Arrange for function default arguments to be processed properly in expressions

that are set up for execution with ExecPrepareExpr rather than going through
the full planner process.  By introducing an explicit notion of "expression
planning", this patch also lays a bit of groundwork for maybe someday
allowing sub-selects in standalone expressions.

src/backend/commands/typecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.129 2009/01/01 17:23:40 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/typecmds.c,v 1.130 2009/01/09 15:46:10 tgl Exp $
  *
  * DESCRIPTION
  *	  The "DefineFoo" routines take the parse tree and pick out the
@@ -50,7 +50,7 @@
 #include "executor/executor.h"
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
-#include "optimizer/planmain.h"
+#include "optimizer/planner.h"
 #include "optimizer/var.h"
 #include "parser/parse_coerce.h"
 #include "parser/parse_expr.h"
@@ -2390,8 +2390,8 @@ GetDomainConstraints(Oid typeOid)
 
 			check_expr = (Expr *) stringToNode(TextDatumGetCString(val));
 
-			/* ExecInitExpr assumes we already fixed opfuncids */
-			fix_opfuncids((Node *) check_expr);
+			/* ExecInitExpr assumes we've planned the expression */
+			check_expr = expression_planner(check_expr);
 
 			r = makeNode(DomainConstraintState);
 			r->constrainttype = DOM_CONSTRAINT_CHECK;