llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-clang Author: Younan Zhang (zyn0217) <details> <summary>Changes</summary> When substituting for rewrite purposes, as in rebuilding constraints for a synthesized deduction guide, it assumed that packs were in `PackExpansion*` form, such that the instantiator could extract a pattern. For type aliases CTAD, while rebuilding their associated constraints, we rebuild the template arguments using `TransformTemplateArgument()`, which did not guarantee the establishment of PackExpansions as `getInjectedTemplateArguments()` does. This patch fixes that by making it call `RebuildPackExpansion()` if the transformed arguments are still having unexpanded parameter packs. No release note as I think this is a good candidate for backporting. Fixes #<!-- -->124715 --- Full diff: https://github.com/llvm/llvm-project/pull/126206.diff 2 Files Affected: - (modified) clang/lib/Sema/SemaTemplateInstantiate.cpp (+7-1) - (modified) clang/test/AST/ast-dump-ctad-alias.cpp (+44) ``````````diff diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp index 12e98a33d07853e..522bd418e2f1881 100644 --- a/clang/lib/Sema/SemaTemplateInstantiate.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp @@ -1627,8 +1627,14 @@ namespace { TemplateArgumentLoc Input = SemaRef.getTrivialTemplateArgumentLoc( pack, QualType(), SourceLocation{}); TemplateArgumentLoc Output; - if (SemaRef.SubstTemplateArgument(Input, TemplateArgs, Output)) + if (TransformTemplateArgument(Input, Output, Uneval)) return true; // fails + if (Output.getArgument().containsUnexpandedParameterPack()) + // FIXME: Is EllipsisLoc necessary? This pack expansion merely + // serves as a placeholder type for future rewrite-substitution + // (e.g. into constraint expressions.) + Output = + RebuildPackExpansion(Output, SourceLocation{}, std::nullopt); TArgs.push_back(Output.getArgument()); } Output = SemaRef.getTrivialTemplateArgumentLoc( diff --git a/clang/test/AST/ast-dump-ctad-alias.cpp b/clang/test/AST/ast-dump-ctad-alias.cpp index b1631f7822ce017..464808af784c2c3 100644 --- a/clang/test/AST/ast-dump-ctad-alias.cpp +++ b/clang/test/AST/ast-dump-ctad-alias.cpp @@ -156,3 +156,47 @@ ATemplatedClass2 test2(list); // CHECK-NEXT: |-TypeTraitExpr {{.*}} 'bool' __is_deducible } // namespace GH90209 + +namespace GH124715 { + +template <class T, class... Args> +concept invocable = true; + +template <class T, class... Args> struct Struct { + template <class U> + requires invocable<U, Args...> + Struct(U, Args...) {} +}; + +template <class Lambda, class... Args> +Struct(Lambda lambda, Args... args) -> Struct<Lambda, Args...>; + +template <class T, class... Ts> using Alias = Struct<T, Ts...>; + +void foo() { + Alias([](int) {}, 0); +} + +// CHECK: |-FunctionTemplateDecl {{.*}} implicit <deduction guide for Alias> +// CHECK-NEXT: | |-TemplateTypeParmDecl {{.*}} class depth 0 index 0 T +// CHECK-NEXT: | |-TemplateTypeParmDecl {{.*}} class depth 0 index 1 ... Ts +// CHECK-NEXT: | |-TemplateTypeParmDecl {{.*}} class depth 0 index 2 U +// CHECK-NEXT: | |-BinaryOperator {{.*}} 'bool' '&&' +// CHECK-NEXT: | | |-ConceptSpecializationExpr {{.*}} 'bool' Concept {{.*}} 'invocable' +// CHECK-NEXT: | | | |-ImplicitConceptSpecializationDecl {{.*}} +// CHECK-NEXT: | | | | |-TemplateArgument type 'type-parameter-0-2' +// CHECK-NEXT: | | | | | `-TemplateTypeParmType {{.*}} 'type-parameter-0-2' dependent depth 0 index 2 +// CHECK-NEXT: | | | | `-TemplateArgument pack '<type-parameter-0-1...>' +// CHECK-NEXT: | | | | `-TemplateArgument type 'type-parameter-0-1...' +// CHECK-NEXT: | | | | `-PackExpansionType {{.*}} 'type-parameter-0-1...' dependent +// CHECK-NEXT: | | | | `-TemplateTypeParmType {{.*}} 'type-parameter-0-1' dependent contains_unexpanded_pack depth 0 index 1 pack +// CHECK-NEXT: | | | |-TemplateArgument {{.*}} type 'U':'type-parameter-0-2' +// CHECK-NEXT: | | | | `-TemplateTypeParmType {{.*}} 'U' dependent depth 0 index 2 +// CHECK-NEXT: | | | | `-TemplateTypeParm {{.*}} 'U' +// CHECK-NEXT: | | | `-TemplateArgument {{.*}} type 'Ts...':'type-parameter-0-1...' +// CHECK-NEXT: | | | `-PackExpansionType {{.*}} 'Ts...' dependent +// CHECK-NEXT: | | | `-TemplateTypeParmType {{.*}} 'Ts' dependent contains_unexpanded_pack depth 0 index 1 pack +// CHECK-NEXT: | | | `-TemplateTypeParm {{.*}} 'Ts' +// CHECK-NEXT: | | `-TypeTraitExpr {{.*}} 'bool' __is_deducible + +} // namespace GH124715 `````````` </details> https://github.com/llvm/llvm-project/pull/126206 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
