r322438 - [Sema] Fix crash for type-dependent base classes

[Jan Korous via cfe-commits]

Author: jkorous
Date: Sat Jan 13 07:24:16 2018
New Revision: 322438

URL: http://llvm.org/viewvc/llvm-project?rev=322438&view=rev
Log:
[Sema] Fix crash for type-dependent base classes

Added:
    cfe/trunk/test/SemaCXX/base-class-ambiguity-check.cpp
Modified:
    cfe/trunk/lib/Sema/SemaDeclCXX.cpp

Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=322438&r1=322437&r2=322438&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Sat Jan 13 07:24:16 2018
@@ -2417,9 +2417,16 @@ bool Sema::AttachBaseSpecifiers(CXXRecor
   // Attach the remaining base class specifiers to the derived class.
   Class->setBases(Bases.data(), NumGoodBases);
 
+  // Check that the only base classes that are duplicate are virtual.
   for (unsigned idx = 0; idx < NumGoodBases; ++idx) {
     // Check whether this direct base is inaccessible due to ambiguity.
     QualType BaseType = Bases[idx]->getType();
+
+    // Skip all dependent types in templates being used as base specifiers.
+    // Checks below assume that the base specifier is a CXXRecord.
+    if (BaseType->isDependentType())
+      continue;
+
     CanQualType CanonicalBase = Context.getCanonicalType(BaseType)
       .getUnqualifiedType();
 

Added: cfe/trunk/test/SemaCXX/base-class-ambiguity-check.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/base-class-ambiguity-check.cpp?rev=322438&view=auto
==============================================================================
--- cfe/trunk/test/SemaCXX/base-class-ambiguity-check.cpp (added)
+++ cfe/trunk/test/SemaCXX/base-class-ambiguity-check.cpp Sat Jan 13 07:24:16 2018
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+template <typename T> class Foo {
+  struct Base : T {};
+
+  // Test that this code no longer causes a crash in Sema. rdar://23291875
+  struct Derived : Base, T {};
+};