 return Sema::TDK_Success;
1923 static Sema::TemplateDeductionResult
1924 DeduceTemplateArguments(Sema &S,
1925 TemplateParameterList *TemplateParams,
1926 const TemplateArgumentList &ParamList,
1927 const TemplateArgumentList &ArgList,
1928 TemplateDeductionInfo &Info,
1929 SmallVectorImpl<DeducedTemplateArgument> &Deduced) {
1930 return DeduceTemplateArguments(S, TemplateParams,
1931 ParamList.data(), ParamList.size(),
1932 ArgList.data(), ArgList.size(),
1933 Info, Deduced, false);
1936 /// \brief Determine whether two template arguments are the same.
1937 static bool isSameTemplateArg(ASTContext &Context,
1938 const TemplateArgument &X,
1939 const TemplateArgument &Y) {
1940 if (X.getKind() != Y.getKind())
1943 switch (X.getKind()) {
1944 case TemplateArgument::Null:
1945 llvm_unreachable("Comparing NULL template argument");
1947 case TemplateArgument::Type:
1948 return Context.getCanonicalType(X.getAsType()) ==
1949 Context.getCanonicalType(Y.getAsType());
1951 case TemplateArgument::Declaration:
1952 return isSameDeclaration(X.getAsDecl(), Y.getAsDecl());
1954 case TemplateArgument::NullPtr:
1955 return Context.hasSameType(X.getNullPtrType(), Y.getNullPtrType());
1957 case TemplateArgument::Template:
1958 case TemplateArgument::TemplateExpansion:
1959 return Context.getCanonicalTemplateName(
1960 X.getAsTemplateOrTemplatePattern()).getAsVoidPointer() ==
1961 Context.getCanonicalTemplateName(
1962 Y.getAsTemplateOrTemplatePattern()).getAsVoidPointer();
1964 case TemplateArgument::Integral:
1965 return X.getAsIntegral() == Y.getAsIntegral();
1967 case TemplateArgument::Expression: {
1968 llvm::FoldingSetNodeID XID, YID;
1969 X.getAsExpr()->Profile(XID, Context, true);
1970 Y.getAsExpr()->Profile(YID, Context, true);
1974 case TemplateArgument::Pack:
1975 if (X.pack_size() != Y.pack_size())
1978 for (TemplateArgument::pack_iterator XP = X.pack_begin(),
1979 XPEnd = X.pack_end(),
1980 YP = Y.pack_begin();
1981 XP != XPEnd; ++XP, ++YP)
1982 if (!isSameTemplateArg(Context, *XP, *YP))
1988 llvm_unreachable("Invalid TemplateArgument Kind!");
1991 /// \brief Allocate a TemplateArgumentLoc where all locations have
1992 /// been initialized to the given location.
1994 /// \param S The semantic analysis object.
1996 /// \param Arg The template argument we are producing template argument
1997 /// location information for.
1999 /// \param NTTPType For a declaration template argument, the type of
2000 /// the non-type template parameter that corresponds to this template
2003 /// \param Loc The source location to use for the resulting template
2005 static TemplateArgumentLoc
2006 getTrivialTemplateArgumentLoc(Sema &S,
2007 const TemplateArgument &Arg,
2009 SourceLocation Loc) {
2010 switch (Arg.getKind()) {
2011 case TemplateArgument::Null:
2012 llvm_unreachable("Can't get a NULL template argument here");
2014 case TemplateArgument::Type:
2015 return TemplateArgumentLoc(Arg,
2016 S.Context.getTrivialTypeSourceInfo(Arg.getAsType(), Loc));
2018 case TemplateArgument::Declaration: {
2020 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
2022 return TemplateArgumentLoc(TemplateArgument(E), E);
2025 case TemplateArgument::NullPtr: {
2027 = S.BuildExpressionFromDeclTemplateArgument(Arg, NTTPType, Loc)
2029 return TemplateArgumentLoc(TemplateArgument(NTTPType, /*isNullPtr*/true),
2033 case TemplateArgument::Integral: {
2035 = S.BuildExpressionFromIntegralTemplateArgument(Arg, Loc).getAs<Expr>();
2036 return TemplateArgumentLoc(TemplateArgument(E), E);
2039 case TemplateArgument::Template:
2040 case TemplateArgument::TemplateExpansion: {
2041 NestedNameSpecifierLocBuilder Builder;
2042 TemplateName Template = Arg.getAsTemplate();
2043 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName())
2044 Builder.MakeTrivial(S.Context, DTN->getQualifier(), Loc);
2045 else if (QualifiedTemplateName *QTN =
2046 Template.getAsQualifiedTemplateName())
2047 Builder.MakeTrivial(S.Context, QTN->getQualifier(), Loc);
2049 if (Arg.getKind() == TemplateArgument::Template)
2050 return TemplateArgumentLoc(Arg,
2051 Builder.getWithLocInContext(S.Context),
2055 return TemplateArgumentLoc(Arg, Builder.getWithLocInContext(S.Context),
2059 case TemplateArgument::Expression:
2060 return TemplateArgumentLoc(Arg, Arg.getAsExpr());
2062 case TemplateArgument::Pack:
2063 return TemplateArgumentLoc(Arg, TemplateArgumentLocInfo());
2066 llvm_unreachable("Invalid TemplateArgument Kind!");
2070 /// \brief Convert the given deduced template argument and add it to the set of
2071 /// fully-converted template arguments.
2073 ConvertDeducedTemplateArgument(Sema &S, NamedDecl *Param,
2074 DeducedTemplateArgument Arg,
2075 NamedDecl *Template,
2076 TemplateDeductionInfo &Info,
2077 bool InFunctionTemplate,
2078 SmallVectorImpl<TemplateArgument> &Output) {
2079 // First, for a non-type template parameter type that is
2080 // initialized by a declaration, we need the type of the
2081 // corresponding non-type template parameter.
2083 if (NonTypeTemplateParmDecl *NTTP =
2084 dyn_cast<NonTypeTemplateParmDecl>(Param)) {
2085 NTTPType = NTTP->getType();
2086 if (NTTPType->isDependentType()) {
2087 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Output);
2088 NTTPType = S.SubstType(NTTPType,
2089 MultiLevelTemplateArgumentList(TemplateArgs),
2090 NTTP->getLocation(),
2091 NTTP->getDeclName());
2092 if (NTTPType.isNull())
2097 auto ConvertArg = [&](DeducedTemplateArgument Arg,
2098 unsigned ArgumentPackIndex) {
2099 // Convert the deduced template argument into a template
2100 // argument that we can check, almost as if the user had written
2101 // the template argument explicitly.
2102 TemplateArgumentLoc ArgLoc =
2103 getTrivialTemplateArgumentLoc(S, Arg, NTTPType, Info.getLocation());
2105 // Check the template argument, converting it as necessary.
2106 return S.CheckTemplateArgument(
2107 Param, ArgLoc, Template, Template->getLocation(),
2108 Template->getSourceRange().getEnd(), ArgumentPackIndex, Output,
2110 ? (Arg.wasDeducedFromArrayBound() ? Sema::CTAK_DeducedFromArrayBound
2111 : Sema::CTAK_Deduced)
2112 : Sema::CTAK_Specified);
2115 if (Arg.getKind() == TemplateArgument::Pack) {
2116 // This is a template argument pack, so check each of its arguments against
2117 // the template parameter.
2118 SmallVector<TemplateArgument, 2> PackedArgsBuilder;
2119 for (const auto &P : Arg.pack_elements()) {
2120 // When converting the deduced template argument, append it to the
2121 // general output list. We need to do this so that the template argument
2122 // checking logic has all of the prior template arguments available.
2123 DeducedTemplateArgument InnerArg(P);
2124 InnerArg.setDeducedFromArrayBound(Arg.wasDeducedFromArrayBound());
2125 assert(InnerArg.getKind() != TemplateArgument::Pack &&
2126 "deduced nested pack");
2127 if (ConvertArg(InnerArg, PackedArgsBuilder.size()))
2130 // Move the converted template argument into our argument pack.
2131 PackedArgsBuilder.push_back(Output.pop_back_val());
2134 // If the pack is empty, we still need to substitute into the parameter
2135 // itself, in case that substitution fails. For non-type parameters, we did
2136 // this above. For type parameters, no substitution is ever required.
2137 auto *TTP = dyn_cast<TemplateTemplateParmDecl>(Param);
2138 if (TTP && PackedArgsBuilder.empty()) {
2139 // Set up a template instantiation context.
2140 LocalInstantiationScope Scope(S);
2141 Sema::InstantiatingTemplate Inst(S, Template->getLocation(), Template,
2143 Template->getSourceRange());
2144 if (Inst.isInvalid())
2147 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Output);
2148 if (!S.SubstDecl(TTP, S.CurContext,
2149 MultiLevelTemplateArgumentList(TemplateArgs)))
2153 // Create the resulting argument pack.
2155 TemplateArgument::CreatePackCopy(S.Context, PackedArgsBuilder));
2159 return ConvertArg(Arg, 0);
2162 /// Complete template argument deduction for a class template partial
2164 static Sema::TemplateDeductionResult
2165 FinishTemplateArgumentDeduction(Sema &S,
2166 ClassTemplatePartialSpecializationDecl *Partial,
2167 const TemplateArgumentList &TemplateArgs,
2168 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2169 TemplateDeductionInfo &Info) {
2170 // Unevaluated SFINAE context.
2171 EnterExpressionEvaluationContext Unevaluated(S, Sema::Unevaluated);
2172 Sema::SFINAETrap Trap(S);
2174 Sema::ContextRAII SavedContext(S, Partial);
2176 // C++ [temp.deduct.type]p2:
2177 // [...] or if any template argument remains neither deduced nor
2178 // explicitly specified, template argument deduction fails.
2179 SmallVector<TemplateArgument, 4> Builder;
2180 TemplateParameterList *PartialParams = Partial->getTemplateParameters();
2181 for (unsigned I = 0, N = PartialParams->size(); I != N; ++I) {
2182 NamedDecl *Param = PartialParams->getParam(I);
2183 if (Deduced[I].isNull()) {
2184 Info.Param = makeTemplateParameter(Param);
2185 return Sema::TDK_Incomplete;
2188 // We have deduced this argument, so it still needs to be
2189 // checked and converted.
2190 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I],
2191 Partial, Info, false,
2193 Info.Param = makeTemplateParameter(Param);
2194 // FIXME: These template arguments are temporary. Free them!
2195 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2196 return Sema::TDK_SubstitutionFailure;
2200 // Form the template argument list from the deduced template arguments.
2201 TemplateArgumentList *DeducedArgumentList
2202 = TemplateArgumentList::CreateCopy(S.Context, Builder);
2204 Info.reset(DeducedArgumentList);
2206 // Substitute the deduced template arguments into the template
2207 // arguments of the class template partial specialization, and
2208 // verify that the instantiated template arguments are both valid
2209 // and are equivalent to the template arguments originally provided
2210 // to the class template.
2211 LocalInstantiationScope InstScope(S);
2212 ClassTemplateDecl *ClassTemplate = Partial->getSpecializedTemplate();
2213 const ASTTemplateArgumentListInfo *PartialTemplArgInfo
2214 = Partial->getTemplateArgsAsWritten();
2215 const TemplateArgumentLoc *PartialTemplateArgs
2216 = PartialTemplArgInfo->getTemplateArgs();
2218 TemplateArgumentListInfo InstArgs(PartialTemplArgInfo->LAngleLoc,
2219 PartialTemplArgInfo->RAngleLoc);
2221 if (S.Subst(PartialTemplateArgs, PartialTemplArgInfo->NumTemplateArgs,
2222 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) {
2223 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx;
2224 if (ParamIdx >= Partial->getTemplateParameters()->size())
2225 ParamIdx = Partial->getTemplateParameters()->size() - 1;
2228 = const_cast<NamedDecl *>(
2229 Partial->getTemplateParameters()->getParam(ParamIdx));
2230 Info.Param = makeTemplateParameter(Param);
2231 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument();
2232 return Sema::TDK_SubstitutionFailure;
2235 SmallVector<TemplateArgument, 4> ConvertedInstArgs;
2236 if (S.CheckTemplateArgumentList(ClassTemplate, Partial->getLocation(),
2237 InstArgs, false, ConvertedInstArgs))
2238 return Sema::TDK_SubstitutionFailure;
2240 TemplateParameterList *TemplateParams
2241 = ClassTemplate->getTemplateParameters();
2242 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
2243 TemplateArgument InstArg = ConvertedInstArgs.data()[I];
2244 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) {
2245 Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
2246 Info.FirstArg = TemplateArgs[I];
2247 Info.SecondArg = InstArg;
2248 return Sema::TDK_NonDeducedMismatch;
2252 if (Trap.hasErrorOccurred())
2253 return Sema::TDK_SubstitutionFailure;
2255 return Sema::TDK_Success;
2258 /// \brief Perform template argument deduction to determine whether
2259 /// the given template arguments match the given class template
2260 /// partial specialization per C++ [temp.class.spec.match].
2261 Sema::TemplateDeductionResult
2262 Sema::DeduceTemplateArguments(ClassTemplatePartialSpecializationDecl *Partial,
2263 const TemplateArgumentList &TemplateArgs,
2264 TemplateDeductionInfo &Info) {
2265 if (Partial->isInvalidDecl())
2268 // C++ [temp.class.spec.match]p2:
2269 // A partial specialization matches a given actual template
2270 // argument list if the template arguments of the partial
2271 // specialization can be deduced from the actual template argument
2274 // Unevaluated SFINAE context.
2275 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
2276 SFINAETrap Trap(*this);
2278 SmallVector<DeducedTemplateArgument, 4> Deduced;
2279 Deduced.resize(Partial->getTemplateParameters()->size());
2280 if (TemplateDeductionResult Result
2281 = ::DeduceTemplateArguments(*this,
2282 Partial->getTemplateParameters(),
2283 Partial->getTemplateArgs(),
2284 TemplateArgs, Info, Deduced))
2287 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
2288 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
2290 if (Inst.isInvalid())
2291 return TDK_InstantiationDepth;
2293 if (Trap.hasErrorOccurred())
2294 return Sema::TDK_SubstitutionFailure;
2296 return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs,
2300 /// Complete template argument deduction for a variable template partial
2302 /// TODO: Unify with ClassTemplatePartialSpecializationDecl version?
2303 /// May require unifying ClassTemplate(Partial)SpecializationDecl and
2304 /// VarTemplate(Partial)SpecializationDecl with a new data
2305 /// structure Template(Partial)SpecializationDecl, and
2306 /// using Template(Partial)SpecializationDecl as input type.
2307 static Sema::TemplateDeductionResult FinishTemplateArgumentDeduction(
2308 Sema &S, VarTemplatePartialSpecializationDecl *Partial,
2309 const TemplateArgumentList &TemplateArgs,
2310 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2311 TemplateDeductionInfo &Info) {
2312 // Unevaluated SFINAE context.
2313 EnterExpressionEvaluationContext Unevaluated(S, Sema::Unevaluated);
2314 Sema::SFINAETrap Trap(S);
2316 // C++ [temp.deduct.type]p2:
2317 // [...] or if any template argument remains neither deduced nor
2318 // explicitly specified, template argument deduction fails.
