Index: clang/docs/ReleaseNotes.rst =================================================================== --- clang/docs/ReleaseNotes.rst +++ clang/docs/ReleaseNotes.rst @@ -195,6 +195,10 @@ `Issue 54578 `_. - Implemented `__builtin_source_location()` which enables library support for std::source_location. +- Clang now correctly delays the instantiation of function constraints until + the time of checking, which should now allow the libstdc++ ranges implementation + to work for at least trivial examples. This fixes + `Issue 44178 `_. C++2b Feature Support ^^^^^^^^^^^^^^^^^^^^^ Index: clang/include/clang/Sema/Sema.h =================================================================== --- clang/include/clang/Sema/Sema.h +++ clang/include/clang/Sema/Sema.h @@ -6966,7 +6966,24 @@ LocalInstantiationScope &Scope, const MultiLevelTemplateArgumentList &TemplateArgs); + llvm::Optional + SetupConstraintCheckingTemplateArgumentsAndScope( + FunctionDecl *FD, llvm::Optional> TemplateArgs, + LocalInstantiationScope &Scope); + + // Keep track of whether we are evaluating a constraint. + unsigned ConstraintEvaluationDepth = 0; + + class ConstraintEvalRAII { + Sema &S; + + public: + ConstraintEvalRAII(Sema &S) : S(S) { ++S.ConstraintEvaluationDepth; } + ~ConstraintEvalRAII() { --S.ConstraintEvaluationDepth; } + }; + public: + bool IsEvaluatingAConstraint() { return ConstraintEvaluationDepth > 0; } const NormalizedConstraint * getNormalizedAssociatedConstraints( NamedDecl *ConstrainedDecl, ArrayRef AssociatedConstraints); @@ -6996,8 +7013,10 @@ /// check (either a concept or a constrained entity). /// \param ConstraintExprs a list of constraint expressions, treated as if /// they were 'AND'ed together. - /// \param TemplateArgs the list of template arguments to substitute into the - /// constraint expression. + /// \param TemplateArgList the multi-level list of template arguments to + /// substitute into the constraint expression. This should be relative to the + /// top-level (hence multi-level), since we need to instantiate fully at the + /// time of checking. /// \param TemplateIDRange The source range of the template id that /// caused the constraints check. /// \param Satisfaction if true is returned, will contain details of the @@ -7007,7 +7026,40 @@ /// false otherwise. bool CheckConstraintSatisfaction( const NamedDecl *Template, ArrayRef ConstraintExprs, - ArrayRef TemplateArgs, + const MultiLevelTemplateArgumentList &TemplateArgList, + SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction) { + llvm::SmallVector Converted; + return CheckConstraintSatisfaction(Template, ConstraintExprs, Converted, + TemplateArgList, TemplateIDRange, + Satisfaction); + } + + /// \brief Check whether the given list of constraint expressions are + /// satisfied (as if in a 'conjunction') given template arguments. + /// Additionally, takes an empty list of Expressions which is populated with + /// the instantiated versions of the ConstraintExprs. + /// \param Template the template-like entity that triggered the constraints + /// check (either a concept or a constrained entity). + /// \param ConstraintExprs a list of constraint expressions, treated as if + /// they were 'AND'ed together. + /// \param ConvertedConstraints a out parameter that will get populated with + /// the instantiated version of the ConstraintExprs if we successfully checked + /// satisfaction. + /// \param TemplateArgList the multi-level list of template arguments to + /// substitute into the constraint expression. This should be relative to the + /// top-level (hence multi-level), since we need to instantiate fully at the + /// time of checking. + /// \param TemplateIDRange The source range of the template id that + /// caused the constraints check. + /// \param Satisfaction if true is returned, will contain details of the + /// satisfaction, with enough information to diagnose an unsatisfied + /// expression. + /// \returns true if an error occurred and satisfaction could not be checked, + /// false otherwise. + bool CheckConstraintSatisfaction( + const NamedDecl *Template, ArrayRef ConstraintExprs, + llvm::SmallVectorImpl &ConvertedConstraints, + const MultiLevelTemplateArgumentList &TemplateArgList, SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction); /// \brief Check whether the given non-dependent constraint expression is @@ -7043,9 +7095,9 @@ /// /// \returns true if the constrains are not satisfied or could not be checked /// for satisfaction, false if the constraints are satisfied. - bool EnsureTemplateArgumentListConstraints(TemplateDecl *Template, - ArrayRef TemplateArgs, - SourceRange TemplateIDRange); + bool EnsureTemplateArgumentListConstraints( + TemplateDecl *Template, MultiLevelTemplateArgumentList TemplateArgs, + SourceRange TemplateIDRange); /// \brief Emit diagnostics explaining why a constraint expression was deemed /// unsatisfied. @@ -8778,7 +8830,8 @@ MultiLevelTemplateArgumentList getTemplateInstantiationArgs( const NamedDecl *D, const TemplateArgumentList *Innermost = nullptr, - bool RelativeToPrimary = false, const FunctionDecl *Pattern = nullptr); + bool RelativeToPrimary = false, const FunctionDecl *Pattern = nullptr, + bool LookBeyondLambda = false, bool IncludeContainingStruct = false); /// A context in which code is being synthesized (where a source location /// alone is not sufficient to identify the context). This covers template @@ -9499,6 +9552,11 @@ ExtParameterInfoBuilder &ParamInfos); ExprResult SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs); + // Unlike the above, this evaluates constraints, which should only happen at + // 'constraint checking' time. + ExprResult + SubstConstraintExpr(Expr *E, + const MultiLevelTemplateArgumentList &TemplateArgs); /// Substitute the given template arguments into a list of /// expressions, expanding pack expansions if required. Index: clang/include/clang/Sema/Template.h =================================================================== --- clang/include/clang/Sema/Template.h +++ clang/include/clang/Sema/Template.h @@ -158,6 +158,14 @@ return !(*this)(Depth, Index).isNull(); } + bool isAnyArgInstantiationDependent() const { + for (ArgList List : TemplateArgumentLists) + for (const TemplateArgument &TA : List) + if (TA.isInstantiationDependent()) + return true; + return false; + } + /// Clear out a specific template argument. void setArgument(unsigned Depth, unsigned Index, TemplateArgument Arg) { @@ -197,6 +205,9 @@ const ArgList &getInnermost() const { return TemplateArgumentLists.front(); } + + /// Retrieve the outermost template argument list. + const ArgList &getOutermost() const { return TemplateArgumentLists.back(); } }; /// The context in which partial ordering of function templates occurs. Index: clang/lib/Sema/SemaConcept.cpp =================================================================== --- clang/lib/Sema/SemaConcept.cpp +++ clang/lib/Sema/SemaConcept.cpp @@ -30,6 +30,7 @@ namespace { class LogicalBinOp { + SourceLocation Loc; OverloadedOperatorKind Op = OO_None; const Expr *LHS = nullptr; const Expr *RHS = nullptr; @@ -40,12 +41,14 @@ Op = BinaryOperator::getOverloadedOperator(BO->getOpcode()); LHS = BO->getLHS(); RHS = BO->getRHS(); + Loc = BO->getExprLoc(); } else if (auto *OO = dyn_cast(E)) { // If OO is not || or && it might not have exactly 2 arguments. if (OO->getNumArgs() == 2) { Op = OO->getOperator(); LHS = OO->getArg(0); RHS = OO->getArg(1); + Loc = OO->getOperatorLoc(); } } } @@ -56,6 +59,22 @@ const Expr *getLHS() const { return LHS; } const Expr *getRHS() const { return RHS; } + + ExprResult recreateBinOp(Sema &SemaRef, ExprResult LHS) { + return recreateBinOp(SemaRef, LHS, const_cast(getRHS())); + } + + ExprResult recreateBinOp(Sema &SemaRef, ExprResult LHS, ExprResult RHS) { + assert((isAnd() || isOr()) && "Not the right kind of op?"); + assert((!LHS.isInvalid() && !RHS.isInvalid()) && "not good expressions?"); + assert(LHS.isUsable() && RHS.isUsable() && "Side not usable?"); + // We should just be able to 'normalize' these to the builtin Binary + // Operator, since that is how they are evaluated in constriant checks. + return BinaryOperator::Create(SemaRef.Context, LHS.get(), RHS.get(), + BinaryOperator::getOverloadedOpcode(Op), + SemaRef.Context.BoolTy, VK_PRValue, + OK_Ordinary, Loc, FPOptionsOverride{}); + } }; } @@ -122,16 +141,18 @@ } template -static bool +static ExprResult calculateConstraintSatisfaction(Sema &S, const Expr *ConstraintExpr, ConstraintSatisfaction &Satisfaction, AtomicEvaluator &&Evaluator) { ConstraintExpr = ConstraintExpr->IgnoreParenImpCasts(); if (LogicalBinOp BO = ConstraintExpr) { - if (calculateConstraintSatisfaction(S, BO.getLHS(), Satisfaction, - Evaluator)) - return true; + ExprResult LHSRes = calculateConstraintSatisfaction( + S, BO.getLHS(), Satisfaction, Evaluator); + + if (LHSRes.isInvalid()) + return ExprError(); bool IsLHSSatisfied = Satisfaction.IsSatisfied; @@ -142,7 +163,7 @@ // is checked. If that is satisfied, the disjunction is satisfied. // Otherwise, the disjunction is satisfied if and only if the second // operand is satisfied. - return false; + return LHSRes.isUsable() ? BO.recreateBinOp(S, LHSRes) : ExprEmpty(); if (BO.isAnd() && !IsLHSSatisfied) // [temp.constr.op] p2 @@ -151,12 +172,21 @@ // is checked. If that is not satisfied, the conjunction is not // satisfied. Otherwise, the