When you do "ARRAY[...]::domain", where domain is a domain over an array type,

hlinnaka · hlinnaka · commit 942702a496c3 · 2009-11-13T16:09:10.000Z
we need to check domain constraints. We used to do it correctly, but 8.4
introduced a separate code path for the "ARRAY[]::arraytype" case to infer
the type of an empty ARRAY construct from the cast target, and forgot to take
domains into account.

Per report from Florian G. Pflug.
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.248 2009/11/09 02:36:56 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/parse_expr.c,v 1.249 2009/11/13 16:09:10 heikki Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -169,6 +169,20 @@ transformExpr(ParseState *pstate, Node *expr)
 													targetType,
 													elementType,
 													targetTypmod);
+
+						/*
+						 * If the target array type is a domain, we still need
+						 * to check the domain constraint. (coerce_to_domain
+						 * is a no-op if targetType is not a domain)
+						 */
+						result = coerce_to_domain(result,
+												  InvalidOid,
+												  -1,
+												  targetType,
+												  COERCE_IMPLICIT_CAST,
+												  tc->location,
+												  false,
+												  true);
 						break;
 					}
 
