Use class_args field in opclass_drop

This makes it consistent with the usage in opclass_item.
Reviewed-by: Jim Nasby <Jim.Nasby@BlueTreble.com>
Reviewed-by: Michael Paquier <michael.paquier@gmail.com>

src/backend/commands/opclasscmds.c

@@ -989,7 +989,7 @@ AlterOpFamilyDrop(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
 							 errmsg("invalid operator number %d,"
 									" must be between 1 and %d",
 									item->number, maxOpNumber)));
-				processTypesSpec(item->args, &lefttype, &righttype);
+				processTypesSpec(item->class_args, &lefttype, &righttype);
 				/* Save the info */
 				member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
 				member->number = item->number;
@@ -1004,7 +1004,7 @@ AlterOpFamilyDrop(AlterOpFamilyStmt *stmt, Oid amoid, Oid opfamilyoid,
 							 errmsg("invalid procedure number %d,"
 									" must be between 1 and %d",
 									item->number, maxProcNumber)));
-				processTypesSpec(item->args, &lefttype, &righttype);
+				processTypesSpec(item->class_args, &lefttype, &righttype);
 				/* Save the info */
 				member = (OpFamilyMember *) palloc0(sizeof(OpFamilyMember));
 				member->number = item->number;

src/backend/parser/gram.y

@@ -5910,7 +5910,7 @@ opclass_drop:
 					CreateOpClassItem *n = makeNode(CreateOpClassItem);
 					n->itemtype = OPCLASS_ITEM_OPERATOR;
 					n->number = $2;
-					n->args = $4;
+					n->class_args = $4;
 					$$ = (Node *) n;
 				}
 			| FUNCTION Iconst '(' type_list ')'
@@ -5918,7 +5918,7 @@ opclass_drop:
 					CreateOpClassItem *n = makeNode(CreateOpClassItem);
 					n->itemtype = OPCLASS_ITEM_FUNCTION;
 					n->number = $2;
-					n->args = $4;
+					n->class_args = $4;
 					$$ = (Node *) n;
 				}
 		;

src/include/nodes/parsenodes.h

@@ -2424,7 +2424,8 @@ typedef struct CreateOpClassItem
 	List	   *args;			/* argument types */
 	int			number;			/* strategy num or support proc num */
 	List	   *order_family;	/* only used for ordering operators */
-	List	   *class_args;		/* only used for functions */
+	List	   *class_args;		/* amproclefttype/amprocrighttype or
+								 * amoplefttype/amoprighttype */
 	/* fields used for a storagetype item: */
 	TypeName   *storedtype;		/* datatype stored in index */
 } CreateOpClassItem;