llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Ilya Biryukov (ilya-biryukov) <details> <summary>Changes</summary> ... and only look at equivalence of substituted expressions, not results of constraint satisfaction. Fixes #<!-- -->74314. There is already some existing machinery for that in `TemplateInstantiator` and `Sema` exposed separate functions for substituting expressions with intention to do that: - `Sema::SubstExpr` should not evaluate constraints. - `Sema::SubstConstraintExpr` should. However, both functions used to be equivalent. This commit changes the former to actually avoid calculating constraint satisfaction and uses it in the code path that matches definition and declaration. --- Full diff: https://github.com/llvm/llvm-project/pull/74490.diff 4 Files Affected: - (modified) clang/include/clang/Sema/Template.h (+1) - (modified) clang/lib/Sema/SemaConcept.cpp (+8-7) - (modified) clang/lib/Sema/SemaTemplateInstantiate.cpp (+8) - (modified) clang/test/SemaTemplate/concepts-out-of-line-def.cpp (+21) ``````````diff diff --git a/clang/include/clang/Sema/Template.h b/clang/include/clang/Sema/Template.h index 2a553054a0ce5..ce44aca797b0f 100644 --- a/clang/include/clang/Sema/Template.h +++ b/clang/include/clang/Sema/Template.h @@ -564,6 +564,7 @@ enum class TemplateSubstitutionKind : char { const MultiLevelTemplateArgumentList &TemplateArgs; Sema::LateInstantiatedAttrVec* LateAttrs = nullptr; LocalInstantiationScope *StartingScope = nullptr; + // Whether to evaluate the C++20 constraints or simply substitute into them. bool EvaluateConstraints = true; /// A list of out-of-line class template partial diff --git a/clang/lib/Sema/SemaConcept.cpp b/clang/lib/Sema/SemaConcept.cpp index 719c6aab74e01..be3541573377b 100644 --- a/clang/lib/Sema/SemaConcept.cpp +++ b/clang/lib/Sema/SemaConcept.cpp @@ -771,10 +771,9 @@ namespace { }; } // namespace -static const Expr * -SubstituteConstraintExpression(Sema &S, - const Sema::TemplateCompareNewDeclInfo &DeclInfo, - const Expr *ConstrExpr) { +static const Expr *SubstituteConstraintExpressionWithoutSatisfaction( + Sema &S, const Sema::TemplateCompareNewDeclInfo &DeclInfo, + const Expr *ConstrExpr) { MultiLevelTemplateArgumentList MLTAL = S.getTemplateInstantiationArgs( DeclInfo.getDecl(), DeclInfo.getLexicalDeclContext(), /*Final=*/false, /*Innermost=*/nullptr, @@ -798,7 +797,7 @@ SubstituteConstraintExpression(Sema &S, if (auto *RD = dyn_cast<CXXRecordDecl>(DeclInfo.getDeclContext())) ThisScope.emplace(S, const_cast<CXXRecordDecl *>(RD), Qualifiers()); ExprResult SubstConstr = - S.SubstConstraintExpr(const_cast<clang::Expr *>(ConstrExpr), MLTAL); + S.SubstExpr(const_cast<clang::Expr *>(ConstrExpr), MLTAL); if (SFINAE.hasErrorOccurred() || !SubstConstr.isUsable()) return nullptr; return SubstConstr.get(); @@ -814,12 +813,14 @@ bool Sema::AreConstraintExpressionsEqual(const NamedDecl *Old, if (Old && !New.isInvalid() && !New.ContainsDecl(Old) && Old->getLexicalDeclContext() != New.getLexicalDeclContext()) { if (const Expr *SubstConstr = - SubstituteConstraintExpression(*this, Old, OldConstr)) + SubstituteConstraintExpressionWithoutSatisfaction(*this, Old, + OldConstr)) OldConstr = SubstConstr; else return false; if (const Expr *SubstConstr = - SubstituteConstraintExpression(*this, New, NewConstr)) + SubstituteConstraintExpressionWithoutSatisfaction(*this, New, + NewConstr)) NewConstr = SubstConstr; else return false; diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp index 6ad70109c8cee..971a4c99add0c 100644 --- a/clang/lib/Sema/SemaTemplateInstantiate.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp @@ -1186,6 +1186,7 @@ namespace { const MultiLevelTemplateArgumentList &TemplateArgs; SourceLocation Loc; DeclarationName Entity; + // Whether to evaluate the C++20 constraints or simply substitute into them. bool EvaluateConstraints = true; public: @@ -2489,6 +2490,12 @@ TemplateInstantiator::TransformNestedRequirement( Req->getConstraintExpr()->getBeginLoc(), Req, Sema::InstantiatingTemplate::ConstraintsCheck{}, Req->getConstraintExpr()->getSourceRange()); + if (!getEvaluateConstraints()) { + ExprResult TransConstraint = TransformExpr(Req->getConstraintExpr()); + if (TransConstraint.isInvalid() || !TransConstraint.get()) + return nullptr; + return RebuildNestedRequirement(TransConstraint.get()); + } ExprResult TransConstraint; ConstraintSatisfaction Satisfaction; @@ -4077,6 +4084,7 @@ Sema::SubstExpr(Expr *E, const MultiLevelTemplateArgumentList &TemplateArgs) { TemplateInstantiator Instantiator(*this, TemplateArgs, SourceLocation(), DeclarationName()); + Instantiator.setEvaluateConstraints(false); return Instantiator.TransformExpr(E); } diff --git a/clang/test/SemaTemplate/concepts-out-of-line-def.cpp b/clang/test/SemaTemplate/concepts-out-of-line-def.cpp index f134394615fb2..7e79eeb6d279a 100644 --- a/clang/test/SemaTemplate/concepts-out-of-line-def.cpp +++ b/clang/test/SemaTemplate/concepts-out-of-line-def.cpp @@ -504,3 +504,24 @@ struct bar { bar<int> x; } // namespace GH61763 + +namespace GH74314 { +template <class T, class U> constexpr bool is_same_v = __is_same(T, U); +template <class T, class U> constexpr bool is_not_same_v = !__is_same(T, U); + +template <class Result> +concept something_interesting = requires { + true; + requires is_same_v<int, Result>; +}; + +template <class T> +struct X { + void foo() requires requires { requires is_not_same_v<T, int>; }; +}; + +template <class T> +void X<T>::foo() requires requires { requires something_interesting<T>; } {} +// expected-error@-1{{definition of 'foo' does not match any declaration}} +// expected-note@*{{}} +} // namespace GH74314 \ No newline at end of file `````````` </details> https://github.com/llvm/llvm-project/pull/74490 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
