From bd763e2cf7c1d84bab95064cc5cbe542b227b025 Mon Sep 17 00:00:00 2001 From: Haojian Wu <hokein.wu@gmail.com> Date: Tue, 17 Mar 2020 21:39:19 +0100 Subject: [PATCH] [clang] Fix crash on visiting null nestedNameSpecifier. Summary: Fix https://github.com/clangd/clangd/issues/293 Reviewers: sammccall Subscribers: ilya-biryukov, kadircet, usaxena95, cfe-commits Tags: #clang Differential Revision: https://reviews.llvm.org/D76320 --- clang/lib/Sema/SemaTemplate.cpp | 5 ++++- clang/test/Parser/cxx-template-decl.cpp | 6 ++++++ 2 files changed, 10 insertions(+), 1 deletion(-) diff --git a/clang/lib/Sema/SemaTemplate.cpp b/clang/lib/Sema/SemaTemplate.cpp index 1ba66d4a976a..f95b16c1cbae 100755 --- a/clang/lib/Sema/SemaTemplate.cpp +++ b/clang/lib/Sema/SemaTemplate.cpp @@ -5928,7 +5928,9 @@ bool UnnamedLocalNoLinkageFinder::VisitDependentNameType( bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType( const DependentTemplateSpecializationType* T) { - return VisitNestedNameSpecifier(T->getQualifier()); + if (auto *Q = T->getQualifier()) + return VisitNestedNameSpecifier(Q); + return false; } bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType( @@ -5982,6 +5984,7 @@ bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) { bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier( NestedNameSpecifier *NNS) { + assert(NNS); if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix())) return true; diff --git a/clang/test/Parser/cxx-template-decl.cpp b/clang/test/Parser/cxx-template-decl.cpp index 3d7a3dc14f4c..0d52ad8fb50f 100644 --- a/clang/test/Parser/cxx-template-decl.cpp +++ b/clang/test/Parser/cxx-template-decl.cpp @@ -273,3 +273,9 @@ namespace AnnotateAfterInvalidTemplateId { namespace PR45063 { template<class=class a::template b<>> struct X {}; // expected-error {{undeclared identifier 'a'}} } + +namespace NoCrashOnEmptyNestedNameSpecifier { + template <typename FnT, + typename T = typename ABC<FnT>::template arg_t<0>> // expected-error {{no template named 'ABC'}} + void foo(FnT) {} +}