Author: 刘雨培 Date: 2024-01-05T01:32:10+08:00 New Revision: e78a1f491cbc0a57de7bf86058359dd0bd282540
URL: https://github.com/llvm/llvm-project/commit/e78a1f491cbc0a57de7bf86058359dd0bd282540 DIFF: https://github.com/llvm/llvm-project/commit/e78a1f491cbc0a57de7bf86058359dd0bd282540.diff LOG: [Clang] Fix the instantiation of return type requirements in lambda bodies (#76967) Currently, due to the incomplete implementation of p0588r1, the instantiation of lambda expressions leads to the instantiation of the body. And `EvaluateConstraints` is false during the instantiation of the body, which causes crashes during the instantiation of the return type requirement: ```cpp template<typename T> concept doesnt_matter = true; template<class T> concept test = []{ return requires(T t) { { t } -> doesnt_matter; // crash }; }(); static_assert(test<int>); ``` Although a complete implementation of p0588r1 can solve these crashes, it will take some time. Therefore, this pull request aims to fix these crashes first. Fixes https://github.com/llvm/llvm-project/issues/63808 Fixes https://github.com/llvm/llvm-project/issues/64607 Fixes https://github.com/llvm/llvm-project/issues/64086 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/Sema/SemaTemplateInstantiate.cpp clang/test/SemaTemplate/concepts-lambda.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index c7bf162426a68c..e5de042cebd4c0 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -844,6 +844,11 @@ Bug Fixes to C++ Support - Fix crash when parsing nested requirement. Fixes: (`#73112 <https://github.com/llvm/llvm-project/issues/73112>`_) +- Fixed a crash caused by using return type requirement in a lambda. Fixes: + (`#63808 <https://github.com/llvm/llvm-project/issues/63808>`_) + (`#64607 <https://github.com/llvm/llvm-project/issues/64607>`_) + (`#64086 <https://github.com/llvm/llvm-project/issues/64086>`_) + Bug Fixes to AST Handling ^^^^^^^^^^^^^^^^^^^^^^^^^ - Fixed an import failure of recursive friend class template. diff --git a/clang/lib/Sema/SemaTemplateInstantiate.cpp b/clang/lib/Sema/SemaTemplateInstantiate.cpp index 37e5b9cad08bc9..e1cbdcd72eac1d 100644 --- a/clang/lib/Sema/SemaTemplateInstantiate.cpp +++ b/clang/lib/Sema/SemaTemplateInstantiate.cpp @@ -1479,6 +1479,23 @@ namespace { return Result; } + StmtResult TransformLambdaBody(LambdaExpr *E, Stmt *Body) { + // Currently, we instantiate the body when instantiating the lambda + // expression. However, `EvaluateConstraints` is disabled during the + // instantiation of the lambda expression, causing the instantiation + // failure of the return type requirement in the body. If p0588r1 is fully + // implemented, the body will be lazily instantiated, and this problem + // will not occur. Here, `EvaluateConstraints` is temporarily set to + // `true` to temporarily fix this issue. + // FIXME: This temporary fix can be removed after fully implementing + // p0588r1. + bool Prev = EvaluateConstraints; + EvaluateConstraints = true; + StmtResult Stmt = inherited::TransformLambdaBody(E, Body); + EvaluateConstraints = Prev; + return Stmt; + } + ExprResult TransformRequiresExpr(RequiresExpr *E) { LocalInstantiationScope Scope(SemaRef, /*CombineWithOuterScope=*/true); ExprResult TransReq = inherited::TransformRequiresExpr(E); diff --git a/clang/test/SemaTemplate/concepts-lambda.cpp b/clang/test/SemaTemplate/concepts-lambda.cpp index 8a184cbf4e9bc2..7e431529427dff 100644 --- a/clang/test/SemaTemplate/concepts-lambda.cpp +++ b/clang/test/SemaTemplate/concepts-lambda.cpp @@ -116,3 +116,36 @@ static_assert(E<int>); // expected-note@-11{{because 'Q.template operator()<float>()' would be invalid: no matching member function for call to 'operator()'}} } } + +namespace ReturnTypeRequirementInLambda { +template <typename T> +concept C1 = true; + +template <class T> +concept test = [] { + return requires(T t) { + { t } -> C1; + }; +}(); + +static_assert(test<int>); + +template <typename T> +concept C2 = true; +struct S1 { + int f1() { return 1; } +}; + +void foo() { + auto make_caller = []<auto member> { + return [](S1 *ps) { + if constexpr (requires { + { (ps->*member)() } -> C2; + }) + ; + }; + }; + + auto caller = make_caller.operator()<&S1::f1>(); +} +} // namespace ReturnTypeRequirementInLambda _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