2319 SmallVector<TemplateArgument, 4> Builder;
2320 TemplateParameterList *PartialParams = Partial->getTemplateParameters();
2321 for (unsigned I = 0, N = PartialParams->size(); I != N; ++I) {
2322 NamedDecl *Param = PartialParams->getParam(I);
2323 if (Deduced[I].isNull()) {
2324 Info.Param = makeTemplateParameter(Param);
2325 return Sema::TDK_Incomplete;
2328 // We have deduced this argument, so it still needs to be
2329 // checked and converted.
2330 if (ConvertDeducedTemplateArgument(S, Param, Deduced[I], Partial,
2331 Info, false, Builder)) {
2332 Info.Param = makeTemplateParameter(Param);
2333 // FIXME: These template arguments are temporary. Free them!
2334 Info.reset(TemplateArgumentList::CreateCopy(S.Context, Builder));
2335 return Sema::TDK_SubstitutionFailure;
2339 // Form the template argument list from the deduced template arguments.
2340 TemplateArgumentList *DeducedArgumentList = TemplateArgumentList::CreateCopy(
2341 S.Context, Builder);
2343 Info.reset(DeducedArgumentList);
2345 // Substitute the deduced template arguments into the template
2346 // arguments of the class template partial specialization, and
2347 // verify that the instantiated template arguments are both valid
2348 // and are equivalent to the template arguments originally provided
2349 // to the class template.
2350 LocalInstantiationScope InstScope(S);
2351 VarTemplateDecl *VarTemplate = Partial->getSpecializedTemplate();
2352 const ASTTemplateArgumentListInfo *PartialTemplArgInfo
2353 = Partial->getTemplateArgsAsWritten();
2354 const TemplateArgumentLoc *PartialTemplateArgs
2355 = PartialTemplArgInfo->getTemplateArgs();
2357 TemplateArgumentListInfo InstArgs(PartialTemplArgInfo->LAngleLoc,
2358 PartialTemplArgInfo->RAngleLoc);
2360 if (S.Subst(PartialTemplateArgs, PartialTemplArgInfo->NumTemplateArgs,
2361 InstArgs, MultiLevelTemplateArgumentList(*DeducedArgumentList))) {
2362 unsigned ArgIdx = InstArgs.size(), ParamIdx = ArgIdx;
2363 if (ParamIdx >= Partial->getTemplateParameters()->size())
2364 ParamIdx = Partial->getTemplateParameters()->size() - 1;
2366 Decl *Param = const_cast<NamedDecl *>(
2367 Partial->getTemplateParameters()->getParam(ParamIdx));
2368 Info.Param = makeTemplateParameter(Param);
2369 Info.FirstArg = PartialTemplateArgs[ArgIdx].getArgument();
2370 return Sema::TDK_SubstitutionFailure;
2372 SmallVector<TemplateArgument, 4> ConvertedInstArgs;
2373 if (S.CheckTemplateArgumentList(VarTemplate, Partial->getLocation(), InstArgs,
2374 false, ConvertedInstArgs))
2375 return Sema::TDK_SubstitutionFailure;
2377 TemplateParameterList *TemplateParams = VarTemplate->getTemplateParameters();
2378 for (unsigned I = 0, E = TemplateParams->size(); I != E; ++I) {
2379 TemplateArgument InstArg = ConvertedInstArgs.data()[I];
2380 if (!isSameTemplateArg(S.Context, TemplateArgs[I], InstArg)) {
2381 Info.Param = makeTemplateParameter(TemplateParams->getParam(I));
2382 Info.FirstArg = TemplateArgs[I];
2383 Info.SecondArg = InstArg;
2384 return Sema::TDK_NonDeducedMismatch;
2388 if (Trap.hasErrorOccurred())
2389 return Sema::TDK_SubstitutionFailure;
2391 return Sema::TDK_Success;
2394 /// \brief Perform template argument deduction to determine whether
2395 /// the given template arguments match the given variable template
2396 /// partial specialization per C++ [temp.class.spec.match].
2397 /// TODO: Unify with ClassTemplatePartialSpecializationDecl version?
2398 /// May require unifying ClassTemplate(Partial)SpecializationDecl and
2399 /// VarTemplate(Partial)SpecializationDecl with a new data
2400 /// structure Template(Partial)SpecializationDecl, and
2401 /// using Template(Partial)SpecializationDecl as input type.
2402 Sema::TemplateDeductionResult
2403 Sema::DeduceTemplateArguments(VarTemplatePartialSpecializationDecl *Partial,
2404 const TemplateArgumentList &TemplateArgs,
2405 TemplateDeductionInfo &Info) {
2406 if (Partial->isInvalidDecl())
2409 // C++ [temp.class.spec.match]p2:
2410 // A partial specialization matches a given actual template
2411 // argument list if the template arguments of the partial
2412 // specialization can be deduced from the actual template argument
2415 // Unevaluated SFINAE context.
2416 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
2417 SFINAETrap Trap(*this);
2419 SmallVector<DeducedTemplateArgument, 4> Deduced;
2420 Deduced.resize(Partial->getTemplateParameters()->size());
2421 if (TemplateDeductionResult Result = ::DeduceTemplateArguments(
2422 *this, Partial->getTemplateParameters(), Partial->getTemplateArgs(),
2423 TemplateArgs, Info, Deduced))
2426 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
2427 InstantiatingTemplate Inst(*this, Info.getLocation(), Partial, DeducedArgs,
2429 if (Inst.isInvalid())
2430 return TDK_InstantiationDepth;
2432 if (Trap.hasErrorOccurred())
2433 return Sema::TDK_SubstitutionFailure;
2435 return ::FinishTemplateArgumentDeduction(*this, Partial, TemplateArgs,
2439 /// \brief Determine whether the given type T is a simple-template-id type.
2440 static bool isSimpleTemplateIdType(QualType T) {
2441 if (const TemplateSpecializationType *Spec
2442 = T->getAs<TemplateSpecializationType>())
2443 return Spec->getTemplateName().getAsTemplateDecl() != nullptr;
2448 /// \brief Substitute the explicitly-provided template arguments into the
2449 /// given function template according to C++ [temp.arg.explicit].
2451 /// \param FunctionTemplate the function template into which the explicit
2452 /// template arguments will be substituted.
2454 /// \param ExplicitTemplateArgs the explicitly-specified template
2457 /// \param Deduced the deduced template arguments, which will be populated
2458 /// with the converted and checked explicit template arguments.
2460 /// \param ParamTypes will be populated with the instantiated function
2463 /// \param FunctionType if non-NULL, the result type of the function template
2464 /// will also be instantiated and the pointed-to value will be updated with
2465 /// the instantiated function type.
2467 /// \param Info if substitution fails for any reason, this object will be
2468 /// populated with more information about the failure.
2470 /// \returns TDK_Success if substitution was successful, or some failure
2472 Sema::TemplateDeductionResult
2473 Sema::SubstituteExplicitTemplateArguments(
2474 FunctionTemplateDecl *FunctionTemplate,
2475 TemplateArgumentListInfo &ExplicitTemplateArgs,
2476 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2477 SmallVectorImpl<QualType> &ParamTypes,
2478 QualType *FunctionType,
2479 TemplateDeductionInfo &Info) {
2480 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
2481 TemplateParameterList *TemplateParams
2482 = FunctionTemplate->getTemplateParameters();
2484 if (ExplicitTemplateArgs.size() == 0) {
2485 // No arguments to substitute; just copy over the parameter types and
2486 // fill in the function type.
2487 for (auto P : Function->parameters())
2488 ParamTypes.push_back(P->getType());
2491 *FunctionType = Function->getType();
2495 // Unevaluated SFINAE context.
2496 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
2497 SFINAETrap Trap(*this);
2499 // C++ [temp.arg.explicit]p3:
2500 // Template arguments that are present shall be specified in the
2501 // declaration order of their corresponding template-parameters. The
2502 // template argument list shall not specify more template-arguments than
2503 // there are corresponding template-parameters.
2504 SmallVector<TemplateArgument, 4> Builder;
2506 // Enter a new template instantiation context where we check the
2507 // explicitly-specified template arguments against this function template,
2508 // and then substitute them into the function parameter types.
2509 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
2510 InstantiatingTemplate Inst(*this, Info.getLocation(), FunctionTemplate,
2512 ActiveTemplateInstantiation::ExplicitTemplateArgumentSubstitution,
2514 if (Inst.isInvalid())
2515 return TDK_InstantiationDepth;
2517 if (CheckTemplateArgumentList(FunctionTemplate,
2519 ExplicitTemplateArgs,
2521 Builder) || Trap.hasErrorOccurred()) {
2522 unsigned Index = Builder.size();
2523 if (Index >= TemplateParams->size())
2524 Index = TemplateParams->size() - 1;
2525 Info.Param = makeTemplateParameter(TemplateParams->getParam(Index));
2526 return TDK_InvalidExplicitArguments;
2529 // Form the template argument list from the explicitly-specified
2530 // template arguments.
2531 TemplateArgumentList *ExplicitArgumentList
2532 = TemplateArgumentList::CreateCopy(Context, Builder);
2533 Info.reset(ExplicitArgumentList);
2535 // Template argument deduction and the final substitution should be
2536 // done in the context of the templated declaration. Explicit
2537 // argument substitution, on the other hand, needs to happen in the
2539 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());
2541 // If we deduced template arguments for a template parameter pack,
2542 // note that the template argument pack is partially substituted and record
2543 // the explicit template arguments. They'll be used as part of deduction
2544 // for this template parameter pack.
2545 for (unsigned I = 0, N = Builder.size(); I != N; ++I) {
2546 const TemplateArgument &Arg = Builder[I];
2547 if (Arg.getKind() == TemplateArgument::Pack) {
2548 CurrentInstantiationScope->SetPartiallySubstitutedPack(
2549 TemplateParams->getParam(I),
2556 const FunctionProtoType *Proto
2557 = Function->getType()->getAs<FunctionProtoType>();
2558 assert(Proto && "Function template does not have a prototype?");
2560 // Isolate our substituted parameters from our caller.
2561 LocalInstantiationScope InstScope(*this, /*MergeWithOuterScope*/true);
2563 ExtParameterInfoBuilder ExtParamInfos;
2565 // Instantiate the types of each of the function parameters given the
2566 // explicitly-specified template arguments. If the function has a trailing
2567 // return type, substitute it after the arguments to ensure we substitute
2568 // in lexical order.
2569 if (Proto->hasTrailingReturn()) {
2570 if (SubstParmTypes(Function->getLocation(), Function->parameters(),
2571 Proto->getExtParameterInfosOrNull(),
2572 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
2573 ParamTypes, /*params*/ nullptr, ExtParamInfos))
2574 return TDK_SubstitutionFailure;
2577 // Instantiate the return type.
2578 QualType ResultType;
2580 // C++11 [expr.prim.general]p3:
2581 // If a declaration declares a member function or member function
2582 // template of a class X, the expression this is a prvalue of type
2583 // "pointer to cv-qualifier-seq X" between the optional cv-qualifer-seq
2584 // and the end of the function-definition, member-declarator, or
2586 unsigned ThisTypeQuals = 0;
2587 CXXRecordDecl *ThisContext = nullptr;
2588 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Function)) {
2589 ThisContext = Method->getParent();
2590 ThisTypeQuals = Method->getTypeQualifiers();
2593 CXXThisScopeRAII ThisScope(*this, ThisContext, ThisTypeQuals,
2594 getLangOpts().CPlusPlus11);
2597 SubstType(Proto->getReturnType(),
2598 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
2599 Function->getTypeSpecStartLoc(), Function->getDeclName());
2600 if (ResultType.isNull() || Trap.hasErrorOccurred())
2601 return TDK_SubstitutionFailure;
2604 // Instantiate the types of each of the function parameters given the
2605 // explicitly-specified template arguments if we didn't do so earlier.
2606 if (!Proto->hasTrailingReturn() &&
2607 SubstParmTypes(Function->getLocation(), Function->parameters(),
2608 Proto->getExtParameterInfosOrNull(),
2609 MultiLevelTemplateArgumentList(*ExplicitArgumentList),
2610 ParamTypes, /*params*/ nullptr, ExtParamInfos))
2611 return TDK_SubstitutionFailure;
2614 auto EPI = Proto->getExtProtoInfo();
2615 EPI.ExtParameterInfos = ExtParamInfos.getPointerOrNull(ParamTypes.size());
2616 *FunctionType = BuildFunctionType(ResultType, ParamTypes,
2617 Function->getLocation(),
2618 Function->getDeclName(),
2620 if (FunctionType->isNull() || Trap.hasErrorOccurred())
2621 return TDK_SubstitutionFailure;
2624 // C++ [temp.arg.explicit]p2:
2625 // Trailing template arguments that can be deduced (14.8.2) may be
2626 // omitted from the list of explicit template-arguments. If all of the
2627 // template arguments can be deduced, they may all be omitted; in this
2628 // case, the empty template argument list <> itself may also be omitted.
2630 // Take all of the explicitly-specified arguments and put them into
2631 // the set of deduced template arguments. Explicitly-specified
2632 // parameter packs, however, will be set to NULL since the deduction
2633 // mechanisms handle explicitly-specified argument packs directly.
2634 Deduced.reserve(TemplateParams->size());
2635 for (unsigned I = 0, N = ExplicitArgumentList->size(); I != N; ++I) {
2636 const TemplateArgument &Arg = ExplicitArgumentList->get(I);
2637 if (Arg.getKind() == TemplateArgument::Pack)
2638 Deduced.push_back(DeducedTemplateArgument());
2640 Deduced.push_back(Arg);
2646 /// \brief Check whether the deduced argument type for a call to a function
2647 /// template matches the actual argument type per C++ [temp.deduct.call]p4.
2649 CheckOriginalCallArgDeduction(Sema &S, Sema::OriginalCallArg OriginalArg,
2650 QualType DeducedA) {
2651 ASTContext &Context = S.Context;
2653 QualType A = OriginalArg.OriginalArgType;
2654 QualType OriginalParamType = OriginalArg.OriginalParamType;
2656 // Check for type equality (top-level cv-qualifiers are ignored).
2657 if (Context.hasSameUnqualifiedType(A, DeducedA))
2660 // Strip off references on the argument types; they aren't needed for
2661 // the following checks.
2662 if (const ReferenceType *DeducedARef = DeducedA->getAs<ReferenceType>())
2663 DeducedA = DeducedARef->getPointeeType();
2664 if (const ReferenceType *ARef = A->getAs<ReferenceType>())
2665 A = ARef->getPointeeType();
2667 // C++ [temp.deduct.call]p4:
2668 // [...] However, there are three cases that allow a difference:
2669 // - If the original P is a reference type, the deduced A (i.e., the
2670 // type referred to by the reference) can be more cv-qualified than
2671 // the transformed A.
2672 if (const ReferenceType *OriginalParamRef
2673 = OriginalParamType->getAs<ReferenceType>()) {
2674 // We don't want to keep the reference around any more.
2675 OriginalParamType = OriginalParamRef->getPointeeType();
2677 Qualifiers AQuals = A.getQualifiers();
2678 Qualifiers DeducedAQuals = DeducedA.getQualifiers();
2680 // Under Objective-C++ ARC, the deduced type may have implicitly
2681 // been given strong or (when dealing with a const reference)
2682 // unsafe_unretained lifetime. If so, update the original
2683 // qualifiers to include this lifetime.
