[AST] Fix a crash on a dependent vector_size attribute

[erik.pilkington]

Summary

Looks like this was just a copy & paste mistake from getDependentSizedExtVectorType.

rdar://60092165

[aaron.ballman]

LGTM!

clang/lib/AST/ASTContext.cpp

if (CanonVecTy == VecType) {
 
       DependentVectorType *CanonCheck =
           DependentVectorTypes.FindNodeOrInsertPos(ID, InsertPos);
       assert(!CanonCheck &&
              "Dependent-sized vector_size canonical type broken");
       (void)CanonCheck;
       DependentVectorTypes.InsertNode(New, InsertPos);
     } else {
-      QualType CanonExtTy = getDependentSizedExtVectorType(CanonVecTy, SizeExpr,
-                                                           SourceLocation());
+      QualType CanonTy = getDependentVectorType(CanonVecTy, SizeExpr,
+                                                SourceLocation(), VecKind);
       New = new (*this, TypeAlignment) DependentVectorType(
-          *this, VecType, CanonExtTy, SizeExpr, AttrLoc, VecKind);
+          *this, VecType, CanonTy, SizeExpr, AttrLoc, VecKind);
     }
   }
 
   Types.push_back(New);
   return QualType(New, 0);
 }
 
 /// getExtVectorType - Return the unique reference to an extended vector type of

clang/test/SemaCXX/vector.cpp

#if __cplusplus >= 201103L
   // expected-note@+1{{in instantiation of member function}}
   DiagTrunc<double>().f(theFloat4);
   // expected-note@+1{{in instantiation of member function}}
   DiagTruncDependentType<double>().f(theFloat4);
   PR45298Consumer<double>().f(theFloat4);
 #endif // __cplusplus >= 201103L
 }
 }
+
+namespace rdar60092165 {
+template <class T> void f() {
+  typedef T first_type __attribute__((vector_size(sizeof(T) * 4)));
+  typedef T second_type __attribute__((vector_size(sizeof(T) * 4)));
+
+  second_type st;
+}
+}