conjunction is satisfied if and only if // the second operand is satisfied. - return false; + return LHSRes.isUsable() ? BO.recreateBinOp(S, LHSRes) : ExprEmpty(); - return calculateConstraintSatisfaction( + ExprResult RHSRes = calculateConstraintSatisfaction( S, BO.getRHS(), Satisfaction, std::forward(Evaluator)); + if (RHSRes.isInvalid()) + return ExprError(); + + if (!LHSRes.isUsable() || !RHSRes.isUsable()) + return ExprEmpty(); + return BO.recreateBinOp(S, LHSRes, RHSRes); } else if (auto *C = dyn_cast(ConstraintExpr)) { - return calculateConstraintSatisfaction(S, C->getSubExpr(), Satisfaction, + // These aren't evaluated, so we don't care about cleanups, so we can just + // evaluate these as if the cleanups didn't exist. + return calculateConstraintSatisfaction( + S, C->getSubExpr(), Satisfaction, std::forward(Evaluator)); } @@ -164,11 +194,11 @@ ExprResult SubstitutedAtomicExpr = Evaluator(ConstraintExpr); if (SubstitutedAtomicExpr.isInvalid()) - return true; + return ExprError(); if (!SubstitutedAtomicExpr.isUsable()) // Evaluator has decided satisfaction without yielding an expression. - return false; + return ExprEmpty(); EnterExpressionEvaluationContext ConstantEvaluated( S, Sema::ExpressionEvaluationContext::ConstantEvaluated); @@ -185,7 +215,7 @@ << SubstitutedAtomicExpr.get()->getSourceRange(); for (const PartialDiagnosticAt &PDiag : EvaluationDiags) S.Diag(PDiag.first, PDiag.second); - return true; + return ExprError(); } assert(EvalResult.Val.isInt() && @@ -195,13 +225,13 @@ Satisfaction.Details.emplace_back(ConstraintExpr, SubstitutedAtomicExpr.get()); - return false; + return SubstitutedAtomicExpr; } -static bool calculateConstraintSatisfaction( - Sema &S, const NamedDecl *Template, ArrayRef TemplateArgs, - SourceLocation TemplateNameLoc, MultiLevelTemplateArgumentList &MLTAL, - const Expr *ConstraintExpr, ConstraintSatisfaction &Satisfaction) { +static ExprResult calculateConstraintSatisfaction( + Sema &S, const NamedDecl *Template, SourceLocation TemplateNameLoc, + const MultiLevelTemplateArgumentList &MLTAL, const Expr *ConstraintExpr, + ConstraintSatisfaction &Satisfaction) { return calculateConstraintSatisfaction( S, ConstraintExpr, Satisfaction, [&](const Expr *AtomicExpr) { EnterExpressionEvaluationContext ConstantEvaluated( @@ -219,8 +249,8 @@ return ExprError(); // We do not want error diagnostics escaping here. Sema::SFINAETrap Trap(S); - SubstitutedExpression = S.SubstExpr(const_cast(AtomicExpr), - MLTAL); + SubstitutedExpression = + S.SubstConstraintExpr(const_cast(AtomicExpr), MLTAL); // Substitution might have stripped off a contextual conversion to // bool if this is the operand of an '&&' or '||'. For example, we // might lose an lvalue-to-rvalue conversion here. If so, put it back @@ -268,56 +298,70 @@ }); } -static bool CheckConstraintSatisfaction(Sema &S, const NamedDecl *Template, - ArrayRef ConstraintExprs, - ArrayRef TemplateArgs, - SourceRange TemplateIDRange, - ConstraintSatisfaction &Satisfaction) { +static bool CheckConstraintSatisfaction( + Sema &S, const NamedDecl *Template, ArrayRef ConstraintExprs, + llvm::SmallVectorImpl &Converted, + const MultiLevelTemplateArgumentList &TemplateArgsList, + SourceRange TemplateIDRange, ConstraintSatisfaction &Satisfaction) { if (ConstraintExprs.empty()) { Satisfaction.IsSatisfied = true; return false; } - for (auto& Arg : TemplateArgs) - if (Arg.isInstantiationDependent()) { - // No need to check satisfaction for dependent constraint expressions. - Satisfaction.IsSatisfied = true; - return false; - } + if (TemplateArgsList.isAnyArgInstantiationDependent()) { + // No need to check satisfaction for dependent constraint expressions. + Satisfaction.IsSatisfied = true; + return false; + } + + ArrayRef TemplateArgs = + TemplateArgsList.getNumSubstitutedLevels() > 0 + ? TemplateArgsList.getOutermost() + : ArrayRef{}; - Sema::InstantiatingTemplate Inst(S, TemplateIDRange.getBegin(), + Sema::InstantiatingTemplate Inst( + S, TemplateIDRange.getBegin(), Sema::InstantiatingTemplate::ConstraintsCheck{}, const_cast(Template), TemplateArgs, TemplateIDRange); if (Inst.isInvalid()) return true; - MultiLevelTemplateArgumentList MLTAL; - MLTAL.addOuterTemplateArguments(TemplateArgs); - for (const Expr *ConstraintExpr : ConstraintExprs) { - if (calculateConstraintSatisfaction(S, Template, TemplateArgs, - TemplateIDRange.getBegin(), MLTAL, - ConstraintExpr, Satisfaction)) + ExprResult Res = calculateConstraintSatisfaction( + S, Template, TemplateIDRange.getBegin(), TemplateArgsList, + ConstraintExpr, Satisfaction); + if (Res.isInvalid()) return true; - if (!Satisfaction.IsSatisfied) - // [temp.constr.op] p2 + + Converted.push_back(Res.get()); + if (!Satisfaction.IsSatisfied) { + // Backfill the 'converted' list with nulls so we can keep the Converted + Converted.append(ConstraintExprs.size() - Converted.size(), nullptr); + // and unconverted lists in sync. [temp.constr.op] p2 // [...] To determine if a conjunction is satisfied, the satisfaction // of the first operand is checked. If that is not satisfied, the // conjunction is not satisfied. [...] return false; + } } return false; } bool Sema::CheckConstraintSatisfaction( const NamedDecl *Template, ArrayRef ConstraintExprs, - ArrayRef TemplateArgs, SourceRange TemplateIDRange, - ConstraintSatisfaction &OutSatisfaction) { + llvm::SmallVectorImpl &ConvertedConstraints, + const MultiLevelTemplateArgumentList &TemplateArgsList, + SourceRange TemplateIDRange, ConstraintSatisfaction &OutSatisfaction) { if (ConstraintExprs.empty()) { OutSatisfaction.IsSatisfied = true; return false; } + ArrayRef TemplateArgs = + TemplateArgsList.getNumSubstitutedLevels() > 0 + ? TemplateArgsList.getOutermost() + : ArrayRef{}; + llvm::FoldingSetNodeID ID; void *InsertPos; ConstraintSatisfaction *Satisfaction = nullptr; @@ -334,8 +378,8 @@ Satisfaction = &OutSatisfaction; } if (::CheckConstraintSatisfaction(*this, Template, ConstraintExprs, - TemplateArgs, TemplateIDRange, - *Satisfaction)) { + ConvertedConstraints, TemplateArgsList, + TemplateIDRange, *Satisfaction)) { if (ShouldCache) delete Satisfaction; return true; @@ -353,20 +397,83 @@ bool Sema::CheckConstraintSatisfaction(const Expr *ConstraintExpr, ConstraintSatisfaction &Satisfaction) { return calculateConstraintSatisfaction( - *this, ConstraintExpr, Satisfaction, - [](const Expr *AtomicExpr) -> ExprResult { - return ExprResult(const_cast(AtomicExpr)); - }); + *this, ConstraintExpr, Satisfaction, + [](const Expr *AtomicExpr) -> ExprResult { + return ExprResult(const_cast(AtomicExpr)); + }) + .isInvalid(); +} + +// This function collects all of the template arguments for the purposes of +// constraint-instantiation and checking. +llvm::Optional +Sema::SetupConstraintCheckingTemplateArgumentsAndScope( + FunctionDecl *FD, llvm::Optional> TemplateArgs, + LocalInstantiationScope &Scope) { + MultiLevelTemplateArgumentList MLTAL; + + // Collect the list of template arguments relative to the 'primary' template. + // We need the entire list, since the constraint is completely uninstantiated + // at this point. + MLTAL = getTemplateInstantiationArgs(FD, nullptr, /*RelativeToPrimary*/ true, + /*Pattern*/ nullptr, + /*LookBeyondLambda*/ true); + + if (FD->isTemplateInstantiation() && FD->getPrimaryTemplate()) { + FunctionTemplateDecl *PrimaryTemplate = FD->getPrimaryTemplate(); + InstantiatingTemplate Inst( + *this, FD->getPointOfInstantiation(), + InstantiatingTemplate::ConstraintsCheck{}, PrimaryTemplate, + TemplateArgs ? *TemplateArgs : ArrayRef{}, + SourceRange()); + if (Inst.isInvalid()) + return {}; + + // addInstantiatedParametersToScope creates a map of 'uninstantiated' to + // 'instantiated' parameters and adds it to the context. For the case where + // this function is a template being instantiated NOW, we also need to add + // the list of current template arguments to the list so that they also can + // be picked out of the map. + if (TemplateArgs) { + MultiLevelTemplateArgumentList JustTemplArgs( + *FD->getTemplateSpecializationArgs()); + if (addInstantiatedParametersToScope( + FD, PrimaryTemplate->getTemplatedDecl(), Scope, JustTemplArgs)) + return {}; + } + + // If this is a member function, make sure we get the parameters that + // reference the original primary template. + if (const auto *FromMemTempl = + PrimaryTemplate->getInstantiatedFromMemberTemplate()) { + if (addInstantiatedParametersToScope(FD, FromMemTempl->getTemplatedDecl(), + Scope, MLTAL)) + return {}; + } + } + + return MLTAL; } bool Sema::CheckFunctionConstraints(const FunctionDecl *FD, ConstraintSatisfaction &Satisfaction, SourceLocation UsageLoc) { - const Expr *RC = FD->getTrailingRequiresClause(); - if (RC->isInstantiationDependent()) { + // Don't check constraints if the function is dependent. Also don't check if + // this is a function template specialization, as the call to + // CheckinstantiatedFunctionTemplateConstraints after this will check it + // better. + if (FD->isDependentContext() || + FD->getTemplatedKind() == + FunctionDecl::TK_FunctionTemplateSpecialization) { Satisfaction.IsSatisfied = true; return false; } + + LocalInstantiationScope Scope(*this); + llvm::Optional MLTAL = + SetupConstraintCheckingTemplateArgumentsAndScope( + const_cast(FD), {}, Scope); + Qualifiers ThisQuals; CXXRecordDecl *Record = nullptr; if (auto *Method = dyn_cast(FD)) { @@ -377,14 +484,27 @@ // We substitute with empty arguments in order to rebuild the atomic // constraint in a constant-evaluated context. // FIXME: Should this be a dedicated TreeTransform? - return CheckConstraintSatisfaction( - FD, {RC}, /*TemplateArgs=*/{}, - SourceRange(UsageLoc.isValid() ? UsageLoc : FD->getLocation()), - Satisfaction); + const Expr *RC = FD->getTrailingRequiresClause(); + llvm::SmallVector Converted; + + if (CheckConstraintSatisfaction( + FD, {RC}, Converted, *MLTAL, + SourceRange(UsageLoc.isValid() ? UsageLoc : FD->getLocation()), + Satisfaction)) + return true; + + // Attn Reviewers: we need to do this for the function constraints for + // comparison of constraints to work, but do we also need to do it for + // CheckInstantiatedFunctionConstraints? That one is more difficult, but we + // seem to always just pick up the constraints from the primary template. + assert(Converted.size() <= 1 && "Got more expressions converted?"); + if (!Converted.empty() && Converted[0] != nullptr) + const_cast(FD)->setTrailingRequiresClause(Converted[0]); + return false; } bool Sema::EnsureTemplateArgumentListConstraints( - TemplateDecl *TD, ArrayRef TemplateArgs, + TemplateDecl *TD, MultiLevelTemplateArgumentList TemplateArgs, SourceRange TemplateIDRange) { ConstraintSatisfaction Satisfaction; llvm::SmallVector AssociatedConstraints; @@ -397,7 +517,8 @@ SmallString<128> TemplateArgString; TemplateArgString = " "; TemplateArgString += getTemplateArgumentBindingsText( - TD->getTemplateParameters(), TemplateArgs.data(), TemplateArgs.size()); + TD->getTemplateParameters(), TemplateArgs.getInnermost().data(), + TemplateArgs.getInnermost().size()); Diag(TemplateIDRange.getBegin(), diag::err_template_arg_list_constraints_not_satisfied) @@ -429,21 +550,13 @@ Sema::ContextRAII savedContext(*this, Decl); LocalInstantiationScope Scope(*this); - // If this is not an explicit specialization - we need to get the instantiated - // version of the template arguments and add them to scope for the - // substitution. - if (Decl->isTemplateInstantiation()) { - InstantiatingTemplate Inst(*this, Decl->getPointOfInstantiation(), - InstantiatingTemplate::ConstraintsCheck{}, Decl->getPrimaryTemplate(), - TemplateArgs, SourceRange()); - if (Inst.isInvalid()) - return true; - MultiLevelTemplateArgumentList MLTAL( - *Decl->getTemplateSpecializationArgs()); - if (addInstantiatedParametersToScope( - Decl, Decl->getPrimaryTemplate()->getTemplatedDecl(), Scope, MLTAL)) - return true; - } + Optional MLTAL = + SetupConstraintCheckingTemplateArgumentsAndScope(Decl, TemplateArgs, + Scope); + + if (!MLTAL) + return true; + Qualifiers ThisQuals; CXXRecordDecl *Record = nullptr; if (auto *Method = dyn_cast(Decl)) { @@ -451,7 +564,8 @@ Record = Method->getParent(); } CXXThisScopeRAII ThisScope(*this, Record, ThisQuals, Record != nullptr); - return CheckConstraintSatisfaction(Template, TemplateAC, TemplateArgs, + llvm::SmallVector Converted; + return CheckConstraintSatisfaction(Template, TemplateAC, Converted, *MLTAL, PointOfInstantiation, Satisfaction); } Index: clang/lib/Sema/SemaTemplate.cpp =================================================================== --- clang/lib/Sema/SemaTemplate.cpp +++ clang/lib/Sema/SemaTemplate.cpp @@ -4698,9 +4698,11 @@ bool AreArgsDependent = TemplateSpecializationType::anyDependentTemplateArguments(*TemplateArgs, Converted); + MultiLevelTemplateArgumentList MLTAL; + MLTAL.addOuterTemplateArguments(Converted); if (!AreArgsDependent && CheckConstraintSatisfaction( - NamedConcept, {NamedConcept->getConstraintExpr()}, Converted, + NamedConcept, {NamedConcept->getConstraintExpr()}, MLTAL, SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameInfo.getLoc(), TemplateArgs->getRAngleLoc()), Satisfaction)) @@ -5560,6 +5562,7 @@ if (Inst.isInvalid()) return true; + ConstraintEvalRAII EvalRAII(*this); TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted); Params = SubstTemplateParams(Params, CurContext, MultiLevelTemplateArgumentList(TemplateArgs)); @@ -5917,13 +5920,20 @@ if (UpdateArgsWithConversions) TemplateArgs = std::move(NewArgs); - if (!PartialTemplateArgs && - EnsureTemplateArgumentListConstraints( - Template, Converted, SourceRange(TemplateLoc, - TemplateArgs.getRAngleLoc()))) { - if (ConstraintsNotSatisfied) - *ConstraintsNotSatisfied = true; - return true; + if (!PartialTemplateArgs) { + TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack, + Converted); + MultiLevelTemplateArgumentList MLTAL = getTemplateInstantiationArgs( + Template, &StackTemplateArgs, /*RelativeToPrimary*/ true, + /*Pattern*/ nullptr, + /*LookBeyondLambda*/ true, /*IncludeContainingStruct*/ true); + if (EnsureTemplateArgumentListConstraints( + Template, MLTAL, + SourceRange(TemplateLoc, TemplateArgs.getRAngleLoc()))) { + if (ConstraintsNotSatisfied) + *ConstraintsNotSatisfied = true; + return true; + } } return false; @@ -7453,7 +7463,9 @@ // are not considered. if (ParamsAC.empty()) return false; + Template->getAssociatedConstraints(TemplateAC); + bool IsParamAtLeastAsConstrained; if (IsAtLeastAsConstrained(Param, ParamsAC, Template, TemplateAC, IsParamAtLeastAsConstrained)) Index: clang/lib/Sema/SemaTemplateDeduction.cpp =================================================================== --- clang/lib/Sema/SemaTemplateDeduction.cpp +++ clang/lib/Sema/SemaTemplateDeduction.cpp @@ -2791,8 +2791,10 @@ TemplateDeductionInfo& Info) { llvm::SmallVector AssociatedConstraints; Template->getAssociatedConstraints(AssociatedConstraints); - if (S.CheckConstraintSatisfaction(Template, AssociatedConstraints, - DeducedArgs, Info.getLocation(), + MultiLevelTemplateArgumentList MLTAL; + MLTAL.addOuterTemplateArguments(DeducedArgs); + if (S.CheckConstraintSatisfaction(Template, AssociatedConstraints, MLTAL, + Info.getLocation(), Info.AssociatedConstraintsSatisfaction) || !Info.AssociatedConstraintsSatisfaction.IsSatisfied) { Info.reset(TemplateArgumentList::CreateCopy(S.Context, DeducedArgs)); @@ -4572,8 +4574,11 @@ if (S.CheckTemplateArgumentList(Concept, SourceLocation(), TemplateArgs, /*PartialTemplateArgs=*/false, Converted)) return Sema::DAR_FailedAlreadyDiagnosed; + + MultiLevelTemplateArgumentList MLTAL; + MLTAL.addOuterTemplateArguments(Converted); if (S.CheckConstraintSatisfaction(Concept, {Concept->getConstraintExpr()}, - Converted, TypeLoc.getLocalSourceRange(), + MLTAL, TypeLoc.getLocalSourceRange(), Satisfaction)) return Sema::DAR_FailedAlreadyDiagnosed; if (!Satisfaction.IsSatisfied) { Index: clang/lib/Sema/SemaTemplateInstantiate.cpp =================================================================== --- clang/lib/Sema/SemaTemplateInstantiate.cpp +++ clang/lib/Sema/SemaTemplateInstantiate.cpp @@ -55,9 +55,18 @@ /// instantiating the definition of the given declaration, \p D. This is /// used to determine the proper set of template instantiation arguments for /// friend function template specializations. +/// +/// \param LookBeyondLambda Indicates that this collection of arguments should +/// continue looking when it encounters a lambda generic call operator. +/// +/// \param IncludeContainingStructArgs Indicates that this collection of +/// arguments should include arguments for any class template that this +/// declaration is included inside of. + MultiLevelTemplateArgumentList Sema::getTemplateInstantiationArgs( const NamedDecl *D, const TemplateArgumentList *Innermost, - bool RelativeToPrimary, const FunctionDecl *Pattern) { + bool RelativeToPrimary, const FunctionDecl *Pattern, bool LookBeyondLambda, + bool IncludeContainingStructArgs) { // Accumulate the set of template argument lists in this structure. MultiLevelTemplateArgumentList Result; @@ -153,11 +162,13 @@ break; // If this function is a generic lambda specialization, we are done. - if (isGenericLambdaCallOperatorOrStaticInvokerSpecialization(Function)) + if (!LookBeyondLambda && + isGenericLambdaCallOperatorOrStaticInvokerSpecialization(Function)) break; } else if (Function->getDescribedFunctionTemplate()) { - assert(Result.getNumSubstitutedLevels() == 0 && + assert((IncludeContainingStructArgs || + Result.getNumSubstitutedLevels() == 0) && "Outer template not instantiated?"); } @@ -174,10 +185,18 @@ } } else if (const auto *Rec = dyn_cast(Ctx)) { if (ClassTemplateDecl *ClassTemplate = Rec->getDescribedClassTemplate()) { - assert(Result.getNumSubstitutedLevels() == 0 && + assert((IncludeContainingStructArgs || + Result.getNumSubstitutedLevels() == 0) && "Outer template not instantiated?"); if (ClassTemplate->isMemberSpecialization()) break; + if (IncludeContainingStructArgs) { + QualType RecordType = Context.getTypeDeclType(Rec); + QualType Injected = cast(RecordType) + ->getInjectedSpecializationType(); + const auto *InjectedType = cast(Injected); + Result.addOuterTemplateArguments(InjectedType->template_arguments()); + } } } @@ -2304,6 +2323,17 @@ const MultiLevelTemplateArgumentList &TemplateArgs) { const ASTTemplateArgumentListInfo *TemplArgInfo = TC->getTemplateArgsAsWritten(); + + // If we're not checking a constraint, we shouldn't be instantiating the type + // constraint, so we should just create a copy of the previous one. + if (!IsEvaluatingAConstraint()) { + Inst->setTypeConstraint(TC->getNestedNameSpecifierLoc(), + TC->getConceptNameInfo(), TC->getNamedConcept(), + TC->getNamedConcept(), TemplArgInfo, + TC->getImmediatelyDeclaredConstraint()); + return