2684 if (S.getLangOpts().ObjCAutoRefCount &&
2685 ((DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_Strong &&
2686 AQuals.getObjCLifetime() == Qualifiers::OCL_None) ||
2687 (DeducedAQuals.hasConst() &&
2688 DeducedAQuals.getObjCLifetime() == Qualifiers::OCL_ExplicitNone))) {
2689 AQuals.setObjCLifetime(DeducedAQuals.getObjCLifetime());
2692 if (AQuals == DeducedAQuals) {
2693 // Qualifiers match; there's nothing to do.
2694 } else if (!DeducedAQuals.compatiblyIncludes(AQuals)) {
2697 // Qualifiers are compatible, so have the argument type adopt the
2698 // deduced argument type's qualifiers as if we had performed the
2699 // qualification conversion.
2700 A = Context.getQualifiedType(A.getUnqualifiedType(), DeducedAQuals);
2704 // - The transformed A can be another pointer or pointer to member
2705 // type that can be converted to the deduced A via a qualification
2708 // Also allow conversions which merely strip [[noreturn]] from function types
2709 // (recursively) as an extension.
2710 // FIXME: Currently, this doesn't play nicely with qualification conversions.
2711 bool ObjCLifetimeConversion = false;
2713 if ((A->isAnyPointerType() || A->isMemberPointerType()) &&
2714 (S.IsQualificationConversion(A, DeducedA, false,
2715 ObjCLifetimeConversion) ||
2716 S.IsNoReturnConversion(A, DeducedA, ResultTy)))
2720 // - If P is a class and P has the form simple-template-id, then the
2721 // transformed A can be a derived class of the deduced A. [...]
2722 // [...] Likewise, if P is a pointer to a class of the form
2723 // simple-template-id, the transformed A can be a pointer to a
2724 // derived class pointed to by the deduced A.
2725 if (const PointerType *OriginalParamPtr
2726 = OriginalParamType->getAs<PointerType>()) {
2727 if (const PointerType *DeducedAPtr = DeducedA->getAs<PointerType>()) {
2728 if (const PointerType *APtr = A->getAs<PointerType>()) {
2729 if (A->getPointeeType()->isRecordType()) {
2730 OriginalParamType = OriginalParamPtr->getPointeeType();
2731 DeducedA = DeducedAPtr->getPointeeType();
2732 A = APtr->getPointeeType();
2738 if (Context.hasSameUnqualifiedType(A, DeducedA))
2741 if (A->isRecordType() && isSimpleTemplateIdType(OriginalParamType) &&
2742 S.IsDerivedFrom(SourceLocation(), A, DeducedA))
2748 /// \brief Finish template argument deduction for a function template,
2749 /// checking the deduced template arguments for completeness and forming
2750 /// the function template specialization.
2752 /// \param OriginalCallArgs If non-NULL, the original call arguments against
2753 /// which the deduced argument types should be compared.
2754 Sema::TemplateDeductionResult
2755 Sema::FinishTemplateArgumentDeduction(FunctionTemplateDecl *FunctionTemplate,
2756 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
2757 unsigned NumExplicitlySpecified,
2758 FunctionDecl *&Specialization,
2759 TemplateDeductionInfo &Info,
2760 SmallVectorImpl<OriginalCallArg> const *OriginalCallArgs,
2761 bool PartialOverloading) {
2762 TemplateParameterList *TemplateParams
2763 = FunctionTemplate->getTemplateParameters();
2765 // Unevaluated SFINAE context.
2766 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
2767 SFINAETrap Trap(*this);
2769 // Enter a new template instantiation context while we instantiate the
2770 // actual function declaration.
2771 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(), Deduced.end());
2772 InstantiatingTemplate Inst(*this, Info.getLocation(), FunctionTemplate,
2774 ActiveTemplateInstantiation::DeducedTemplateArgumentSubstitution,
2776 if (Inst.isInvalid())
2777 return TDK_InstantiationDepth;
2779 ContextRAII SavedContext(*this, FunctionTemplate->getTemplatedDecl());
2781 // C++ [temp.deduct.type]p2:
2782 // [...] or if any template argument remains neither deduced nor
2783 // explicitly specified, template argument deduction fails.
2784 SmallVector<TemplateArgument, 4> Builder;
2785 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
2786 NamedDecl *Param = TemplateParams->getParam(I);
2788 if (!Deduced[I].isNull()) {
2789 if (I < NumExplicitlySpecified) {
2790 // We have already fully type-checked and converted this
2791 // argument, because it was explicitly-specified. Just record the
2792 // presence of this argument.
2793 Builder.push_back(Deduced[I]);
2794 // We may have had explicitly-specified template arguments for a
2795 // template parameter pack (that may or may not have been extended
2796 // via additional deduced arguments).
2797 if (Param->isParameterPack() && CurrentInstantiationScope) {
2798 if (CurrentInstantiationScope->getPartiallySubstitutedPack() ==
2800 // Forget the partially-substituted pack; its substitution is now
2802 CurrentInstantiationScope->ResetPartiallySubstitutedPack();
2808 // We have deduced this argument, so it still needs to be
2809 // checked and converted.
2810 if (ConvertDeducedTemplateArgument(*this, Param, Deduced[I],
2811 FunctionTemplate, Info,
2813 Info.Param = makeTemplateParameter(Param);
2814 // FIXME: These template arguments are temporary. Free them!
2815 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder));
2816 return TDK_SubstitutionFailure;
2822 // C++0x [temp.arg.explicit]p3:
2823 // A trailing template parameter pack (14.5.3) not otherwise deduced will
2824 // be deduced to an empty sequence of template arguments.
2825 // FIXME: Where did the word "trailing" come from?
2826 if (Param->isTemplateParameterPack()) {
2827 // We may have had explicitly-specified template arguments for this
2828 // template parameter pack. If so, our empty deduction extends the
2829 // explicitly-specified set (C++0x [temp.arg.explicit]p9).
2830 const TemplateArgument *ExplicitArgs;
2831 unsigned NumExplicitArgs;
2832 if (CurrentInstantiationScope &&
2833 CurrentInstantiationScope->getPartiallySubstitutedPack(&ExplicitArgs,
2836 Builder.push_back(TemplateArgument(
2837 llvm::makeArrayRef(ExplicitArgs, NumExplicitArgs)));
2839 // Forget the partially-substituted pack; its substitution is now
2841 CurrentInstantiationScope->ResetPartiallySubstitutedPack();
2843 // Go through the motions of checking the empty argument pack against
2844 // the parameter pack.
2845 DeducedTemplateArgument DeducedPack(TemplateArgument::getEmptyPack());
2846 if (ConvertDeducedTemplateArgument(*this, Param, DeducedPack,
2847 FunctionTemplate, Info, true,
2849 Info.Param = makeTemplateParameter(Param);
2850 // FIXME: These template arguments are temporary. Free them!
2851 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder));
2852 return TDK_SubstitutionFailure;
2858 // Substitute into the default template argument, if available.
2859 bool HasDefaultArg = false;
2860 TemplateArgumentLoc DefArg
2861 = SubstDefaultTemplateArgumentIfAvailable(FunctionTemplate,
2862 FunctionTemplate->getLocation(),
2863 FunctionTemplate->getSourceRange().getEnd(),
2865 Builder, HasDefaultArg);
2867 // If there was no default argument, deduction is incomplete.
2868 if (DefArg.getArgument().isNull()) {
2869 Info.Param = makeTemplateParameter(
2870 const_cast<NamedDecl *>(TemplateParams->getParam(I)));
2871 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder));
2872 if (PartialOverloading) break;
2874 return HasDefaultArg ? TDK_SubstitutionFailure : TDK_Incomplete;
2877 // Check whether we can actually use the default argument.
2878 if (CheckTemplateArgument(Param, DefArg,
2880 FunctionTemplate->getLocation(),
2881 FunctionTemplate->getSourceRange().getEnd(),
2884 Info.Param = makeTemplateParameter(
2885 const_cast<NamedDecl *>(TemplateParams->getParam(I)));
2886 // FIXME: These template arguments are temporary. Free them!
2887 Info.reset(TemplateArgumentList::CreateCopy(Context, Builder));
2888 return TDK_SubstitutionFailure;
2891 // If we get here, we successfully used the default template argument.
2894 // Form the template argument list from the deduced template arguments.
2895 TemplateArgumentList *DeducedArgumentList
2896 = TemplateArgumentList::CreateCopy(Context, Builder);
2897 Info.reset(DeducedArgumentList);
2899 // Substitute the deduced template arguments into the function template
2900 // declaration to produce the function template specialization.
2901 DeclContext *Owner = FunctionTemplate->getDeclContext();
2902 if (FunctionTemplate->getFriendObjectKind())
2903 Owner = FunctionTemplate->getLexicalDeclContext();
2904 Specialization = cast_or_null<FunctionDecl>(
2905 SubstDecl(FunctionTemplate->getTemplatedDecl(), Owner,
2906 MultiLevelTemplateArgumentList(*DeducedArgumentList)));
2907 if (!Specialization || Specialization->isInvalidDecl())
2908 return TDK_SubstitutionFailure;
2910 assert(Specialization->getPrimaryTemplate()->getCanonicalDecl() ==
2911 FunctionTemplate->getCanonicalDecl());
2913 // If the template argument list is owned by the function template
2914 // specialization, release it.
2915 if (Specialization->getTemplateSpecializationArgs() == DeducedArgumentList &&
2916 !Trap.hasErrorOccurred())
2919 // There may have been an error that did not prevent us from constructing a
2920 // declaration. Mark the declaration invalid and return with a substitution
2922 if (Trap.hasErrorOccurred()) {
2923 Specialization->setInvalidDecl(true);
2924 return TDK_SubstitutionFailure;
2927 if (OriginalCallArgs) {
2928 // C++ [temp.deduct.call]p4:
2929 // In general, the deduction process attempts to find template argument
2930 // values that will make the deduced A identical to A (after the type A
2931 // is transformed as described above). [...]
2932 for (unsigned I = 0, N = OriginalCallArgs->size(); I != N; ++I) {
2933 OriginalCallArg OriginalArg = (*OriginalCallArgs)[I];
2934 unsigned ParamIdx = OriginalArg.ArgIdx;
2936 if (ParamIdx >= Specialization->getNumParams())
2939 QualType DeducedA = Specialization->getParamDecl(ParamIdx)->getType();
2940 if (CheckOriginalCallArgDeduction(*this, OriginalArg, DeducedA)) {
2941 Info.FirstArg = TemplateArgument(DeducedA);
2942 Info.SecondArg = TemplateArgument(OriginalArg.OriginalArgType);
2943 Info.CallArgIndex = OriginalArg.ArgIdx;
2944 return TDK_DeducedMismatch;
2949 // If we suppressed any diagnostics while performing template argument
2950 // deduction, and if we haven't already instantiated this declaration,
2951 // keep track of these diagnostics. They'll be emitted if this specialization
2952 // is actually used.
2953 if (Info.diag_begin() != Info.diag_end()) {
2954 SuppressedDiagnosticsMap::iterator
2955 Pos = SuppressedDiagnostics.find(Specialization->getCanonicalDecl());
2956 if (Pos == SuppressedDiagnostics.end())
2957 SuppressedDiagnostics[Specialization->getCanonicalDecl()]
2958 .append(Info.diag_begin(), Info.diag_end());
2964 /// Gets the type of a function for template-argument-deducton
2965 /// purposes when it's considered as part of an overload set.
2966 static QualType GetTypeOfFunction(Sema &S, const OverloadExpr::FindResult &R,
2968 // We may need to deduce the return type of the function now.
2969 if (S.getLangOpts().CPlusPlus14 && Fn->getReturnType()->isUndeducedType() &&
2970 S.DeduceReturnType(Fn, R.Expression->getExprLoc(), /*Diagnose*/ false))
2973 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Fn))
2974 if (Method->isInstance()) {
2975 // An instance method that's referenced in a form that doesn't
2976 // look like a member pointer is just invalid.
2977 if (!R.HasFormOfMemberPointer) return QualType();
2979 return S.Context.getMemberPointerType(Fn->getType(),
2980 S.Context.getTypeDeclType(Method->getParent()).getTypePtr());
2983 if (!R.IsAddressOfOperand) return Fn->getType();
2984 return S.Context.getPointerType(Fn->getType());
2987 /// Apply the deduction rules for overload sets.
2989 /// \return the null type if this argument should be treated as an
2990 /// undeduced context
2992 ResolveOverloadForDeduction(Sema &S, TemplateParameterList *TemplateParams,
2993 Expr *Arg, QualType ParamType,
2994 bool ParamWasReference) {
2996 OverloadExpr::FindResult R = OverloadExpr::find(Arg);
2998 OverloadExpr *Ovl = R.Expression;
3000 // C++0x [temp.deduct.call]p4
3002 if (ParamWasReference)
3003 TDF |= TDF_ParamWithReferenceType;
3004 if (R.IsAddressOfOperand)
3005 TDF |= TDF_IgnoreQualifiers;
3007 // C++0x [temp.deduct.call]p6:
3008 // When P is a function type, pointer to function type, or pointer
3009 // to member function type:
3011 if (!ParamType->isFunctionType() &&
3012 !ParamType->isFunctionPointerType() &&
3013 !ParamType->isMemberFunctionPointerType()) {
3014 if (Ovl->hasExplicitTemplateArgs()) {
3015 // But we can still look for an explicit specialization.
3016 if (FunctionDecl *ExplicitSpec
3017 = S.ResolveSingleFunctionTemplateSpecialization(Ovl))
3018 return GetTypeOfFunction(S, R, ExplicitSpec);
3022 if (FunctionDecl *Viable =
3023 S.resolveAddressOfOnlyViableOverloadCandidate(Arg, DAP))
3024 return GetTypeOfFunction(S, R, Viable);
3029 // Gather the explicit template arguments, if any.
3030 TemplateArgumentListInfo ExplicitTemplateArgs;
3031 if (Ovl->hasExplicitTemplateArgs())
3032 Ovl->copyTemplateArgumentsInto(ExplicitTemplateArgs);
3034 for (UnresolvedSetIterator I = Ovl->decls_begin(),
3035 E = Ovl->decls_end(); I != E; ++I) {
3036 NamedDecl *D = (*I)->getUnderlyingDecl();
3038 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(D)) {
3039 // - If the argument is an overload set containing one or more
3040 // function templates, the parameter is treated as a
3041 // non-deduced context.
3042 if (!Ovl->hasExplicitTemplateArgs())
3045 // Otherwise, see if we can resolve a function type
3046 FunctionDecl *Specialization = nullptr;
3047 TemplateDeductionInfo Info(Ovl->getNameLoc());
3048 if (S.DeduceTemplateArguments(FunTmpl, &ExplicitTemplateArgs,
3049 Specialization, Info))
3055 FunctionDecl *Fn = cast<FunctionDecl>(D);
3056 QualType ArgType = GetTypeOfFunction(S, R, Fn);
3057 if (ArgType.isNull()) continue;
3059 // Function-to-pointer conversion.
