modocache created this revision. modocache added a reviewer: rsmith. The documentation for RecursiveASTVisitor::TraverseDecl states that the Decl being traversed may be null. In fact, this is the case when a CXXCatchStmt with no exception decl is traversed. Because the visitor for diagnosing unexpanded parameter packs does not check for null, it ends up crashing when it attempts to call the Decl::isParameterPack method on a null Decl pointer.
Add a null check to prevent an ICE, and a test case that would crash otherwise. Also, because the test requires C++ exceptions and C++14, change the test parameters for the entire test file. (Alternatively, I thought about adding a new test file, but went with this approach for my own convenience.) Co-authored-by: Andreas Molzer <andreas.mol...@gmx.de> Co-authored-by: Mara Bos <m-ou...@m-ou.se> Repository: rC Clang https://reviews.llvm.org/D56271 Files: lib/Sema/SemaTemplateVariadic.cpp test/SemaCXX/alias-template.cpp Index: test/SemaCXX/alias-template.cpp =================================================================== --- test/SemaCXX/alias-template.cpp +++ test/SemaCXX/alias-template.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 -verify -std=c++11 %s +// RUN: %clang_cc1 -verify -std=c++14 -fcxx-exceptions %s namespace RedeclAliasTypedef { template<typename U> using T = int; @@ -189,3 +189,7 @@ int g = sfinae_me<int>(); // expected-error{{no matching function for call to 'sfinae_me'}} } + +namespace NullExceptionDecl { +template<int... I> auto get = []() { try { } catch(...) {}; return I; }; // expected-error{{initializer contains unexpanded parameter pack 'I'}} +} Index: lib/Sema/SemaTemplateVariadic.cpp =================================================================== --- lib/Sema/SemaTemplateVariadic.cpp +++ lib/Sema/SemaTemplateVariadic.cpp @@ -164,7 +164,7 @@ // A function parameter pack is a pack expansion, so cannot contain // an unexpanded parameter pack. Likewise for a template parameter // pack that contains any references to other packs. - if (D->isParameterPack()) + if (D && D->isParameterPack()) return true; return inherited::TraverseDecl(D);
Index: test/SemaCXX/alias-template.cpp =================================================================== --- test/SemaCXX/alias-template.cpp +++ test/SemaCXX/alias-template.cpp @@ -1,4 +1,4 @@ -// RUN: %clang_cc1 -verify -std=c++11 %s +// RUN: %clang_cc1 -verify -std=c++14 -fcxx-exceptions %s namespace RedeclAliasTypedef { template<typename U> using T = int; @@ -189,3 +189,7 @@ int g = sfinae_me<int>(); // expected-error{{no matching function for call to 'sfinae_me'}} } + +namespace NullExceptionDecl { +template<int... I> auto get = []() { try { } catch(...) {}; return I; }; // expected-error{{initializer contains unexpanded parameter pack 'I'}} +} Index: lib/Sema/SemaTemplateVariadic.cpp =================================================================== --- lib/Sema/SemaTemplateVariadic.cpp +++ lib/Sema/SemaTemplateVariadic.cpp @@ -164,7 +164,7 @@ // A function parameter pack is a pack expansion, so cannot contain // an unexpanded parameter pack. Likewise for a template parameter // pack that contains any references to other packs. - if (D->isParameterPack()) + if (D && D->isParameterPack()) return true; return inherited::TraverseDecl(D);
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