false; + } + TemplateArgumentListInfo InstArgs; if (TemplArgInfo) { @@ -3488,6 +3518,14 @@ return Instantiator.TransformExpr(E); } +ExprResult +Sema::SubstConstraintExpr(Expr *E, + const MultiLevelTemplateArgumentList &TemplateArgs) { + + ConstraintEvalRAII EvalRAII(*this); + return SubstExpr(E, TemplateArgs); +} + ExprResult Sema::SubstInitializer(Expr *Init, const MultiLevelTemplateArgumentList &TemplateArgs, bool CXXDirectInit) { Index: clang/lib/Sema/SemaTemplateInstantiateDecl.cpp =================================================================== --- clang/lib/Sema/SemaTemplateInstantiateDecl.cpp +++ clang/lib/Sema/SemaTemplateInstantiateDecl.cpp @@ -2037,19 +2037,7 @@ return nullptr; } - // FIXME: Concepts: Do not substitute into constraint expressions Expr *TrailingRequiresClause = D->getTrailingRequiresClause(); - if (TrailingRequiresClause) { - EnterExpressionEvaluationContext ConstantEvaluated( - SemaRef, Sema::ExpressionEvaluationContext::Unevaluated); - ExprResult SubstRC = SemaRef.SubstExpr(TrailingRequiresClause, - TemplateArgs); - if (SubstRC.isInvalid()) - return nullptr; - TrailingRequiresClause = SubstRC.get(); - if (!SemaRef.CheckConstraintExpression(TrailingRequiresClause)) - return nullptr; - } // If we're instantiating a local function declaration, put the result // in the enclosing namespace; otherwise we need to find the instantiated @@ -2394,22 +2382,7 @@ return nullptr; } - // FIXME: Concepts: Do not substitute into constraint expressions Expr *TrailingRequiresClause = D->getTrailingRequiresClause(); - if (TrailingRequiresClause) { - EnterExpressionEvaluationContext ConstantEvaluated( - SemaRef, Sema::ExpressionEvaluationContext::Unevaluated); - auto *ThisContext = dyn_cast_or_null(Owner); - Sema::CXXThisScopeRAII ThisScope(SemaRef, ThisContext, - D->getMethodQualifiers(), ThisContext); - ExprResult SubstRC = SemaRef.SubstExpr(TrailingRequiresClause, - TemplateArgs); - if (SubstRC.isInvalid()) - return nullptr; - TrailingRequiresClause = SubstRC.get(); - if (!SemaRef.CheckConstraintExpression(TrailingRequiresClause)) - return nullptr; - } DeclContext *DC = Owner; if (isFriend) { @@ -2741,9 +2714,6 @@ // Invented template parameter type constraints will be instantiated with // the corresponding auto-typed parameter as it might reference other // parameters. - - // TODO: Concepts: do not instantiate the constraint (delayed constraint - // substitution) if (SemaRef.SubstTypeConstraint(Inst, TC, TemplateArgs)) return nullptr; } @@ -3986,18 +3956,7 @@ if (Invalid) return nullptr; - // FIXME: Concepts: Substitution into requires clause should only happen when - // checking satisfaction. - Expr *InstRequiresClause = nullptr; - if (Expr *E = L->getRequiresClause()) { - EnterExpressionEvaluationContext ConstantEvaluated( - SemaRef, Sema::ExpressionEvaluationContext::Unevaluated); - ExprResult Res = SemaRef.SubstExpr(E, TemplateArgs); - if (Res.isInvalid() || !Res.isUsable()) { - return nullptr; - } - InstRequiresClause = Res.get(); - } + Expr *InstRequiresClause = L->getRequiresClause(); TemplateParameterList *InstL = TemplateParameterList::Create(SemaRef.Context, L->getTemplateLoc(), Index: clang/lib/Sema/TreeTransform.h =================================================================== --- clang/lib/Sema/TreeTransform.h +++ clang/lib/Sema/TreeTransform.h @@ -12974,11 +12974,8 @@ } // Transform the trailing requires clause - ExprResult NewTrailingRequiresClause; - if (Expr *TRC = E->getCallOperator()->getTrailingRequiresClause()) - // FIXME: Concepts: Substitution into requires clause should only happen - // when checking satisfaction. - NewTrailingRequiresClause = getDerived().TransformExpr(TRC); + ExprResult NewTrailingRequiresClause = + E->getCallOperator()->getTrailingRequiresClause(); // Create the local class that will describe the lambda. Index: clang/test/CXX/temp/temp.constr/temp.constr.constr/non-function-templates.cpp =================================================================== --- clang/test/CXX/temp/temp.constr/temp.constr.constr/non-function-templates.cpp +++ clang/test/CXX/temp/temp.constr/temp.constr.constr/non-function-templates.cpp @@ -90,3 +90,24 @@ static_assert(C{}); // expected-note{{while checking constraint satisfaction for template 'C' required here}} static_assert(D{}); // expected-note{{while checking constraint satisfaction for template 'D' required here}} + +// Test the delayed instantiation, the 'foo' implementation shouldn't cause the +// constraint failure(or crash!) until the use to create 'y'. +namespace DelayedInst { +template +struct AAA { + template + requires(sizeof(T) == I) // expected-note {{because 'sizeof(int) == 5U' (4 == 5) evaluated to