Fix/test decltype dtor calls with invalid base expression.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146354 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Sema/SemaExprCXX.cpp

@@ -266,7 +266,7 @@ ParsedType Sema::getDestructorName(SourceLocation TildeLoc,
 }
 
 ParsedType Sema::getDestructorType(const DeclSpec& DS, ParsedType ObjectType) {
-    if (DS.getTypeSpecType() == DeclSpec::TST_error)
+    if (DS.getTypeSpecType() == DeclSpec::TST_error || !ObjectType)
       return ParsedType();
     assert(DS.getTypeSpecType() == DeclSpec::TST_decltype 
            && "only get destructor types from declspecs");

test/CXX/special/class.dtor/p10-0x.cpp

@@ -22,4 +22,5 @@ void a(const A *x) {
   x->~decltype(x)(); // expected-error{{destructor type 'decltype(x)' (aka 'const A *') in object destruction expression does not match the type 'const A' of the object being destroyed}}
   // this last one could be better, mentioning that the nested-name-specifier could be removed or a type name after the ~
   x->::A::~decltype(*x)(); // expected-error{{expected a class name after '~' to name a destructor}}
+  y->~decltype(A())(); // expected-error{{use of undeclared identifier 'y'}}
 }