[Sema] Avoid using a null type pointer (fixes PR32750)

isMicrosoftMissingTypename() uses a Type pointer without first checking
that it's non-null. PR32750 reports a case where the pointer is in fact
null. This patch adds in a defensive check and a regression test.

Differential Revision: https://reviews.llvm.org/D32519

llvm-svn: 301420

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index e7ea68e..f838c9a 100644 (file)
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -615,7 +615,7 @@ bool Sema::isMicrosoftMissingTypename(const CXXScopeSpec *SS, Scope *S) {
 
     CXXRecordDecl *RD = cast<CXXRecordDecl>(CurContext);
     for (const auto &Base : RD->bases())
-      if (Context.hasSameUnqualifiedType(QualType(Ty, 1), Base.getType()))
+      if (Ty && Context.hasSameUnqualifiedType(QualType(Ty, 1), Base.getType()))
         return true;
     return S->isFunctionPrototypeScope();
   }

diff --git a/clang/test/SemaCXX/MicrosoftExtensions.cpp b/clang/test/SemaCXX/MicrosoftExtensions.cpp
index 96088a0..38949e1 100644 (file)
--- a/clang/test/SemaCXX/MicrosoftExtensions.cpp
+++ b/clang/test/SemaCXX/MicrosoftExtensions.cpp
@@ -2,6 +2,7 @@
 // RUN: %clang_cc1 -std=c++98 %s -triple i686-pc-win32 -fsyntax-only -Wmicrosoft -Wc++11-extensions -Wno-long-long -verify -fms-extensions -fexceptions -fcxx-exceptions -DTEST1
 // RUN: %clang_cc1 -std=c++11 %s -triple i686-pc-win32 -fsyntax-only -Wmicrosoft -Wc++11-extensions -Wno-long-long -verify -fms-extensions -fexceptions -fcxx-exceptions -DTEST1
 // RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -Wmicrosoft -Wc++11-extensions -Wno-long-long -verify -fexceptions -fcxx-exceptions -DTEST2
+// RUN: %clang_cc1 %s -triple i686-pc-win32 -fsyntax-only -std=c++11 -fms-compatibility -verify -DTEST3
 
 #if TEST1
 
@@ -508,6 +509,13 @@ int S::fn() { return 0; } // expected-warning {{is missing exception specificati
 // Check that __unaligned is not recognized if MS extensions are not enabled
 typedef char __unaligned *aligned_type; // expected-error {{expected ';' after top level declarator}}
 
+#elif TEST3
+
+namespace PR32750 {
+template<typename T> struct A {};
+template<typename T> struct B : A<A<T>> { A<T>::C::D d; }; // expected-error {{missing 'typename' prior to dependent type name 'A<T>::C::D'}}
+}
+
 #else
 
 #error Unknown test mode