3060 if (!ParamWasReference && ParamType->isPointerType() &&
3061 ArgType->isFunctionType())
3062 ArgType = S.Context.getPointerType(ArgType);
3064 // - If the argument is an overload set (not containing function
3065 // templates), trial argument deduction is attempted using each
3066 // of the members of the set. If deduction succeeds for only one
3067 // of the overload set members, that member is used as the
3068 // argument value for the deduction. If deduction succeeds for
3069 // more than one member of the overload set the parameter is
3070 // treated as a non-deduced context.
3072 // We do all of this in a fresh context per C++0x [temp.deduct.type]p2:
3073 // Type deduction is done independently for each P/A pair, and
3074 // the deduced template argument values are then combined.
3075 // So we do not reject deductions which were made elsewhere.
3076 SmallVector<DeducedTemplateArgument, 8>
3077 Deduced(TemplateParams->size());
3078 TemplateDeductionInfo Info(Ovl->getNameLoc());
3079 Sema::TemplateDeductionResult Result
3080 = DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
3081 ArgType, Info, Deduced, TDF);
3082 if (Result) continue;
3083 if (!Match.isNull()) return QualType();
3090 /// \brief Perform the adjustments to the parameter and argument types
3091 /// described in C++ [temp.deduct.call].
3093 /// \returns true if the caller should not attempt to perform any template
3094 /// argument deduction based on this P/A pair because the argument is an
3095 /// overloaded function set that could not be resolved.
3096 static bool AdjustFunctionParmAndArgTypesForDeduction(Sema &S,
3097 TemplateParameterList *TemplateParams,
3098 QualType &ParamType,
3102 // C++0x [temp.deduct.call]p3:
3103 // If P is a cv-qualified type, the top level cv-qualifiers of P's type
3104 // are ignored for type deduction.
3105 if (ParamType.hasQualifiers())
3106 ParamType = ParamType.getUnqualifiedType();
3108 // [...] If P is a reference type, the type referred to by P is
3109 // used for type deduction.
3110 const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>();
3112 ParamType = ParamRefType->getPointeeType();
3114 // Overload sets usually make this parameter an undeduced context,
3115 // but there are sometimes special circumstances. Typically
3116 // involving a template-id-expr.
3117 if (ArgType == S.Context.OverloadTy) {
3118 ArgType = ResolveOverloadForDeduction(S, TemplateParams,
3120 ParamRefType != nullptr);
3121 if (ArgType.isNull())
3126 // If the argument has incomplete array type, try to complete its type.
3127 if (ArgType->isIncompleteArrayType()) {
3128 S.completeExprArrayBound(Arg);
3129 ArgType = Arg->getType();
3132 // C++0x [temp.deduct.call]p3:
3133 // If P is an rvalue reference to a cv-unqualified template
3134 // parameter and the argument is an lvalue, the type "lvalue
3135 // reference to A" is used in place of A for type deduction.
3136 if (ParamRefType->isRValueReferenceType() &&
3137 !ParamType.getQualifiers() &&
3138 isa<TemplateTypeParmType>(ParamType) &&
3140 ArgType = S.Context.getLValueReferenceType(ArgType);
3142 // C++ [temp.deduct.call]p2:
3143 // If P is not a reference type:
3144 // - If A is an array type, the pointer type produced by the
3145 // array-to-pointer standard conversion (4.2) is used in place of
3146 // A for type deduction; otherwise,
3147 if (ArgType->isArrayType())
3148 ArgType = S.Context.getArrayDecayedType(ArgType);
3149 // - If A is a function type, the pointer type produced by the
3150 // function-to-pointer standard conversion (4.3) is used in place
3151 // of A for type deduction; otherwise,
3152 else if (ArgType->isFunctionType())
3153 ArgType = S.Context.getPointerType(ArgType);
3155 // - If A is a cv-qualified type, the top level cv-qualifiers of A's
3156 // type are ignored for type deduction.
3157 ArgType = ArgType.getUnqualifiedType();
3161 // C++0x [temp.deduct.call]p4:
3162 // In general, the deduction process attempts to find template argument
3163 // values that will make the deduced A identical to A (after the type A
3164 // is transformed as described above). [...]
3165 TDF = TDF_SkipNonDependent;
3167 // - If the original P is a reference type, the deduced A (i.e., the
3168 // type referred to by the reference) can be more cv-qualified than
3169 // the transformed A.
3171 TDF |= TDF_ParamWithReferenceType;
3172 // - The transformed A can be another pointer or pointer to member
3173 // type that can be converted to the deduced A via a qualification
3174 // conversion (4.4).
3175 if (ArgType->isPointerType() || ArgType->isMemberPointerType() ||
3176 ArgType->isObjCObjectPointerType())
3177 TDF |= TDF_IgnoreQualifiers;
3178 // - If P is a class and P has the form simple-template-id, then the
3179 // transformed A can be a derived class of the deduced A. Likewise,
3180 // if P is a pointer to a class of the form simple-template-id, the
3181 // transformed A can be a pointer to a derived class pointed to by
3183 if (isSimpleTemplateIdType(ParamType) ||
3184 (isa<PointerType>(ParamType) &&
3185 isSimpleTemplateIdType(
3186 ParamType->getAs<PointerType>()->getPointeeType())))
3187 TDF |= TDF_DerivedClass;
3193 hasDeducibleTemplateParameters(Sema &S, FunctionTemplateDecl *FunctionTemplate,
3196 static Sema::TemplateDeductionResult DeduceTemplateArgumentByListElement(
3197 Sema &S, TemplateParameterList *TemplateParams, QualType ParamType,
3198 Expr *Arg, TemplateDeductionInfo &Info,
3199 SmallVectorImpl<DeducedTemplateArgument> &Deduced, unsigned TDF);
3201 /// \brief Attempt template argument deduction from an initializer list
3202 /// deemed to be an argument in a function call.
3204 DeduceFromInitializerList(Sema &S, TemplateParameterList *TemplateParams,
3205 QualType AdjustedParamType, InitListExpr *ILE,
3206 TemplateDeductionInfo &Info,
3207 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3208 unsigned TDF, Sema::TemplateDeductionResult &Result) {
3210 // [temp.deduct.call] p1 (post CWG-1591)
3211 // If removing references and cv-qualifiers from P gives
3212 // std::initializer_list<P0> or P0[N] for some P0 and N and the argument is a
3213 // non-empty initializer list (8.5.4), then deduction is performed instead for
3214 // each element of the initializer list, taking P0 as a function template
3215 // parameter type and the initializer element as its argument, and in the
3216 // P0[N] case, if N is a non-type template parameter, N is deduced from the
3217 // length of the initializer list. Otherwise, an initializer list argument
3218 // causes the parameter to be considered a non-deduced context
3220 const bool IsConstSizedArray = AdjustedParamType->isConstantArrayType();
3222 const bool IsDependentSizedArray =
3223 !IsConstSizedArray && AdjustedParamType->isDependentSizedArrayType();
3225 QualType ElTy; // The element type of the std::initializer_list or the array.
3227 const bool IsSTDList = !IsConstSizedArray && !IsDependentSizedArray &&
3228 S.isStdInitializerList(AdjustedParamType, &ElTy);
3230 if (!IsConstSizedArray && !IsDependentSizedArray && !IsSTDList)
3233 Result = Sema::TDK_Success;
3234 // If we are not deducing against the 'T' in a std::initializer_list<T> then
3235 // deduce against the 'T' in T[N].
3236 if (ElTy.isNull()) {
3238 ElTy = S.Context.getAsArrayType(AdjustedParamType)->getElementType();
3240 // Deduction only needs to be done for dependent types.
3241 if (ElTy->isDependentType()) {
3242 for (Expr *E : ILE->inits()) {
3243 if ((Result = DeduceTemplateArgumentByListElement(S, TemplateParams, ElTy,
3244 E, Info, Deduced, TDF)))
3248 if (IsDependentSizedArray) {
3249 const DependentSizedArrayType *ArrTy =
3250 S.Context.getAsDependentSizedArrayType(AdjustedParamType);
3251 // Determine the array bound is something we can deduce.
3252 if (NonTypeTemplateParmDecl *NTTP =
3253 getDeducedParameterFromExpr(ArrTy->getSizeExpr())) {
3254 // We can perform template argument deduction for the given non-type
3255 // template parameter.
3256 assert(NTTP->getDepth() == 0 &&
3257 "Cannot deduce non-type template argument at depth > 0");
3258 llvm::APInt Size(S.Context.getIntWidth(NTTP->getType()),
3259 ILE->getNumInits());
3261 Result = DeduceNonTypeTemplateArgument(
3262 S, NTTP, llvm::APSInt(Size), NTTP->getType(),
3263 /*ArrayBound=*/true, Info, Deduced);
3269 /// \brief Perform template argument deduction by matching a parameter type
3270 /// against a single expression, where the expression is an element of
3271 /// an initializer list that was originally matched against a parameter
3272 /// of type \c initializer_list\<ParamType\>.
3273 static Sema::TemplateDeductionResult
3274 DeduceTemplateArgumentByListElement(Sema &S,
3275 TemplateParameterList *TemplateParams,
3276 QualType ParamType, Expr *Arg,
3277 TemplateDeductionInfo &Info,
3278 SmallVectorImpl<DeducedTemplateArgument> &Deduced,
3280 // Handle the case where an init list contains another init list as the
3282 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) {
3283 Sema::TemplateDeductionResult Result;
3284 if (!DeduceFromInitializerList(S, TemplateParams,
3285 ParamType.getNonReferenceType(), ILE, Info,
3286 Deduced, TDF, Result))
3287 return Sema::TDK_Success; // Just ignore this expression.
3292 // For all other cases, just match by type.
3293 QualType ArgType = Arg->getType();
3294 if (AdjustFunctionParmAndArgTypesForDeduction(S, TemplateParams, ParamType,
3295 ArgType, Arg, TDF)) {
3296 Info.Expression = Arg;
3297 return Sema::TDK_FailedOverloadResolution;
3299 return DeduceTemplateArgumentsByTypeMatch(S, TemplateParams, ParamType,
3300 ArgType, Info, Deduced, TDF);
3303 /// \brief Perform template argument deduction from a function call
3304 /// (C++ [temp.deduct.call]).
3306 /// \param FunctionTemplate the function template for which we are performing
3307 /// template argument deduction.
3309 /// \param ExplicitTemplateArgs the explicit template arguments provided
3312 /// \param Args the function call arguments
3314 /// \param Specialization if template argument deduction was successful,
3315 /// this will be set to the function template specialization produced by
3316 /// template argument deduction.
3318 /// \param Info the argument will be updated to provide additional information
3319 /// about template argument deduction.
3321 /// \returns the result of template argument deduction.
3322 Sema::TemplateDeductionResult Sema::DeduceTemplateArguments(
3323 FunctionTemplateDecl *FunctionTemplate,
3324 TemplateArgumentListInfo *ExplicitTemplateArgs, ArrayRef<Expr *> Args,
3325 FunctionDecl *&Specialization, TemplateDeductionInfo &Info,
3326 bool PartialOverloading) {
3327 if (FunctionTemplate->isInvalidDecl())
3330 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
3331 unsigned NumParams = Function->getNumParams();
3333 // C++ [temp.deduct.call]p1:
3334 // Template argument deduction is done by comparing each function template
3335 // parameter type (call it P) with the type of the corresponding argument
3336 // of the call (call it A) as described below.
3337 unsigned CheckArgs = Args.size();
3338 if (Args.size() < Function->getMinRequiredArguments() && !PartialOverloading)
3339 return TDK_TooFewArguments;
3340 else if (TooManyArguments(NumParams, Args.size(), PartialOverloading)) {
3341 const FunctionProtoType *Proto
3342 = Function->getType()->getAs<FunctionProtoType>();
3343 if (Proto->isTemplateVariadic())
3345 else if (Proto->isVariadic())
3346 CheckArgs = NumParams;
3348 return TDK_TooManyArguments;
3351 // The types of the parameters from which we will perform template argument
3353 LocalInstantiationScope InstScope(*this);
3354 TemplateParameterList *TemplateParams
3355 = FunctionTemplate->getTemplateParameters();
3356 SmallVector<DeducedTemplateArgument, 4> Deduced;
3357 SmallVector<QualType, 4> ParamTypes;
3358 unsigned NumExplicitlySpecified = 0;
3359 if (ExplicitTemplateArgs) {
3360 TemplateDeductionResult Result =
3361 SubstituteExplicitTemplateArguments(FunctionTemplate,
3362 *ExplicitTemplateArgs,
3370 NumExplicitlySpecified = Deduced.size();
3372 // Just fill in the parameter types from the function declaration.
3373 for (unsigned I = 0; I != NumParams; ++I)
3374 ParamTypes.push_back(Function->getParamDecl(I)->getType());
3377 // Deduce template arguments from the function parameters.
3378 Deduced.resize(TemplateParams->size());
3379 unsigned ArgIdx = 0;
3380 SmallVector<OriginalCallArg, 4> OriginalCallArgs;
3381 for (unsigned ParamIdx = 0, NumParamTypes = ParamTypes.size();
3382 ParamIdx != NumParamTypes; ++ParamIdx) {
3383 QualType OrigParamType = ParamTypes[ParamIdx];
3384 QualType ParamType = OrigParamType;
3386 const PackExpansionType *ParamExpansion
3387 = dyn_cast<PackExpansionType>(ParamType);
3388 if (!ParamExpansion) {
3389 // Simple case: matching a function parameter to a function argument.
3390 if (ArgIdx >= CheckArgs)
3393 Expr *Arg = Args[ArgIdx++];
3394 QualType ArgType = Arg->getType();
3397 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams,
3398 ParamType, ArgType, Arg,
3402 // If we have nothing to deduce, we're done.
3403 if (!hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType))
3406 // If the argument is an initializer list ...
3407 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) {
3408 TemplateDeductionResult Result;
3409 // Removing references was already done.
3410 if (!DeduceFromInitializerList(*this, TemplateParams, ParamType, ILE,
3411 Info, Deduced, TDF, Result))
3416 // Don't track the argument type, since an initializer list has none.
3420 // Keep track of the argument type and corresponding parameter index,
3421 // so we can check for compatibility between the deduced A and A.
3422 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx-1,
3425 if (TemplateDeductionResult Result
3426 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
3428 Info, Deduced, TDF))
3434 // C++0x [temp.deduct.call]p1:
3435 // For a function parameter pack that occurs at the end of the
3436 // parameter-declaration-list, the type A of each remaining argument of
3437 // the call is compared with the type P of the declarator-id of the
3438 // function parameter pack. Each comparison deduces template arguments
3439 // for subsequent positions in the template parameter packs expanded by
3440 // the function parameter pack. For a function parameter pack that does
3441 // not occur at the end of the parameter-declaration-list, the type of
3442 // the parameter pack is a non-deduced context.
3443 if (ParamIdx + 1 < NumParamTypes)
3446 QualType ParamPattern = ParamExpansion->getPattern();
3447 PackDeductionScope PackScope(*this, TemplateParams, Deduced, Info,
3450 bool HasAnyArguments = false;
3451 for (; ArgIdx < Args.size(); ++ArgIdx) {
3452 HasAnyArguments = true;
3454 QualType OrigParamType = ParamPattern;
3455 ParamType = OrigParamType;
3456 Expr *Arg = Args[ArgIdx];
3457 QualType ArgType = Arg->getType();
3460 if (AdjustFunctionParmAndArgTypesForDeduction(*this, TemplateParams,
3461 ParamType, ArgType, Arg,
3463 // We can't actually perform any deduction for this argument, so stop
3464 // deduction at this point.
