Split CollateClause into separate raw and analyzed node types.

CollateClause is now used only in raw grammar output, and CollateExpr after
parse analysis.  This is for clarity and to avoid carrying collation names
in post-analysis parse trees: that's both wasteful and possibly misleading,
since the collation's name could be changed while the parsetree still
exists.

Also, clean up assorted infelicities and omissions in processing of the
node type.

6 files changed, 23 insertions, 19 deletions

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 373d2adc71c..1633499f939 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -1993,8 +1993,7 @@ opt_collate_clause:
 				{
 					CollateClause *n = makeNode(CollateClause);
 					n->arg = NULL;
-					n->collnames = $2;
-					n->collOid = InvalidOid;
+					n->collname = $2;
 					n->location = @1;
 					$$ = (Node *) n;
 				}
@@ -2537,8 +2536,7 @@ ColConstraint:
 					 */
 					CollateClause *n = makeNode(CollateClause);
 					n->arg = NULL;
-					n->collnames = $2;
-					n->collOid = InvalidOid;
+					n->collname = $2;
 					n->location = @1;
 					$$ = (Node *) n;
 				}
@@ -9690,8 +9688,8 @@ a_expr:		c_expr									{ $$ = $1; }
 			| a_expr COLLATE any_name
 				{
 					CollateClause *n = makeNode(CollateClause);
-					n->arg = (Expr *) $1;
-					n->collnames = $3;
+					n->arg = $1;
+					n->collname = $3;
 					n->location = @2;
 					$$ = (Node *) n;
 				}
diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index 2fd808d26b2..6aff34dd90d 100644
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -279,11 +279,17 @@ coerce_type(ParseState *pstate, Node *node,
 		if (result)
 			return result;
 	}
-	if (IsA(node, CollateClause))
+	if (IsA(node, CollateExpr))
 	{
-		CollateClause *cc = (CollateClause *) node;
+		/*
+		 * XXX very ugly kluge to push the coercion underneath the CollateExpr.
+		 * This needs to be rethought, as it almost certainly doesn't cover
+		 * all cases.
+		 */
+		CollateExpr *cc = (CollateExpr *) node;
 
-		cc->arg = (Expr *) coerce_type(pstate, (Node *) cc->arg, inputTypeId, targetTypeId, targetTypeMod,
+		cc->arg = (Expr *) coerce_type(pstate, (Node *) cc->arg,
+									   inputTypeId, targetTypeId, targetTypeMod,
 									   ccontext, cformat, location);
 		return (Node *) cc;
 	}
@@ -2121,7 +2127,7 @@ select_common_collation(ParseState *pstate, List *exprs, bool none_ok)
 	{
 		Node	   *pexpr = (Node *) lfirst(lc);
 		Oid			pcoll = exprCollation(pexpr);
-		bool		pexplicit = IsA(pexpr, CollateClause);
+		bool		pexplicit = IsA(pexpr, CollateExpr);
 
 		if (pcoll && pexplicit)
 		{
@@ -2130,7 +2136,7 @@ select_common_collation(ParseState *pstate, List *exprs, bool none_ok)
 			{
 				Node	   *nexpr = (Node *) lfirst(lc2);
 				Oid			ncoll = exprCollation(nexpr);
-				bool		nexplicit = IsA(nexpr, CollateClause);
+				bool		nexplicit = IsA(nexpr, CollateExpr);
 
 				if (!ncoll || !nexplicit)
 					continue;
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 7a4f8cc2497..17bd2bf50ae 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -318,6 +318,7 @@ transformExpr(ParseState *pstate, Node *expr)
 		case T_CoerceViaIO:
 		case T_ArrayCoerceExpr:
 		case T_ConvertRowtypeExpr:
+		case T_CollateExpr:
 		case T_CaseTestExpr:
 		case T_ArrayExpr:
 		case T_CoerceToDomain:
@@ -2103,11 +2104,11 @@ transformTypeCast(ParseState *pstate, TypeCast *tc)
 static Node *
 transformCollateClause(ParseState *pstate, CollateClause *c)
 {
-	CollateClause *newc;
+	CollateExpr *newc;
 	Oid		argtype;
 
-	newc = makeNode(CollateClause);
-	newc->arg = (Expr *) transformExpr(pstate, (Node *) c->arg);
+	newc = makeNode(CollateExpr);
+	newc->arg = (Expr *) transformExpr(pstate, c->arg);
 
 	argtype = exprType((Node *) newc->arg);
 	/*
@@ -2121,8 +2122,7 @@ transformCollateClause(ParseState *pstate, CollateClause *c)
 						format_type_be(argtype)),
 				 parser_errposition(pstate, c->location)));
 
-	newc->collOid = LookupCollation(pstate, c->collnames, c->location);
-	newc->collnames = c->collnames;
+	newc->collOid = LookupCollation(pstate, c->collname, c->location);
 	newc->location = c->location;
 
 	return (Node *) newc;
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index c0eaea71a66..fd1529fb3f9 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -1583,7 +1583,7 @@ FigureColnameInternal(Node *node, char **name)
 			}
 			break;
 		case T_CollateClause:
-			return FigureColnameInternal((Node *) ((CollateClause *) node)->arg, name);
+			return FigureColnameInternal(((CollateClause *) node)->arg, name);
 		case T_CaseExpr:
 			strength = FigureColnameInternal((Node *) ((CaseExpr *) node)->defresult,
 											 name);
diff --git a/src/backend/parser/parse_type.c b/src/backend/parser/parse_type.c
index 2ba9bf51816..f413593f602 100644
--- a/src/backend/parser/parse_type.c
+++ b/src/backend/parser/parse_type.c
@@ -471,7 +471,7 @@ GetColumnDefCollation(ParseState *pstate, ColumnDef *coldef, Oid typeOid)
 	{
 		/* We have a raw COLLATE clause, so look up the collation */
 		location = coldef->collClause->location;
-		result = LookupCollation(pstate, coldef->collClause->collnames,
+		result = LookupCollation(pstate, coldef->collClause->collname,
 								 location);
 	}
 	else if (OidIsValid(coldef->collOid))
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index e876853af02..06baf89886a 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -2467,7 +2467,7 @@ transformColumnType(CreateStmtContext *cxt, ColumnDef *column)
 		Oid		collOid;
 
 		collOid = LookupCollation(cxt->pstate,
-								  column->collClause->collnames,
+								  column->collClause->collname,
 								  column->collClause->location);
 		/* Complain if COLLATE is applied to an uncollatable type */
 		if (!OidIsValid(typtup->typcollation))