Index: src/backend/parser/parse_expr.c
===================================================================
--- src/backend/parser/parse_expr.c	(revision 377)
+++ src/backend/parser/parse_expr.c	(working copy)
@@ -2226,11 +2226,11 @@
 	Oid			targetType;
 	int32		targetTypmod;
 
-	targetType = typenameTypeId(pstate, typename, &targetTypmod);
-
 	if (inputType == InvalidOid)
 		return expr;			/* do nothing if NULL input */
 
+	targetType = typenameTypeId(pstate, typename, &targetTypmod);
+
 	expr = coerce_to_target_type(pstate, expr, inputType,
 								 targetType, targetTypmod,
 								 COERCION_EXPLICIT,