3469 // As above, initializer lists need special handling.
3470 if (InitListExpr *ILE = dyn_cast<InitListExpr>(Arg)) {
3471 TemplateDeductionResult Result;
3472 if (!DeduceFromInitializerList(*this, TemplateParams, ParamType, ILE,
3473 Info, Deduced, TDF, Result)) {
3482 // Keep track of the argument type and corresponding argument index,
3483 // so we can check for compatibility between the deduced A and A.
3484 if (hasDeducibleTemplateParameters(*this, FunctionTemplate, ParamType))
3485 OriginalCallArgs.push_back(OriginalCallArg(OrigParamType, ArgIdx,
3488 if (TemplateDeductionResult Result
3489 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
3490 ParamType, ArgType, Info,
3495 PackScope.nextPackElement();
3498 // Build argument packs for each of the parameter packs expanded by this
3500 if (auto Result = PackScope.finish(HasAnyArguments))
3503 // After we've matching against a parameter pack, we're done.
3507 return FinishTemplateArgumentDeduction(FunctionTemplate, Deduced,
3508 NumExplicitlySpecified, Specialization,
3509 Info, &OriginalCallArgs,
3510 PartialOverloading);
3513 QualType Sema::adjustCCAndNoReturn(QualType ArgFunctionType,
3514 QualType FunctionType) {
3515 if (ArgFunctionType.isNull())
3516 return ArgFunctionType;
3518 const FunctionProtoType *FunctionTypeP =
3519 FunctionType->castAs<FunctionProtoType>();
3520 CallingConv CC = FunctionTypeP->getCallConv();
3521 bool NoReturn = FunctionTypeP->getNoReturnAttr();
3522 const FunctionProtoType *ArgFunctionTypeP =
3523 ArgFunctionType->getAs<FunctionProtoType>();
3524 if (ArgFunctionTypeP->getCallConv() == CC &&
3525 ArgFunctionTypeP->getNoReturnAttr() == NoReturn)
3526 return ArgFunctionType;
3528 FunctionType::ExtInfo EI = ArgFunctionTypeP->getExtInfo().withCallingConv(CC);
3529 EI = EI.withNoReturn(NoReturn);
3531 cast<FunctionProtoType>(Context.adjustFunctionType(ArgFunctionTypeP, EI));
3532 return QualType(ArgFunctionTypeP, 0);
3535 /// \brief Deduce template arguments when taking the address of a function
3536 /// template (C++ [temp.deduct.funcaddr]) or matching a specialization to
3539 /// \param FunctionTemplate the function template for which we are performing
3540 /// template argument deduction.
3542 /// \param ExplicitTemplateArgs the explicitly-specified template
3545 /// \param ArgFunctionType the function type that will be used as the
3546 /// "argument" type (A) when performing template argument deduction from the
3547 /// function template's function type. This type may be NULL, if there is no
3548 /// argument type to compare against, in C++0x [temp.arg.explicit]p3.
3550 /// \param Specialization if template argument deduction was successful,
3551 /// this will be set to the function template specialization produced by
3552 /// template argument deduction.
3554 /// \param Info the argument will be updated to provide additional information
3555 /// about template argument deduction.
3557 /// \returns the result of template argument deduction.
3558 Sema::TemplateDeductionResult
3559 Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
3560 TemplateArgumentListInfo *ExplicitTemplateArgs,
3561 QualType ArgFunctionType,
3562 FunctionDecl *&Specialization,
3563 TemplateDeductionInfo &Info,
3564 bool InOverloadResolution) {
3565 if (FunctionTemplate->isInvalidDecl())
3568 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
3569 TemplateParameterList *TemplateParams
3570 = FunctionTemplate->getTemplateParameters();
3571 QualType FunctionType = Function->getType();
3572 if (!InOverloadResolution)
3573 ArgFunctionType = adjustCCAndNoReturn(ArgFunctionType, FunctionType);
3575 // Substitute any explicit template arguments.
3576 LocalInstantiationScope InstScope(*this);
3577 SmallVector<DeducedTemplateArgument, 4> Deduced;
3578 unsigned NumExplicitlySpecified = 0;
3579 SmallVector<QualType, 4> ParamTypes;
3580 if (ExplicitTemplateArgs) {
3581 if (TemplateDeductionResult Result
3582 = SubstituteExplicitTemplateArguments(FunctionTemplate,
3583 *ExplicitTemplateArgs,
3584 Deduced, ParamTypes,
3585 &FunctionType, Info))
3588 NumExplicitlySpecified = Deduced.size();
3591 // Unevaluated SFINAE context.
3592 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
3593 SFINAETrap Trap(*this);
3595 Deduced.resize(TemplateParams->size());
3597 // If the function has a deduced return type, substitute it for a dependent
3598 // type so that we treat it as a non-deduced context in what follows.
3599 bool HasDeducedReturnType = false;
3600 if (getLangOpts().CPlusPlus14 && InOverloadResolution &&
3601 Function->getReturnType()->getContainedAutoType()) {
3602 FunctionType = SubstAutoType(FunctionType, Context.DependentTy);
3603 HasDeducedReturnType = true;
3606 if (!ArgFunctionType.isNull()) {
3607 unsigned TDF = TDF_TopLevelParameterTypeList;
3608 if (InOverloadResolution) TDF |= TDF_InOverloadResolution;
3609 // Deduce template arguments from the function type.
3610 if (TemplateDeductionResult Result
3611 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
3612 FunctionType, ArgFunctionType,
3613 Info, Deduced, TDF))
3617 if (TemplateDeductionResult Result
3618 = FinishTemplateArgumentDeduction(FunctionTemplate, Deduced,
3619 NumExplicitlySpecified,
3620 Specialization, Info))
3623 // If the function has a deduced return type, deduce it now, so we can check
3624 // that the deduced function type matches the requested type.
3625 if (HasDeducedReturnType &&
3626 Specialization->getReturnType()->isUndeducedType() &&
3627 DeduceReturnType(Specialization, Info.getLocation(), false))
3628 return TDK_MiscellaneousDeductionFailure;
3630 // If the requested function type does not match the actual type of the
3631 // specialization with respect to arguments of compatible pointer to function
3632 // types, template argument deduction fails.
3633 if (!ArgFunctionType.isNull()) {
3634 if (InOverloadResolution && !isSameOrCompatibleFunctionType(
3635 Context.getCanonicalType(Specialization->getType()),
3636 Context.getCanonicalType(ArgFunctionType)))
3637 return TDK_MiscellaneousDeductionFailure;
3638 else if(!InOverloadResolution &&
3639 !Context.hasSameType(Specialization->getType(), ArgFunctionType))
3640 return TDK_MiscellaneousDeductionFailure;
3646 /// \brief Given a function declaration (e.g. a generic lambda conversion
3647 /// function) that contains an 'auto' in its result type, substitute it
3648 /// with TypeToReplaceAutoWith. Be careful to pass in the type you want
3649 /// to replace 'auto' with and not the actual result type you want
3650 /// to set the function to.
3652 SubstAutoWithinFunctionReturnType(FunctionDecl *F,
3653 QualType TypeToReplaceAutoWith, Sema &S) {
3654 assert(!TypeToReplaceAutoWith->getContainedAutoType());
3655 QualType AutoResultType = F->getReturnType();
3656 assert(AutoResultType->getContainedAutoType());
3657 QualType DeducedResultType = S.SubstAutoType(AutoResultType,
3658 TypeToReplaceAutoWith);
3659 S.Context.adjustDeducedFunctionResultType(F, DeducedResultType);
3662 /// \brief Given a specialized conversion operator of a generic lambda
3663 /// create the corresponding specializations of the call operator and
3664 /// the static-invoker. If the return type of the call operator is auto,
3665 /// deduce its return type and check if that matches the
3666 /// return type of the destination function ptr.
3668 static inline Sema::TemplateDeductionResult
3669 SpecializeCorrespondingLambdaCallOperatorAndInvoker(
3670 CXXConversionDecl *ConversionSpecialized,
3671 SmallVectorImpl<DeducedTemplateArgument> &DeducedArguments,
3672 QualType ReturnTypeOfDestFunctionPtr,
3673 TemplateDeductionInfo &TDInfo,
3676 CXXRecordDecl *LambdaClass = ConversionSpecialized->getParent();
3677 assert(LambdaClass && LambdaClass->isGenericLambda());
3679 CXXMethodDecl *CallOpGeneric = LambdaClass->getLambdaCallOperator();
3680 QualType CallOpResultType = CallOpGeneric->getReturnType();
3681 const bool GenericLambdaCallOperatorHasDeducedReturnType =
3682 CallOpResultType->getContainedAutoType();
3684 FunctionTemplateDecl *CallOpTemplate =
3685 CallOpGeneric->getDescribedFunctionTemplate();
3687 FunctionDecl *CallOpSpecialized = nullptr;
3688 // Use the deduced arguments of the conversion function, to specialize our
3689 // generic lambda's call operator.
3690 if (Sema::TemplateDeductionResult Result
3691 = S.FinishTemplateArgumentDeduction(CallOpTemplate,
3693 0, CallOpSpecialized, TDInfo))
3696 // If we need to deduce the return type, do so (instantiates the callop).
3697 if (GenericLambdaCallOperatorHasDeducedReturnType &&
3698 CallOpSpecialized->getReturnType()->isUndeducedType())
3699 S.DeduceReturnType(CallOpSpecialized,
3700 CallOpSpecialized->getPointOfInstantiation(),
3703 // Check to see if the return type of the destination ptr-to-function
3704 // matches the return type of the call operator.
3705 if (!S.Context.hasSameType(CallOpSpecialized->getReturnType(),
3706 ReturnTypeOfDestFunctionPtr))
3707 return Sema::TDK_NonDeducedMismatch;
3708 // Since we have succeeded in matching the source and destination
3709 // ptr-to-functions (now including return type), and have successfully
3710 // specialized our corresponding call operator, we are ready to
3711 // specialize the static invoker with the deduced arguments of our
3713 FunctionDecl *InvokerSpecialized = nullptr;
3714 FunctionTemplateDecl *InvokerTemplate = LambdaClass->
3715 getLambdaStaticInvoker()->getDescribedFunctionTemplate();
3718 Sema::TemplateDeductionResult LLVM_ATTRIBUTE_UNUSED Result =
3720 S.FinishTemplateArgumentDeduction(InvokerTemplate, DeducedArguments, 0,
3721 InvokerSpecialized, TDInfo);
3722 assert(Result == Sema::TDK_Success &&
3723 "If the call operator succeeded so should the invoker!");
3724 // Set the result type to match the corresponding call operator
3725 // specialization's result type.
3726 if (GenericLambdaCallOperatorHasDeducedReturnType &&
3727 InvokerSpecialized->getReturnType()->isUndeducedType()) {
3728 // Be sure to get the type to replace 'auto' with and not
3729 // the full result type of the call op specialization
3730 // to substitute into the 'auto' of the invoker and conversion
3733 // int* (*fp)(int*) = [](auto* a) -> auto* { return a; };
3734 // We don't want to subst 'int*' into 'auto' to get int**.
3736 QualType TypeToReplaceAutoWith = CallOpSpecialized->getReturnType()
3737 ->getContainedAutoType()
3739 SubstAutoWithinFunctionReturnType(InvokerSpecialized,
3740 TypeToReplaceAutoWith, S);
3741 SubstAutoWithinFunctionReturnType(ConversionSpecialized,
3742 TypeToReplaceAutoWith, S);
3745 // Ensure that static invoker doesn't have a const qualifier.
3746 // FIXME: When creating the InvokerTemplate in SemaLambda.cpp
3747 // do not use the CallOperator's TypeSourceInfo which allows
3748 // the const qualifier to leak through.
3749 const FunctionProtoType *InvokerFPT = InvokerSpecialized->
3750 getType().getTypePtr()->castAs<FunctionProtoType>();
3751 FunctionProtoType::ExtProtoInfo EPI = InvokerFPT->getExtProtoInfo();
3753 InvokerSpecialized->setType(S.Context.getFunctionType(
3754 InvokerFPT->getReturnType(), InvokerFPT->getParamTypes(), EPI));
3755 return Sema::TDK_Success;
3757 /// \brief Deduce template arguments for a templated conversion
3758 /// function (C++ [temp.deduct.conv]) and, if successful, produce a
3759 /// conversion function template specialization.
3760 Sema::TemplateDeductionResult
3761 Sema::DeduceTemplateArguments(FunctionTemplateDecl *ConversionTemplate,
3763 CXXConversionDecl *&Specialization,
3764 TemplateDeductionInfo &Info) {
3765 if (ConversionTemplate->isInvalidDecl())
3768 CXXConversionDecl *ConversionGeneric
3769 = cast<CXXConversionDecl>(ConversionTemplate->getTemplatedDecl());
3771 QualType FromType = ConversionGeneric->getConversionType();
3773 // Canonicalize the types for deduction.
3774 QualType P = Context.getCanonicalType(FromType);
3775 QualType A = Context.getCanonicalType(ToType);
3777 // C++0x [temp.deduct.conv]p2:
3778 // If P is a reference type, the type referred to by P is used for
3780 if (const ReferenceType *PRef = P->getAs<ReferenceType>())
3781 P = PRef->getPointeeType();
3783 // C++0x [temp.deduct.conv]p4:
3784 // [...] If A is a reference type, the type referred to by A is used
3785 // for type deduction.
3786 if (const ReferenceType *ARef = A->getAs<ReferenceType>())
3787 A = ARef->getPointeeType().getUnqualifiedType();
3788 // C++ [temp.deduct.conv]p3:
3790 // If A is not a reference type:
3792 assert(!A->isReferenceType() && "Reference types were handled above");
3794 // - If P is an array type, the pointer type produced by the
3795 // array-to-pointer standard conversion (4.2) is used in place
3796 // of P for type deduction; otherwise,
3797 if (P->isArrayType())
3798 P = Context.getArrayDecayedType(P);
3799 // - If P is a function type, the pointer type produced by the
3800 // function-to-pointer standard conversion (4.3) is used in
3801 // place of P for type deduction; otherwise,
3802 else if (P->isFunctionType())
3803 P = Context.getPointerType(P);
3804 // - If P is a cv-qualified type, the top level cv-qualifiers of
3805 // P's type are ignored for type deduction.
3807 P = P.getUnqualifiedType();
3809 // C++0x [temp.deduct.conv]p4:
3810 // If A is a cv-qualified type, the top level cv-qualifiers of A's
3811 // type are ignored for type deduction. If A is a reference type, the type
3812 // referred to by A is used for type deduction.
3813 A = A.getUnqualifiedType();
3816 // Unevaluated SFINAE context.
3817 EnterExpressionEvaluationContext Unevaluated(*this, Sema::Unevaluated);
3818 SFINAETrap Trap(*this);
3820 // C++ [temp.deduct.conv]p1:
3821 // Template argument deduction is done by comparing the return
3822 // type of the template conversion function (call it P) with the
3823 // type that is required as the result of the conversion (call it
3824 // A) as described in 14.8.2.4.