false}} + struct B { + static constexpr int a = 0; + }; + + static constexpr auto foo() { + return B::a; // expected-error{{constraints not satisfied for class template 'B' [with T = int]}} + } +}; + +constexpr auto x = AAA<4>::foo(); +constexpr auto y = AAA<5>::foo(); // expected-note {{in instantiation of member function 'DelayedInst::AAA<5>::foo' requested here}} + +} // namespace DelayedInst Index: clang/test/SemaTemplate/deferred-concept-inst.cpp =================================================================== --- /dev/null +++ clang/test/SemaTemplate/deferred-concept-inst.cpp @@ -0,0 +1,23 @@ +// RUN: %clang_cc1 -std=c++2a -x c++ %s -verify -Wno-unused-value +// expected-no-diagnostics + +namespace GithubBug44178 { +template +struct CRTP { + void call_foo() requires + requires(D &v) { v.foo(); } + { + static_cast(this)->foo(); + } +}; + +struct Test : public CRTP { + void foo() {} +}; + +int main() { + Test t; + t.call_foo(); + return 0; +} +} // namespace GithubBug44178 Index: clang/test/SemaTemplate/instantiate-requires-clause.cpp =================================================================== --- clang/test/SemaTemplate/instantiate-requires-clause.cpp +++ clang/test/SemaTemplate/instantiate-requires-clause.cpp @@ -40,6 +40,18 @@ static_assert(S::f(1)); +// Similar to the 'S' test, but tries to use 'U' in the requires clause. +template +struct S1 { + // expected-note@+3 {{candidate template ignored: constraints not satisfied [with U = int]}} + // expected-note@+2 {{because substituted constraint expression is ill-formed: type 'int' cannot be used prior to '::' because it has no members}} + template + static constexpr auto f(U const index) requires(U::foo) { return true; } +}; + +// expected-error@+1 {{no matching function for call to 'f'}} +static_assert(S1::f(1)); + constexpr auto value = 0; template Index: clang/test/SemaTemplate/trailing-return-short-circuit.cpp =================================================================== --- /dev/null +++ clang/test/SemaTemplate/trailing-return-short-circuit.cpp @@ -0,0 +1,61 @@ +// RUN: %clang_cc1 -std=c++20 -verify %s + +template +requires(sizeof(T) > 2) || T::value // #FOO_REQ + void Foo(T){}; // #FOO + +template + void TrailingReturn(T) // #TRAILING + requires(sizeof(T) > 2) || // #TRAILING_REQ + T::value{}; // #TRAILING_REQ_VAL +template +struct HasValue { + static constexpr bool value = B; +}; +static_assert(sizeof(HasValue) <= 2); + +template +struct HasValueLarge { + static constexpr bool value = B; + int I; +}; +static_assert(sizeof(HasValueLarge) > 2); + +void usage() { + // Passes the 1st check, short-circuit so the 2nd ::value is not evaluated. + Foo(1.0); + TrailingReturn(1.0); + + // Fails the 1st check, but has a ::value, so the check happens correctly. + Foo(HasValue{}); + TrailingReturn(HasValue{}); + + // Passes the 1st check, but would have passed the 2nd one. + Foo(HasValueLarge{}); + TrailingReturn(HasValueLarge{}); + + // Fails the 1st check, fails 2nd because there is no ::value. + Foo(true); + // expected-error@-1{{no matching function for call to 'Foo'}} + // expected-note@#FOO{{candidate template ignored: constraints not satisfied [with T = bool]}} + // expected-note@#FOO_REQ{{because 'sizeof(_Bool) > 2' (1 > 2) evaluated to false}} + // expected-note@#FOO_REQ{{because substituted constraint expression is ill-formed: type 'bool' cannot be used prior to '::' because it has no members}} + + TrailingReturn(true); + // expected-error@-1{{no matching function for call to 'TrailingReturn'}} + // expected-note@#TRAILING{{candidate template ignored: constraints not satisfied [with T = bool]}} + // expected-note@#TRAILING_REQ{{because 'sizeof(_Bool) > 2' (1 > 2) evaluated to false}} + // expected-note@#TRAILING_REQ_VAL{{because substituted constraint expression is ill-formed: type 'bool' cannot be used prior to '::' because it has no members}} + + // Fails the 1st check, fails 2nd because ::value is false. + Foo(HasValue{}); + // expected-error@-1 {{no matching function for call to 'Foo'}} + // expected-note@#FOO{{candidate template ignored: constraints not satisfied [with T = HasValue]}} + // expected-note@#FOO_REQ{{because 'sizeof(HasValue) > 2' (1 > 2) evaluated to false}} + // expected-note@#FOO_REQ{{and 'HasValue::value' evaluated to false}} + TrailingReturn(HasValue{}); + // expected-error@-1 {{no matching function for call to 'TrailingReturn'}} + // expected-note@#TRAILING{{candidate template ignored: constraints not satisfied [with T = HasValue]}} + // expected-note@#TRAILING_REQ{{because 'sizeof(HasValue) > 2' (1 > 2) evaluated to false}} + // expected-note@#TRAILING_REQ_VAL{{and 'HasValue::value' evaluated to false}} +}