Add an assertion to make our intention more clear.

llvm-svn: 58030
diff --git a/clang/lib/Analysis/GRExprEngine.cpp b/clang/lib/Analysis/GRExprEngine.cpp
index 4d771fb..cbda7be 100644
--- a/clang/lib/Analysis/GRExprEngine.cpp
+++ b/clang/lib/Analysis/GRExprEngine.cpp
@@ -1506,6 +1506,8 @@
 
     // StoreManager casts array to different values.
     if (ExTy->isArrayType()) {
+      assert(T->isPointerType());
+
       V = StateMgr.ArrayToPointer(V);
       MakeNode(Dst, CastE, N, SetSVal(St, CastE, V));
       continue;