3825 TemplateParameterList *TemplateParams
3826 = ConversionTemplate->getTemplateParameters();
3827 SmallVector<DeducedTemplateArgument, 4> Deduced;
3828 Deduced.resize(TemplateParams->size());
3830 // C++0x [temp.deduct.conv]p4:
3831 // In general, the deduction process attempts to find template
3832 // argument values that will make the deduced A identical to
3833 // A. However, there are two cases that allow a difference:
3835 // - If the original A is a reference type, A can be more
3836 // cv-qualified than the deduced A (i.e., the type referred to
3837 // by the reference)
3838 if (ToType->isReferenceType())
3839 TDF |= TDF_ParamWithReferenceType;
3840 // - The deduced A can be another pointer or pointer to member
3841 // type that can be converted to A via a qualification
3844 // (C++0x [temp.deduct.conv]p6 clarifies that this only happens when
3845 // both P and A are pointers or member pointers. In this case, we
3846 // just ignore cv-qualifiers completely).
3847 if ((P->isPointerType() && A->isPointerType()) ||
3848 (P->isMemberPointerType() && A->isMemberPointerType()))
3849 TDF |= TDF_IgnoreQualifiers;
3850 if (TemplateDeductionResult Result
3851 = DeduceTemplateArgumentsByTypeMatch(*this, TemplateParams,
3852 P, A, Info, Deduced, TDF))
3855 // Create an Instantiation Scope for finalizing the operator.
3856 LocalInstantiationScope InstScope(*this);
3857 // Finish template argument deduction.
3858 FunctionDecl *ConversionSpecialized = nullptr;
3859 TemplateDeductionResult Result
3860 = FinishTemplateArgumentDeduction(ConversionTemplate, Deduced, 0,
3861 ConversionSpecialized, Info);
3862 Specialization = cast_or_null<CXXConversionDecl>(ConversionSpecialized);
3864 // If the conversion operator is being invoked on a lambda closure to convert
3865 // to a ptr-to-function, use the deduced arguments from the conversion
3866 // function to specialize the corresponding call operator.
3867 // e.g., int (*fp)(int) = [](auto a) { return a; };
3868 if (Result == TDK_Success && isLambdaConversionOperator(ConversionGeneric)) {
3870 // Get the return type of the destination ptr-to-function we are converting
3871 // to. This is necessary for matching the lambda call operator's return
3872 // type to that of the destination ptr-to-function's return type.
3873 assert(A->isPointerType() &&
3874 "Can only convert from lambda to ptr-to-function");
3875 const FunctionType *ToFunType =
3876 A->getPointeeType().getTypePtr()->getAs<FunctionType>();
3877 const QualType DestFunctionPtrReturnType = ToFunType->getReturnType();
3879 // Create the corresponding specializations of the call operator and
3880 // the static-invoker; and if the return type is auto,
3881 // deduce the return type and check if it matches the
3882 // DestFunctionPtrReturnType.
3884 // auto L = [](auto a) { return f(a); };
3885 // int (*fp)(int) = L;
3886 // char (*fp2)(int) = L; <-- Not OK.
3888 Result = SpecializeCorrespondingLambdaCallOperatorAndInvoker(
3889 Specialization, Deduced, DestFunctionPtrReturnType,
3895 /// \brief Deduce template arguments for a function template when there is
3896 /// nothing to deduce against (C++0x [temp.arg.explicit]p3).
3898 /// \param FunctionTemplate the function template for which we are performing
3899 /// template argument deduction.
3901 /// \param ExplicitTemplateArgs the explicitly-specified template
3904 /// \param Specialization if template argument deduction was successful,
3905 /// this will be set to the function template specialization produced by
3906 /// template argument deduction.
3908 /// \param Info the argument will be updated to provide additional information
3909 /// about template argument deduction.
3911 /// \returns the result of template argument deduction.
3912 Sema::TemplateDeductionResult
3913 Sema::DeduceTemplateArguments(FunctionTemplateDecl *FunctionTemplate,
3914 TemplateArgumentListInfo *ExplicitTemplateArgs,
3915 FunctionDecl *&Specialization,
3916 TemplateDeductionInfo &Info,
3917 bool InOverloadResolution) {
3918 return DeduceTemplateArguments(FunctionTemplate, ExplicitTemplateArgs,
3919 QualType(), Specialization, Info,
3920 InOverloadResolution);
3924 /// Substitute the 'auto' type specifier within a type for a given replacement
3926 class SubstituteAutoTransform :
3927 public TreeTransform<SubstituteAutoTransform> {
3928 QualType Replacement;
3930 SubstituteAutoTransform(Sema &SemaRef, QualType Replacement)
3931 : TreeTransform<SubstituteAutoTransform>(SemaRef),
3932 Replacement(Replacement) {}
3934 QualType TransformAutoType(TypeLocBuilder &TLB, AutoTypeLoc TL) {
3935 // If we're building the type pattern to deduce against, don't wrap the
3936 // substituted type in an AutoType. Certain template deduction rules
3937 // apply only when a template type parameter appears directly (and not if
3938 // the parameter is found through desugaring). For instance:
3939 // auto &&lref = lvalue;
3940 // must transform into "rvalue reference to T" not "rvalue reference to
3941 // auto type deduced as T" in order for [temp.deduct.call]p3 to apply.
3942 if (!Replacement.isNull() && isa<TemplateTypeParmType>(Replacement)) {
3943 QualType Result = Replacement;
3944 TemplateTypeParmTypeLoc NewTL =
3945 TLB.push<TemplateTypeParmTypeLoc>(Result);
3946 NewTL.setNameLoc(TL.getNameLoc());
3950 !Replacement.isNull() && Replacement->isDependentType();
3952 SemaRef.Context.getAutoType(Dependent ? QualType() : Replacement,
3953 TL.getTypePtr()->getKeyword(),
3955 AutoTypeLoc NewTL = TLB.push<AutoTypeLoc>(Result);
3956 NewTL.setNameLoc(TL.getNameLoc());
3961 ExprResult TransformLambdaExpr(LambdaExpr *E) {
3962 // Lambdas never need to be transformed.
3966 QualType Apply(TypeLoc TL) {
3967 // Create some scratch storage for the transformed type locations.
3968 // FIXME: We're just going to throw this information away. Don't build it.
3970 TLB.reserve(TL.getFullDataSize());
3971 return TransformType(TLB, TL);
3976 Sema::DeduceAutoResult
3977 Sema::DeduceAutoType(TypeSourceInfo *Type, Expr *&Init, QualType &Result) {
3978 return DeduceAutoType(Type->getTypeLoc(), Init, Result);
3981 /// \brief Deduce the type for an auto type-specifier (C++11 [dcl.spec.auto]p6)
3983 /// \param Type the type pattern using the auto type-specifier.
3984 /// \param Init the initializer for the variable whose type is to be deduced.
3985 /// \param Result if type deduction was successful, this will be set to the
3987 Sema::DeduceAutoResult
3988 Sema::DeduceAutoType(TypeLoc Type, Expr *&Init, QualType &Result) {
3989 if (Init->getType()->isNonOverloadPlaceholderType()) {
3990 ExprResult NonPlaceholder = CheckPlaceholderExpr(Init);
3991 if (NonPlaceholder.isInvalid())
3992 return DAR_FailedAlreadyDiagnosed;
3993 Init = NonPlaceholder.get();
3996 if (Init->isTypeDependent() || Type.getType()->isDependentType()) {
3997 Result = SubstituteAutoTransform(*this, Context.DependentTy).Apply(Type);
3998 assert(!Result.isNull() && "substituting DependentTy can't fail");
3999 return DAR_Succeeded;
4002 // If this is a 'decltype(auto)' specifier, do the decltype dance.
4003 // Since 'decltype(auto)' can only occur at the top of the type, we
4004 // don't need to go digging for it.
4005 if (const AutoType *AT = Type.getType()->getAs<AutoType>()) {
4006 if (AT->isDecltypeAuto()) {
4007 if (isa<InitListExpr>(Init)) {
4008 Diag(Init->getLocStart(), diag::err_decltype_auto_initializer_list);
4009 return DAR_FailedAlreadyDiagnosed;
4012 QualType Deduced = BuildDecltypeType(Init, Init->getLocStart(), false);
4013 if (Deduced.isNull())
4014 return DAR_FailedAlreadyDiagnosed;
4015 // FIXME: Support a non-canonical deduced type for 'auto'.
4016 Deduced = Context.getCanonicalType(Deduced);
4017 Result = SubstituteAutoTransform(*this, Deduced).Apply(Type);
4018 if (Result.isNull())
4019 return DAR_FailedAlreadyDiagnosed;
4020 return DAR_Succeeded;
4021 } else if (!getLangOpts().CPlusPlus) {
4022 if (isa<InitListExpr>(Init)) {
4023 Diag(Init->getLocStart(), diag::err_auto_init_list_from_c);
4024 return DAR_FailedAlreadyDiagnosed;
4029 SourceLocation Loc = Init->getExprLoc();
4031 LocalInstantiationScope InstScope(*this);
4033 // Build template<class TemplParam> void Func(FuncParam);
4034 TemplateTypeParmDecl *TemplParam =
4035 TemplateTypeParmDecl::Create(Context, nullptr, SourceLocation(), Loc, 0, 0,
4036 nullptr, false, false);
4037 QualType TemplArg = QualType(TemplParam->getTypeForDecl(), 0);
4038 NamedDecl *TemplParamPtr = TemplParam;
4039 FixedSizeTemplateParameterListStorage<1> TemplateParamsSt(
4040 Loc, Loc, TemplParamPtr, Loc);
4042 QualType FuncParam = SubstituteAutoTransform(*this, TemplArg).Apply(Type);
4043 assert(!FuncParam.isNull() &&
4044 "substituting template parameter for 'auto' failed");
4046 // Deduce type of TemplParam in Func(Init)
4047 SmallVector<DeducedTemplateArgument, 1> Deduced;
4049 QualType InitType = Init->getType();
4052 TemplateDeductionInfo Info(Loc);
4054 InitListExpr *InitList = dyn_cast<InitListExpr>(Init);
4056 for (unsigned i = 0, e = InitList->getNumInits(); i < e; ++i) {
4057 if (DeduceTemplateArgumentByListElement(*this, TemplateParamsSt.get(),
4058 TemplArg, InitList->getInit(i),
4059 Info, Deduced, TDF))
4063 if (!getLangOpts().CPlusPlus && Init->refersToBitField()) {
4064 Diag(Loc, diag::err_auto_bitfield);
4065 return DAR_FailedAlreadyDiagnosed;
4068 if (AdjustFunctionParmAndArgTypesForDeduction(
4069 *this, TemplateParamsSt.get(), FuncParam, InitType, Init, TDF))
4072 if (DeduceTemplateArgumentsByTypeMatch(*this, TemplateParamsSt.get(),
4073 FuncParam, InitType, Info, Deduced,
4078 if (Deduced[0].getKind() != TemplateArgument::Type)
4081 QualType DeducedType = Deduced[0].getAsType();
4084 DeducedType = BuildStdInitializerList(DeducedType, Loc);
4085 if (DeducedType.isNull())
4086 return DAR_FailedAlreadyDiagnosed;
4089 Result = SubstituteAutoTransform(*this, DeducedType).Apply(Type);
4090 if (Result.isNull())
4091 return DAR_FailedAlreadyDiagnosed;
4093 // Check that the deduced argument type is compatible with the original
4094 // argument type per C++ [temp.deduct.call]p4.
4095 if (!InitList && !Result.isNull() &&
4096 CheckOriginalCallArgDeduction(*this,
4097 Sema::OriginalCallArg(FuncParam,0,InitType),
4099 Result = QualType();
4103 return DAR_Succeeded;
4106 QualType Sema::SubstAutoType(QualType TypeWithAuto,
4107 QualType TypeToReplaceAuto) {
4108 return SubstituteAutoTransform(*this, TypeToReplaceAuto).
4109 TransformType(TypeWithAuto);
4112 TypeSourceInfo* Sema::SubstAutoTypeSourceInfo(TypeSourceInfo *TypeWithAuto,
4113 QualType TypeToReplaceAuto) {
4114 return SubstituteAutoTransform(*this, TypeToReplaceAuto).
4115 TransformType(TypeWithAuto);
4118 void Sema::DiagnoseAutoDeductionFailure(VarDecl *VDecl, Expr *Init) {
4119 if (isa<InitListExpr>(Init))
4120 Diag(VDecl->getLocation(),
4121 VDecl->isInitCapture()
4122 ? diag::err_init_capture_deduction_failure_from_init_list
4123 : diag::err_auto_var_deduction_failure_from_init_list)
4124 << VDecl->getDeclName() << VDecl->getType() << Init->getSourceRange();
4126 Diag(VDecl->getLocation(),
4127 VDecl->isInitCapture() ? diag::err_init_capture_deduction_failure
4128 : diag::err_auto_var_deduction_failure)
4129 << VDecl->getDeclName() << VDecl->getType() << Init->getType()
4130 << Init->getSourceRange();
4133 bool Sema::DeduceReturnType(FunctionDecl *FD, SourceLocation Loc,
4135 assert(FD->getReturnType()->isUndeducedType());
4137 if (FD->getTemplateInstantiationPattern())
4138 InstantiateFunctionDefinition(Loc, FD);
4140 bool StillUndeduced = FD->getReturnType()->isUndeducedType();
4141 if (StillUndeduced && Diagnose && !FD->isInvalidDecl()) {
4142 Diag(Loc, diag::err_auto_fn_used_before_defined) << FD;
4143 Diag(FD->getLocation(), diag::note_callee_decl) << FD;
4146 return StillUndeduced;
4150 MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
4153 llvm::SmallBitVector &Deduced);
4155 /// \brief If this is a non-static member function,
4157 AddImplicitObjectParameterType(ASTContext &Context,
4158 CXXMethodDecl *Method,
4159 SmallVectorImpl<QualType> &ArgTypes) {
4160 // C++11 [temp.func.order]p3:
4161 // [...] The new parameter is of type "reference to cv A," where cv are
4162 // the cv-qualifiers of the function template (if any) and A is
4163 // the class of which the function template is a member.
4165 // The standard doesn't say explicitly, but we pick the appropriate kind of
4166 // reference type based on [over.match.funcs]p4.
4167 QualType ArgTy = Context.getTypeDeclType(Method->getParent());
4168 ArgTy = Context.getQualifiedType(ArgTy,
4169 Qualifiers::fromCVRMask(Method->getTypeQualifiers()));
4170 if (Method->getRefQualifier() == RQ_RValue)
4171 ArgTy = Context.getRValueReferenceType(ArgTy);
4173 ArgTy = Context.getLValueReferenceType(ArgTy);
4174 ArgTypes.push_back(ArgTy);
4177 /// \brief Determine whether the function template \p FT1 is at least as
4178 /// specialized as \p FT2.
