Switch assert(0/false) llvm_unreachable.

llvm-svn: 140367
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index 274c74c..c75e337 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -1387,7 +1387,7 @@
       else {
         // Can't be a DependentSizedArrayType or an IncompleteArrayType since
         // UnqAT is not incomplete and Range is not type-dependent.
-        assert(0 && "Unexpected array type in for-range");
+        llvm_unreachable("Unexpected array type in for-range");
         return StmtError();
       }