https://github.com/HighCommander4 created https://github.com/llvm/llvm-project/pull/132465
Fixes https://github.com/clangd/clangd/discussions/1056 >From 2855815b91dd924aa56e98ef00f228fdeac9d81d Mon Sep 17 00:00:00 2001 From: Nathan Ridge <zeratul...@hotmail.com> Date: Thu, 13 Mar 2025 01:23:03 -0400 Subject: [PATCH] [clang][HeuristicResolver] Default argument heuristic for template parameters --- clang/lib/Sema/HeuristicResolver.cpp | 15 ++++++++ .../unittests/Sema/HeuristicResolverTest.cpp | 34 +++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/clang/lib/Sema/HeuristicResolver.cpp b/clang/lib/Sema/HeuristicResolver.cpp index 7aecd2a73b539..4544d75ea73c4 100644 --- a/clang/lib/Sema/HeuristicResolver.cpp +++ b/clang/lib/Sema/HeuristicResolver.cpp @@ -11,6 +11,7 @@ #include "clang/AST/CXXInheritance.h" #include "clang/AST/DeclTemplate.h" #include "clang/AST/ExprCXX.h" +#include "clang/AST/TemplateBase.h" #include "clang/AST/Type.h" namespace clang { @@ -247,6 +248,20 @@ QualType HeuristicResolverImpl::simplifyType(QualType Type, const Expr *E, } } } + if (const auto *TTPT = dyn_cast_if_present<TemplateTypeParmType>(T.Type)) { + // We can't do much useful with a template parameter (e.g. we cannot look + // up member names inside it). However, if the template parameter has a + // default argument, as a heuristic we can replace T with the default + // argument type. + if (const auto *TTPD = TTPT->getDecl()) { + if (TTPD->hasDefaultArgument()) { + const auto &DefaultArg = TTPD->getDefaultArgument().getArgument(); + if (DefaultArg.getKind() == TemplateArgument::Type) { + return {DefaultArg.getAsType()}; + } + } + } + } return T; }; // As an additional protection against infinite loops, bound the number of diff --git a/clang/unittests/Sema/HeuristicResolverTest.cpp b/clang/unittests/Sema/HeuristicResolverTest.cpp index c7cfe7917c532..f7eb4b23c2ab0 100644 --- a/clang/unittests/Sema/HeuristicResolverTest.cpp +++ b/clang/unittests/Sema/HeuristicResolverTest.cpp @@ -410,6 +410,40 @@ TEST(HeuristicResolver, MemberExpr_HangIssue126536) { cxxDependentScopeMemberExpr(hasMemberName("foo")).bind("input")); } +TEST(HeuristicResolver, MemberExpr_DefaultTemplateArgument) { + std::string Code = R"cpp( + struct Default { + void foo(); + }; + template <typename T = Default> + void bar(T t) { + t.foo(); + } + )cpp"; + // Test resolution of "foo" in "t.foo()". + expectResolution( + Code, &HeuristicResolver::resolveMemberExpr, + cxxDependentScopeMemberExpr(hasMemberName("foo")).bind("input"), + cxxMethodDecl(hasName("foo")).bind("output")); +} + +TEST(HeuristicResolver, MemberExpr_DefaultTemplateArgument_Recursive) { + std::string Code = R"cpp( + struct Default { + void foo(); + }; + template <typename D = Default, typename T = D> + void bar(T t) { + t.foo(); + } + )cpp"; + // Test resolution of "foo" in "t.foo()". + expectResolution( + Code, &HeuristicResolver::resolveMemberExpr, + cxxDependentScopeMemberExpr(hasMemberName("foo")).bind("input"), + cxxMethodDecl(hasName("foo")).bind("output")); +} + TEST(HeuristicResolver, DeclRefExpr_StaticMethod) { std::string Code = R"cpp( template <typename T> _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