4179 static bool isAtLeastAsSpecializedAs(Sema &S,
4181 FunctionTemplateDecl *FT1,
4182 FunctionTemplateDecl *FT2,
4183 TemplatePartialOrderingContext TPOC,
4184 unsigned NumCallArguments1) {
4185 FunctionDecl *FD1 = FT1->getTemplatedDecl();
4186 FunctionDecl *FD2 = FT2->getTemplatedDecl();
4187 const FunctionProtoType *Proto1 = FD1->getType()->getAs<FunctionProtoType>();
4188 const FunctionProtoType *Proto2 = FD2->getType()->getAs<FunctionProtoType>();
4190 assert(Proto1 && Proto2 && "Function templates must have prototypes");
4191 TemplateParameterList *TemplateParams = FT2->getTemplateParameters();
4192 SmallVector<DeducedTemplateArgument, 4> Deduced;
4193 Deduced.resize(TemplateParams->size());
4195 // C++0x [temp.deduct.partial]p3:
4196 // The types used to determine the ordering depend on the context in which
4197 // the partial ordering is done:
4198 TemplateDeductionInfo Info(Loc);
4199 SmallVector<QualType, 4> Args2;
4202 // - In the context of a function call, the function parameter types are
4204 CXXMethodDecl *Method1 = dyn_cast<CXXMethodDecl>(FD1);
4205 CXXMethodDecl *Method2 = dyn_cast<CXXMethodDecl>(FD2);
4207 // C++11 [temp.func.order]p3:
4208 // [...] If only one of the function templates is a non-static
4209 // member, that function template is considered to have a new
4210 // first parameter inserted in its function parameter list. The
4211 // new parameter is of type "reference to cv A," where cv are
4212 // the cv-qualifiers of the function template (if any) and A is
4213 // the class of which the function template is a member.
4215 // Note that we interpret this to mean "if one of the function
4216 // templates is a non-static member and the other is a non-member";
4217 // otherwise, the ordering rules for static functions against non-static
4218 // functions don't make any sense.
4220 // C++98/03 doesn't have this provision but we've extended DR532 to cover
4221 // it as wording was broken prior to it.
4222 SmallVector<QualType, 4> Args1;
4224 unsigned NumComparedArguments = NumCallArguments1;
4226 if (!Method2 && Method1 && !Method1->isStatic()) {
4227 // Compare 'this' from Method1 against first parameter from Method2.
4228 AddImplicitObjectParameterType(S.Context, Method1, Args1);
4229 ++NumComparedArguments;
4230 } else if (!Method1 && Method2 && !Method2->isStatic()) {
4231 // Compare 'this' from Method2 against first parameter from Method1.
4232 AddImplicitObjectParameterType(S.Context, Method2, Args2);
4235 Args1.insert(Args1.end(), Proto1->param_type_begin(),
4236 Proto1->param_type_end());
4237 Args2.insert(Args2.end(), Proto2->param_type_begin(),
4238 Proto2->param_type_end());
4240 // C++ [temp.func.order]p5:
4241 // The presence of unused ellipsis and default arguments has no effect on
4242 // the partial ordering of function templates.
4243 if (Args1.size() > NumComparedArguments)
4244 Args1.resize(NumComparedArguments);
4245 if (Args2.size() > NumComparedArguments)
4246 Args2.resize(NumComparedArguments);
4247 if (DeduceTemplateArguments(S, TemplateParams, Args2.data(), Args2.size(),
4248 Args1.data(), Args1.size(), Info, Deduced,
4249 TDF_None, /*PartialOrdering=*/true))
4255 case TPOC_Conversion:
4256 // - In the context of a call to a conversion operator, the return types
4257 // of the conversion function templates are used.
4258 if (DeduceTemplateArgumentsByTypeMatch(
4259 S, TemplateParams, Proto2->getReturnType(), Proto1->getReturnType(),
4260 Info, Deduced, TDF_None,
4261 /*PartialOrdering=*/true))
4266 // - In other contexts (14.6.6.2) the function template's function type
4268 if (DeduceTemplateArgumentsByTypeMatch(S, TemplateParams,
4269 FD2->getType(), FD1->getType(),
4270 Info, Deduced, TDF_None,
4271 /*PartialOrdering=*/true))
4276 // C++0x [temp.deduct.partial]p11:
4277 // In most cases, all template parameters must have values in order for
4278 // deduction to succeed, but for partial ordering purposes a template
4279 // parameter may remain without a value provided it is not used in the
4280 // types being used for partial ordering. [ Note: a template parameter used
4281 // in a non-deduced context is considered used. -end note]
4282 unsigned ArgIdx = 0, NumArgs = Deduced.size();
4283 for (; ArgIdx != NumArgs; ++ArgIdx)
4284 if (Deduced[ArgIdx].isNull())
4287 if (ArgIdx == NumArgs) {
4288 // All template arguments were deduced. FT1 is at least as specialized
4293 // Figure out which template parameters were used.
4294 llvm::SmallBitVector UsedParameters(TemplateParams->size());
4297 for (unsigned I = 0, N = Args2.size(); I != N; ++I)
4298 ::MarkUsedTemplateParameters(S.Context, Args2[I], false,
4299 TemplateParams->getDepth(),
4303 case TPOC_Conversion:
4304 ::MarkUsedTemplateParameters(S.Context, Proto2->getReturnType(), false,
4305 TemplateParams->getDepth(), UsedParameters);
4309 ::MarkUsedTemplateParameters(S.Context, FD2->getType(), false,
4310 TemplateParams->getDepth(),
4315 for (; ArgIdx != NumArgs; ++ArgIdx)
4316 // If this argument had no value deduced but was used in one of the types
4317 // used for partial ordering, then deduction fails.
4318 if (Deduced[ArgIdx].isNull() && UsedParameters[ArgIdx])
4324 /// \brief Determine whether this a function template whose parameter-type-list
4325 /// ends with a function parameter pack.
4326 static bool isVariadicFunctionTemplate(FunctionTemplateDecl *FunTmpl) {
4327 FunctionDecl *Function = FunTmpl->getTemplatedDecl();
4328 unsigned NumParams = Function->getNumParams();
4332 ParmVarDecl *Last = Function->getParamDecl(NumParams - 1);
4333 if (!Last->isParameterPack())
4336 // Make sure that no previous parameter is a parameter pack.
4337 while (--NumParams > 0) {
4338 if (Function->getParamDecl(NumParams - 1)->isParameterPack())
4345 /// \brief Returns the more specialized function template according
4346 /// to the rules of function template partial ordering (C++ [temp.func.order]).
4348 /// \param FT1 the first function template
4350 /// \param FT2 the second function template
4352 /// \param TPOC the context in which we are performing partial ordering of
4353 /// function templates.
4355 /// \param NumCallArguments1 The number of arguments in the call to FT1, used
4356 /// only when \c TPOC is \c TPOC_Call.
4358 /// \param NumCallArguments2 The number of arguments in the call to FT2, used
4359 /// only when \c TPOC is \c TPOC_Call.
4361 /// \returns the more specialized function template. If neither
4362 /// template is more specialized, returns NULL.
4363 FunctionTemplateDecl *
4364 Sema::getMoreSpecializedTemplate(FunctionTemplateDecl *FT1,
4365 FunctionTemplateDecl *FT2,
4367 TemplatePartialOrderingContext TPOC,
4368 unsigned NumCallArguments1,
4369 unsigned NumCallArguments2) {
4370 bool Better1 = isAtLeastAsSpecializedAs(*this, Loc, FT1, FT2, TPOC,
4372 bool Better2 = isAtLeastAsSpecializedAs(*this, Loc, FT2, FT1, TPOC,
4375 if (Better1 != Better2) // We have a clear winner
4376 return Better1 ? FT1 : FT2;
4378 if (!Better1 && !Better2) // Neither is better than the other
4381 // FIXME: This mimics what GCC implements, but doesn't match up with the
4382 // proposed resolution for core issue 692. This area needs to be sorted out,
4383 // but for now we attempt to maintain compatibility.
4384 bool Variadic1 = isVariadicFunctionTemplate(FT1);
4385 bool Variadic2 = isVariadicFunctionTemplate(FT2);
4386 if (Variadic1 != Variadic2)
4387 return Variadic1? FT2 : FT1;
4392 /// \brief Determine if the two templates are equivalent.
4393 static bool isSameTemplate(TemplateDecl *T1, TemplateDecl *T2) {
4400 return T1->getCanonicalDecl() == T2->getCanonicalDecl();
4403 /// \brief Retrieve the most specialized of the given function template
4404 /// specializations.
4406 /// \param SpecBegin the start iterator of the function template
4407 /// specializations that we will be comparing.
4409 /// \param SpecEnd the end iterator of the function template
4410 /// specializations, paired with \p SpecBegin.
4412 /// \param Loc the location where the ambiguity or no-specializations
4413 /// diagnostic should occur.
4415 /// \param NoneDiag partial diagnostic used to diagnose cases where there are
4416 /// no matching candidates.
4418 /// \param AmbigDiag partial diagnostic used to diagnose an ambiguity, if one
4421 /// \param CandidateDiag partial diagnostic used for each function template
4422 /// specialization that is a candidate in the ambiguous ordering. One parameter
4423 /// in this diagnostic should be unbound, which will correspond to the string
4424 /// describing the template arguments for the function template specialization.
4426 /// \returns the most specialized function template specialization, if
4427 /// found. Otherwise, returns SpecEnd.
4428 UnresolvedSetIterator Sema::getMostSpecialized(
4429 UnresolvedSetIterator SpecBegin, UnresolvedSetIterator SpecEnd,
4430 TemplateSpecCandidateSet &FailedCandidates,
4431 SourceLocation Loc, const PartialDiagnostic &NoneDiag,
4432 const PartialDiagnostic &AmbigDiag, const PartialDiagnostic &CandidateDiag,
4433 bool Complain, QualType TargetType) {
4434 if (SpecBegin == SpecEnd) {
4436 Diag(Loc, NoneDiag);
4437 FailedCandidates.NoteCandidates(*this, Loc);
4442 if (SpecBegin + 1 == SpecEnd)
4445 // Find the function template that is better than all of the templates it
4446 // has been compared to.
4447 UnresolvedSetIterator Best = SpecBegin;
4448 FunctionTemplateDecl *BestTemplate
4449 = cast<FunctionDecl>(*Best)->getPrimaryTemplate();
4450 assert(BestTemplate && "Not a function template specialization?");
4451 for (UnresolvedSetIterator I = SpecBegin + 1; I != SpecEnd; ++I) {
4452 FunctionTemplateDecl *Challenger
4453 = cast<FunctionDecl>(*I)->getPrimaryTemplate();
4454 assert(Challenger && "Not a function template specialization?");
4455 if (isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
4456 Loc, TPOC_Other, 0, 0),
4459 BestTemplate = Challenger;
4463 // Make sure that the "best" function template is more specialized than all
4465 bool Ambiguous = false;
4466 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
4467 FunctionTemplateDecl *Challenger
4468 = cast<FunctionDecl>(*I)->getPrimaryTemplate();
4470 !isSameTemplate(getMoreSpecializedTemplate(BestTemplate, Challenger,
4471 Loc, TPOC_Other, 0, 0),
4479 // We found an answer. Return it.
4483 // Diagnose the ambiguity.
4485 Diag(Loc, AmbigDiag);
4487 // FIXME: Can we order the candidates in some sane way?
4488 for (UnresolvedSetIterator I = SpecBegin; I != SpecEnd; ++I) {
4489 PartialDiagnostic PD = CandidateDiag;
4490 PD << getTemplateArgumentBindingsText(
4491 cast<FunctionDecl>(*I)->getPrimaryTemplate()->getTemplateParameters(),
4492 *cast<FunctionDecl>(*I)->getTemplateSpecializationArgs());
4493 if (!TargetType.isNull())
4494 HandleFunctionTypeMismatch(PD, cast<FunctionDecl>(*I)->getType(),
4496 Diag((*I)->getLocation(), PD);
4503 /// \brief Returns the more specialized class template partial specialization
4504 /// according to the rules of partial ordering of class template partial
4505 /// specializations (C++ [temp.class.order]).
4507 /// \param PS1 the first class template partial specialization
4509 /// \param PS2 the second class template partial specialization
4511 /// \returns the more specialized class template partial specialization. If
4512 /// neither partial specialization is more specialized, returns NULL.
4513 ClassTemplatePartialSpecializationDecl *
4514 Sema::getMoreSpecializedPartialSpecialization(
4515 ClassTemplatePartialSpecializationDecl *PS1,
4516 ClassTemplatePartialSpecializationDecl *PS2,
4517 SourceLocation Loc) {
4518 // C++ [temp.class.order]p1:
4519 // For two class template partial specializations, the first is at least as
4520 // specialized as the second if, given the following rewrite to two
4521 // function templates, the first function template is at least as
4522 // specialized as the second according to the ordering rules for function
4523 // templates (14.6.6.2):
4524 // - the first function template has the same template parameters as the
4525 // first partial specialization and has a single function parameter
4526 // whose type is a class template specialization with the template
4527 // arguments of the first partial specialization, and
4528 // - the second function template has the same template parameters as the
4529 // second partial specialization and has a single function parameter
4530 // whose type is a class template specialization with the template
4531 // arguments of the second partial specialization.
4533 // Rather than synthesize function templates, we merely perform the
4534 // equivalent partial ordering by performing deduction directly on
4535 // the template arguments of the class template partial
4536 // specializations. This computation is slightly simpler than the
4537 // general problem of function template partial ordering, because
4538 // class template partial specializations are more constrained. We
4539 // know that every template parameter is deducible from the class
4540 // template partial specialization's template arguments, for
4542 SmallVector<DeducedTemplateArgument, 4> Deduced;
4543 TemplateDeductionInfo Info(Loc);
4545 QualType PT1 = PS1->getInjectedSpecializationType();
4546 QualType PT2 = PS2->getInjectedSpecializationType();
4548 // Determine whether PS1 is at least as specialized as PS2
4549 Deduced.resize(PS2->getTemplateParameters()->size());
4550 bool Better1 = !DeduceTemplateArgumentsByTypeMatch(*this,
4551 PS2->getTemplateParameters(),
4552 PT2, PT1, Info, Deduced, TDF_None,
4553 /*PartialOrdering=*/true);
4555 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),Deduced.end());
4556 InstantiatingTemplate Inst(*this, Loc, PS2, DeducedArgs, Info);
4557 Better1 = !::FinishTemplateArgumentDeduction(
4558 *this, PS2, PS1->getTemplateArgs(), Deduced, Info);
4561 // Determine whether PS2 is at least as specialized as PS1
4563 Deduced.resize(PS1->getTemplateParameters()->size());
4564 bool Better2 = !DeduceTemplateArgumentsByTypeMatch(
4565 *this, PS1->getTemplateParameters(), PT1, PT2, Info, Deduced, TDF_None,
4566 /*PartialOrdering=*/true);
4568 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),
4570 InstantiatingTemplate Inst(*this, Loc, PS1, DeducedArgs, Info);
4571 Better2 = !::FinishTemplateArgumentDeduction(
4572 *this, PS1, PS2->getTemplateArgs(), Deduced, Info);
4575 if (Better1 == Better2)
4578 return Better1 ? PS1 : PS2;
4581 /// TODO: Unify with ClassTemplatePartialSpecializationDecl version?
4582 /// May require unifying ClassTemplate(Partial)SpecializationDecl and
4583 /// VarTemplate(Partial)SpecializationDecl with a new data
4584 /// structure Template(Partial)SpecializationDecl, and
4585 /// using Template(Partial)SpecializationDecl as input type.
