Author: Yupei Liu Date: 2024-07-09T16:39:50+08:00 New Revision: f0c7505f597998c84023ccd609ecfc9af3d5b4d6
URL: https://github.com/llvm/llvm-project/commit/f0c7505f597998c84023ccd609ecfc9af3d5b4d6 DIFF: https://github.com/llvm/llvm-project/commit/f0c7505f597998c84023ccd609ecfc9af3d5b4d6.diff LOG: [Clang] Fix the order of addInstantiatedParameters in LambdaScopeForCallOperatorInstantiationRAII (#97215) Currently, `addInstantiatedParameters` is called from the innermost lambda outward. However, when the function parameters of an inner lambda depend on the function parameters of an outer lambda, it can lead to a crash due to the inability to find a mapping for the instantiated decl. This PR corrects this behavior by calling `addInstantiatedParameters` from the outside in. repro code: https://godbolt.org/z/KbsxWesW6 ```cpp namespace dependent_param_concept { template <typename... Ts> void sink(Ts...) {} void dependent_param() { auto L = [](auto... x) { return [](decltype(x)... y) { // `y` depends on `x` return [](int z) requires requires { sink(y..., z); } {}; }; }; L(0, 1)(1, 2)(1); } } // namespace dependent_param_concept ``` This PR is a prerequisite for implmenting #61426 Added: Modified: clang/docs/ReleaseNotes.rst clang/lib/Sema/SemaLambda.cpp clang/test/SemaTemplate/concepts-lambda.cpp Removed: ################################################################################ diff --git a/clang/docs/ReleaseNotes.rst b/clang/docs/ReleaseNotes.rst index 795712eac1052..e3ed18e1b288a 100644 --- a/clang/docs/ReleaseNotes.rst +++ b/clang/docs/ReleaseNotes.rst @@ -962,6 +962,7 @@ Bug Fixes to C++ Support - Fix a crash caused by improper use of ``__array_extent``. (#GH80474) - Fixed several bugs in capturing variables within unevaluated contexts. (#GH63845), (#GH67260), (#GH69307), (#GH88081), (#GH89496), (#GH90669) and (#GH91633). +- Fixed a crash in constraint instantiation under nested lambdas with dependent parameters. - Fixed handling of brace ellison when building deduction guides. (#GH64625), (#GH83368). - Clang now instantiates local constexpr functions eagerly for constant evaluators. (#GH35052), (#GH94849) - Fixed a failed assertion when attempting to convert an integer representing the diff erence diff --git a/clang/lib/Sema/SemaLambda.cpp b/clang/lib/Sema/SemaLambda.cpp index 56818042952a6..4b19296e8a23a 100644 --- a/clang/lib/Sema/SemaLambda.cpp +++ b/clang/lib/Sema/SemaLambda.cpp @@ -2383,23 +2383,37 @@ Sema::LambdaScopeForCallOperatorInstantiationRAII:: SemaRef.RebuildLambdaScopeInfo(cast<CXXMethodDecl>(FD)); - FunctionDecl *Pattern = getPatternFunctionDecl(FD); - if (Pattern) { - SemaRef.addInstantiatedCapturesToScope(FD, Pattern, Scope, MLTAL); + FunctionDecl *FDPattern = getPatternFunctionDecl(FD); + if (!FDPattern) + return; - FunctionDecl *ParentFD = FD; - while (ShouldAddDeclsFromParentScope) { + SemaRef.addInstantiatedCapturesToScope(FD, FDPattern, Scope, MLTAL); - ParentFD = - dyn_cast<FunctionDecl>(getLambdaAwareParentOfDeclContext(ParentFD)); - Pattern = - dyn_cast<FunctionDecl>(getLambdaAwareParentOfDeclContext(Pattern)); + if (!ShouldAddDeclsFromParentScope) + return; - if (!ParentFD || !Pattern) - break; + llvm::SmallVector<std::pair<FunctionDecl *, FunctionDecl *>, 4> + ParentInstantiations; + while (true) { + FDPattern = + dyn_cast<FunctionDecl>(getLambdaAwareParentOfDeclContext(FDPattern)); + FD = dyn_cast<FunctionDecl>(getLambdaAwareParentOfDeclContext(FD)); - SemaRef.addInstantiatedParametersToScope(ParentFD, Pattern, Scope, MLTAL); - SemaRef.addInstantiatedLocalVarsToScope(ParentFD, Pattern, Scope); - } + if (!FDPattern || !FD) + break; + + ParentInstantiations.emplace_back(FDPattern, FD); + } + + // Add instantiated parameters and local vars to scopes, starting from the + // outermost lambda to the innermost lambda. This ordering ensures that + // parameters in inner lambdas can correctly depend on those defined + // in outer lambdas, e.g. auto L = [](auto... x) { + // return [](decltype(x)... y) { }; // `y` depends on `x` + // }; + + for (const auto &[FDPattern, FD] : llvm::reverse(ParentInstantiations)) { + SemaRef.addInstantiatedParametersToScope(FD, FDPattern, Scope, MLTAL); + SemaRef.addInstantiatedLocalVarsToScope(FD, FDPattern, Scope); } } diff --git a/clang/test/SemaTemplate/concepts-lambda.cpp b/clang/test/SemaTemplate/concepts-lambda.cpp index 280be71284f97..252ef08549a48 100644 --- a/clang/test/SemaTemplate/concepts-lambda.cpp +++ b/clang/test/SemaTemplate/concepts-lambda.cpp @@ -237,3 +237,17 @@ concept D = []<C T = int>() { return true; }(); D auto x = 0; } // namespace GH93821 + +namespace dependent_param_concept { +template <typename... Ts> void sink(Ts...) {} +void dependent_param() { + auto L = [](auto... x) { + return [](decltype(x)... y) { + return [](int z) + requires requires { sink(y..., z); } + {}; + }; + }; + L(0, 1)(1, 2)(1); +} +} // namespace dependent_param_concept _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