4586 VarTemplatePartialSpecializationDecl *
4587 Sema::getMoreSpecializedPartialSpecialization(
4588 VarTemplatePartialSpecializationDecl *PS1,
4589 VarTemplatePartialSpecializationDecl *PS2, SourceLocation Loc) {
4590 SmallVector<DeducedTemplateArgument, 4> Deduced;
4591 TemplateDeductionInfo Info(Loc);
4593 assert(PS1->getSpecializedTemplate() == PS2->getSpecializedTemplate() &&
4594 "the partial specializations being compared should specialize"
4595 " the same template.");
4596 TemplateName Name(PS1->getSpecializedTemplate());
4597 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
4598 QualType PT1 = Context.getTemplateSpecializationType(
4599 CanonTemplate, PS1->getTemplateArgs().asArray());
4600 QualType PT2 = Context.getTemplateSpecializationType(
4601 CanonTemplate, PS2->getTemplateArgs().asArray());
4603 // Determine whether PS1 is at least as specialized as PS2
4604 Deduced.resize(PS2->getTemplateParameters()->size());
4605 bool Better1 = !DeduceTemplateArgumentsByTypeMatch(
4606 *this, PS2->getTemplateParameters(), PT2, PT1, Info, Deduced, TDF_None,
4607 /*PartialOrdering=*/true);
4609 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),
4611 InstantiatingTemplate Inst(*this, Loc, PS2, DeducedArgs, Info);
4612 Better1 = !::FinishTemplateArgumentDeduction(*this, PS2,
4613 PS1->getTemplateArgs(),
4617 // Determine whether PS2 is at least as specialized as PS1
4619 Deduced.resize(PS1->getTemplateParameters()->size());
4620 bool Better2 = !DeduceTemplateArgumentsByTypeMatch(*this,
4621 PS1->getTemplateParameters(),
4622 PT1, PT2, Info, Deduced, TDF_None,
4623 /*PartialOrdering=*/true);
4625 SmallVector<TemplateArgument, 4> DeducedArgs(Deduced.begin(),Deduced.end());
4626 InstantiatingTemplate Inst(*this, Loc, PS1, DeducedArgs, Info);
4627 Better2 = !::FinishTemplateArgumentDeduction(*this, PS1,
4628 PS2->getTemplateArgs(),
4632 if (Better1 == Better2)
4635 return Better1? PS1 : PS2;
4639 MarkUsedTemplateParameters(ASTContext &Ctx,
4640 const TemplateArgument &TemplateArg,
4643 llvm::SmallBitVector &Used);
4645 /// \brief Mark the template parameters that are used by the given
4648 MarkUsedTemplateParameters(ASTContext &Ctx,
4652 llvm::SmallBitVector &Used) {
4653 // We can deduce from a pack expansion.
4654 if (const PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(E))
4655 E = Expansion->getPattern();
4657 // Skip through any implicit casts we added while type-checking, and any
4658 // substitutions performed by template alias expansion.
4660 if (const ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(E))
4661 E = ICE->getSubExpr();
4662 else if (const SubstNonTypeTemplateParmExpr *Subst =
4663 dyn_cast<SubstNonTypeTemplateParmExpr>(E))
4664 E = Subst->getReplacement();
4669 // FIXME: if !OnlyDeduced, we have to walk the whole subexpression to
4670 // find other occurrences of template parameters.
4671 const DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(E);
4675 const NonTypeTemplateParmDecl *NTTP
4676 = dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
4680 if (NTTP->getDepth() == Depth)
4681 Used[NTTP->getIndex()] = true;
4684 /// \brief Mark the template parameters that are used by the given
4685 /// nested name specifier.
4687 MarkUsedTemplateParameters(ASTContext &Ctx,
4688 NestedNameSpecifier *NNS,
4691 llvm::SmallBitVector &Used) {
4695 MarkUsedTemplateParameters(Ctx, NNS->getPrefix(), OnlyDeduced, Depth,
4697 MarkUsedTemplateParameters(Ctx, QualType(NNS->getAsType(), 0),
4698 OnlyDeduced, Depth, Used);
4701 /// \brief Mark the template parameters that are used by the given
4704 MarkUsedTemplateParameters(ASTContext &Ctx,
4708 llvm::SmallBitVector &Used) {
4709 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
4710 if (TemplateTemplateParmDecl *TTP
4711 = dyn_cast<TemplateTemplateParmDecl>(Template)) {
4712 if (TTP->getDepth() == Depth)
4713 Used[TTP->getIndex()] = true;
4718 if (QualifiedTemplateName *QTN = Name.getAsQualifiedTemplateName())
4719 MarkUsedTemplateParameters(Ctx, QTN->getQualifier(), OnlyDeduced,
4721 if (DependentTemplateName *DTN = Name.getAsDependentTemplateName())
4722 MarkUsedTemplateParameters(Ctx, DTN->getQualifier(), OnlyDeduced,
4726 /// \brief Mark the template parameters that are used by the given
4729 MarkUsedTemplateParameters(ASTContext &Ctx, QualType T,
4732 llvm::SmallBitVector &Used) {
4736 // Non-dependent types have nothing deducible
4737 if (!T->isDependentType())
4740 T = Ctx.getCanonicalType(T);
4741 switch (T->getTypeClass()) {
4743 MarkUsedTemplateParameters(Ctx,
4744 cast<PointerType>(T)->getPointeeType(),
4750 case Type::BlockPointer:
4751 MarkUsedTemplateParameters(Ctx,
4752 cast<BlockPointerType>(T)->getPointeeType(),
4758 case Type::LValueReference:
4759 case Type::RValueReference:
4760 MarkUsedTemplateParameters(Ctx,
4761 cast<ReferenceType>(T)->getPointeeType(),
4767 case Type::MemberPointer: {
4768 const MemberPointerType *MemPtr = cast<MemberPointerType>(T.getTypePtr());
4769 MarkUsedTemplateParameters(Ctx, MemPtr->getPointeeType(), OnlyDeduced,
4771 MarkUsedTemplateParameters(Ctx, QualType(MemPtr->getClass(), 0),
4772 OnlyDeduced, Depth, Used);
4776 case Type::DependentSizedArray:
4777 MarkUsedTemplateParameters(Ctx,
4778 cast<DependentSizedArrayType>(T)->getSizeExpr(),
4779 OnlyDeduced, Depth, Used);
4780 // Fall through to check the element type
4782 case Type::ConstantArray:
4783 case Type::IncompleteArray:
4784 MarkUsedTemplateParameters(Ctx,
4785 cast<ArrayType>(T)->getElementType(),
4786 OnlyDeduced, Depth, Used);
4790 case Type::ExtVector:
4791 MarkUsedTemplateParameters(Ctx,
4792 cast<VectorType>(T)->getElementType(),
4793 OnlyDeduced, Depth, Used);
4796 case Type::DependentSizedExtVector: {
4797 const DependentSizedExtVectorType *VecType
4798 = cast<DependentSizedExtVectorType>(T);
4799 MarkUsedTemplateParameters(Ctx, VecType->getElementType(), OnlyDeduced,
4801 MarkUsedTemplateParameters(Ctx, VecType->getSizeExpr(), OnlyDeduced,
4806 case Type::FunctionProto: {
4807 const FunctionProtoType *Proto = cast<FunctionProtoType>(T);
4808 MarkUsedTemplateParameters(Ctx, Proto->getReturnType(), OnlyDeduced, Depth,
4810 for (unsigned I = 0, N = Proto->getNumParams(); I != N; ++I)
4811 MarkUsedTemplateParameters(Ctx, Proto->getParamType(I), OnlyDeduced,
4816 case Type::TemplateTypeParm: {
4817 const TemplateTypeParmType *TTP = cast<TemplateTypeParmType>(T);
4818 if (TTP->getDepth() == Depth)
4819 Used[TTP->getIndex()] = true;
4823 case Type::SubstTemplateTypeParmPack: {
4824 const SubstTemplateTypeParmPackType *Subst
4825 = cast<SubstTemplateTypeParmPackType>(T);
4826 MarkUsedTemplateParameters(Ctx,
4827 QualType(Subst->getReplacedParameter(), 0),
4828 OnlyDeduced, Depth, Used);
4829 MarkUsedTemplateParameters(Ctx, Subst->getArgumentPack(),
4830 OnlyDeduced, Depth, Used);
4834 case Type::InjectedClassName:
4835 T = cast<InjectedClassNameType>(T)->getInjectedSpecializationType();
4838 case Type::TemplateSpecialization: {
4839 const TemplateSpecializationType *Spec
4840 = cast<TemplateSpecializationType>(T);
4841 MarkUsedTemplateParameters(Ctx, Spec->getTemplateName(), OnlyDeduced,
4844 // C++0x [temp.deduct.type]p9:
4845 // If the template argument list of P contains a pack expansion that is
4846 // not the last template argument, the entire template argument list is a
4847 // non-deduced context.
4849 hasPackExpansionBeforeEnd(Spec->getArgs(), Spec->getNumArgs()))
4852 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
4853 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
4860 MarkUsedTemplateParameters(Ctx,
4861 cast<ComplexType>(T)->getElementType(),
4862 OnlyDeduced, Depth, Used);
4867 MarkUsedTemplateParameters(Ctx,
4868 cast<AtomicType>(T)->getValueType(),
4869 OnlyDeduced, Depth, Used);
4872 case Type::DependentName:
4874 MarkUsedTemplateParameters(Ctx,
4875 cast<DependentNameType>(T)->getQualifier(),
4876 OnlyDeduced, Depth, Used);
4879 case Type::DependentTemplateSpecialization: {
4880 // C++14 [temp.deduct.type]p5:
4881 // The non-deduced contexts are:
4882 // -- The nested-name-specifier of a type that was specified using a
4885 // C++14 [temp.deduct.type]p6:
4886 // When a type name is specified in a way that includes a non-deduced
4887 // context, all of the types that comprise that type name are also
4892 const DependentTemplateSpecializationType *Spec
4893 = cast<DependentTemplateSpecializationType>(T);
4895 MarkUsedTemplateParameters(Ctx, Spec->getQualifier(),
4896 OnlyDeduced, Depth, Used);
4898 for (unsigned I = 0, N = Spec->getNumArgs(); I != N; ++I)
4899 MarkUsedTemplateParameters(Ctx, Spec->getArg(I), OnlyDeduced, Depth,
4906 MarkUsedTemplateParameters(Ctx,
4907 cast<TypeOfType>(T)->getUnderlyingType(),
4908 OnlyDeduced, Depth, Used);
4911 case Type::TypeOfExpr:
4913 MarkUsedTemplateParameters(Ctx,
4914 cast<TypeOfExprType>(T)->getUnderlyingExpr(),
4915 OnlyDeduced, Depth, Used);
4918 case Type::Decltype:
4920 MarkUsedTemplateParameters(Ctx,
4921 cast<DecltypeType>(T)->getUnderlyingExpr(),
4922 OnlyDeduced, Depth, Used);
4925 case Type::UnaryTransform:
4927 MarkUsedTemplateParameters(Ctx,
4928 cast<UnaryTransformType>(T)->getUnderlyingType(),
4929 OnlyDeduced, Depth, Used);
4932 case Type::PackExpansion:
4933 MarkUsedTemplateParameters(Ctx,
4934 cast<PackExpansionType>(T)->getPattern(),
4935 OnlyDeduced, Depth, Used);
4939 MarkUsedTemplateParameters(Ctx,
4940 cast<AutoType>(T)->getDeducedType(),
4941 OnlyDeduced, Depth, Used);
4943 // None of these types have any template parameters in them.
4945 case Type::VariableArray:
4946 case Type::FunctionNoProto:
4949 case Type::ObjCInterface:
4950 case Type::ObjCObject:
4951 case Type::ObjCObjectPointer:
4952 case Type::UnresolvedUsing:
4954 #define TYPE(Class, Base)
4955 #define ABSTRACT_TYPE(Class, Base)
4956 #define DEPENDENT_TYPE(Class, Base)
4957 #define NON_CANONICAL_TYPE(Class, Base) case Type::Class:
4958 #include "clang/AST/TypeNodes.def"
4963 /// \brief Mark the template parameters that are used by this
4964 /// template argument.
4966 MarkUsedTemplateParameters(ASTContext &Ctx,
4967 const TemplateArgument &TemplateArg,
4970 llvm::SmallBitVector &Used) {
4971 switch (TemplateArg.getKind()) {
4972 case TemplateArgument::Null:
4973 case TemplateArgument::Integral:
4974 case TemplateArgument::Declaration:
4977 case TemplateArgument::NullPtr:
4978 MarkUsedTemplateParameters(Ctx, TemplateArg.getNullPtrType(), OnlyDeduced,
4982 case TemplateArgument::Type:
4983 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsType(), OnlyDeduced,
4987 case TemplateArgument::Template:
4988 case TemplateArgument::TemplateExpansion:
4989 MarkUsedTemplateParameters(Ctx,
4990 TemplateArg.getAsTemplateOrTemplatePattern(),
4991 OnlyDeduced, Depth, Used);
4994 case TemplateArgument::Expression:
4995 MarkUsedTemplateParameters(Ctx, TemplateArg.getAsExpr(), OnlyDeduced,
4999 case TemplateArgument::Pack:
5000 for (const auto &P : TemplateArg.pack_elements())
5001 MarkUsedTemplateParameters(Ctx, P, OnlyDeduced, Depth, Used);
5006 /// \brief Mark which template parameters can be deduced from a given
5007 /// template argument list.
5009 /// \param TemplateArgs the template argument list from which template
5010 /// parameters will be deduced.
5012 /// \param Used a bit vector whose elements will be set to \c true
5013 /// to indicate when the corresponding template parameter will be
5016 Sema::MarkUsedTemplateParameters(const TemplateArgumentList &TemplateArgs,
5017 bool OnlyDeduced, unsigned Depth,
5018 llvm::SmallBitVector &Used) {
5019 // C++0x [temp.deduct.type]p9:
5020 // If the template argument list of P contains a pack expansion that is not
5021 // the last template argument, the entire template argument list is a
5022 // non-deduced context.
5024 hasPackExpansionBeforeEnd(TemplateArgs.data(), TemplateArgs.size()))
5027 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
5028 ::MarkUsedTemplateParameters(Context, TemplateArgs[I], OnlyDeduced,
5032 /// \brief Marks all of the template parameters that will be deduced by a
5033 /// call to the given function template.
5034 void Sema::MarkDeducedTemplateParameters(
5035 ASTContext &Ctx, const FunctionTemplateDecl *FunctionTemplate,
5036 llvm::SmallBitVector &Deduced) {
5037 TemplateParameterList *TemplateParams
5038 = FunctionTemplate->getTemplateParameters();
5040 Deduced.resize(TemplateParams->size());
5042 FunctionDecl *Function = FunctionTemplate->getTemplatedDecl();
5043 for (unsigned I = 0, N = Function->getNumParams(); I != N; ++I)
5044 ::MarkUsedTemplateParameters(Ctx, Function->getParamDecl(I)->getType(),
5045 true, TemplateParams->getDepth(), Deduced);
5048 bool hasDeducibleTemplateParameters(Sema &S,
5049 FunctionTemplateDecl *FunctionTemplate,
5051 if (!T->isDependentType())
5054 TemplateParameterList *TemplateParams
5055 = FunctionTemplate->getTemplateParameters();
5056 llvm::SmallBitVector Deduced(TemplateParams->size());
5057 ::MarkUsedTemplateParameters(S.Context, T, true, TemplateParams->getDepth(),
5060 return Deduced.any();