not-a-whatever.patch

diff --git a/src/backend/commands/comment.c b/src/backend/commands/comment.c
index b578818..9701233 100644
--- a/src/backend/commands/comment.c
+++ b/src/backend/commands/comment.c
@@ -22,6 +22,7 @@
 #include "catalog/pg_shdescription.h"
 #include "commands/comment.h"
 #include "commands/dbcommands.h"
+#include "commands/tablecmds.h"
 #include "libpq/be-fsstubs.h"
 #include "miscadmin.h"
 #include "parser/parse_func.h"
@@ -583,10 +584,7 @@ CheckAttributeComment(Relation relation)
 	if (relation->rd_rel->relkind != RELKIND_RELATION &&
 		relation->rd_rel->relkind != RELKIND_VIEW &&
 		relation->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table, view, or composite type",
-						RelationGetRelationName(relation))));
+		ErrorWrongRelationType(relation, "COMMENT ON COLUMN");
 }
 
 /*
diff --git a/src/backend/commands/seclabel.c b/src/backend/commands/seclabel.c
index 762bbae..00b64bf 100644
--- a/src/backend/commands/seclabel.c
+++ b/src/backend/commands/seclabel.c
@@ -366,10 +366,7 @@ CheckAttributeSecLabel(Relation relation)
 	if (relation->rd_rel->relkind != RELKIND_RELATION &&
 		relation->rd_rel->relkind != RELKIND_VIEW &&
 		relation->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table, view, or composite type",
-						RelationGetRelationName(relation))));
+		ErrorWrongRelationType(relation, "SECURITY LABEL ON COLUMN");
 }
 
 void
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 6729d83..ee410c4 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -222,6 +222,44 @@ static const struct dropmsgstrings dropmsgstringarray[] = {
 	{'\0', 0, NULL, NULL, NULL, NULL}
 };
 
+/*
+ * Error-reporting support for wrong-object type errors
+ */
+struct wrongtypestrings
+{
+	char		kind;
+	const char *wrongtype_message;
+};
+
+static const struct wrongtypestrings wrongtypestringarray[] = {
+	{RELKIND_RELATION,
+		/* translator: %s is an SQL command */
+		gettext_noop("tables do not support %s")},
+	{RELKIND_SEQUENCE,
+		/* translator: %s is an SQL command */
+		gettext_noop("sequences do not support %s")},
+	{RELKIND_VIEW,
+		/* translator: %s is an SQL command */
+		gettext_noop("views do not support %s")},
+	{RELKIND_INDEX,
+		/* translator: %s is an SQL command */
+		gettext_noop("indexes do not support %s")},
+	{RELKIND_COMPOSITE_TYPE,
+		/* translator: %s is an SQL command */
+		gettext_noop("composite types do not support %s")},
+	{RELKIND_TOASTVALUE,
+		/* translator: %s is an SQL command */
+		gettext_noop("TOAST tables do not support %s")},
+	{'\0', NULL}
+};
+
+/* Convenience strings for ATSimplePermissions */
+const char rk_relation[2] = { RELKIND_RELATION, '\0' };
+const char rk_view[2] = { RELKIND_VIEW, '\0' };
+const char rk_relation_view[3] = { RELKIND_RELATION, RELKIND_VIEW, '\0' };
+const char rk_relation_index[3] = { RELKIND_RELATION, RELKIND_INDEX, '\0' };
+const char rk_relation_type[3] =
+	{ RELKIND_RELATION, RELKIND_COMPOSITE_TYPE, '\0' };
 
 static void truncate_check_rel(Relation rel);
 static List *MergeAttributes(List *schema, List *supers, char relpersistence,
@@ -264,8 +302,8 @@ static void ATExecCmd(List **wqueue, AlteredTableInfo *tab, Relation rel,
 static void ATRewriteTables(List **wqueue, LOCKMODE lockmode);
 static void ATRewriteTable(AlteredTableInfo *tab, Oid OIDNewHeap, LOCKMODE lockmode);
 static AlteredTableInfo *ATGetQueueEntry(List **wqueue, Relation rel);
-static void ATSimplePermissions(Relation rel, bool allowView, bool allowType);
-static void ATSimplePermissionsRelationOrIndex(Relation rel);
+static void ATSimplePermissions(Relation rel, const char *relkinds,
+					const char *command);
 static void ATSimpleRecursion(List **wqueue, Relation rel,
 				  AlterTableCmd *cmd, bool recurse, LOCKMODE lockmode);
 static void ATOneLevelRecursion(List **wqueue, Relation rel,
@@ -1096,10 +1134,7 @@ truncate_check_rel(Relation rel)
 
 	/* Only allow truncate on regular tables */
 	if (rel->rd_rel->relkind != RELKIND_RELATION)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table",
-						RelationGetRelationName(rel))));
+		ErrorWrongRelationType(rel, "TRUNCATE");
 
 	/* Permissions checks */
 	aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
@@ -1994,8 +2029,7 @@ renameatt_internal(Oid myrelid,
 		relkind != RELKIND_INDEX)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-			   errmsg("\"%s\" is not a table, view, composite type or index",
-					  RelationGetRelationName(targetrelation))));
+				 errmsg("system-generated column names may not be altered")));
 
 	/*
 	 * permissions checking.  only the owner of a class can change its schema.
@@ -2684,14 +2718,14 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 	switch (cmd->subtype)
 	{
 		case AT_AddColumn:		/* ADD COLUMN */
-			ATSimplePermissions(rel, false, true);
+			ATSimplePermissions(rel, rk_relation_type, "ADD COLUMN");
 			/* Performs own recursion */
 			ATPrepAddColumn(wqueue, rel, recurse, recursing, cmd, lockmode);
 			pass = AT_PASS_ADD_COL;
 			break;
 		case AT_AddColumnToView:		/* add column via CREATE OR REPLACE
 										 * VIEW */
-			ATSimplePermissions(rel, true, false);
+			ATSimplePermissions(rel, rk_view, "ADD COLUMN");
 			/* Performs own recursion */
 			ATPrepAddColumn(wqueue, rel, recurse, recursing, cmd, lockmode);
 			pass = AT_PASS_ADD_COL;
@@ -2704,19 +2738,20 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			 * substitutes default values into INSERTs before it expands
 			 * rules.
 			 */
-			ATSimplePermissions(rel, true, false);
+			ATSimplePermissions(rel, rk_relation_view,
+				"ALTER COLUMN DEFAULT");
 			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
 			/* No command-specific prep needed */
 			pass = cmd->def ? AT_PASS_ADD_CONSTR : AT_PASS_DROP;
 			break;
 		case AT_DropNotNull:	/* ALTER COLUMN DROP NOT NULL */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "DROP NOT NULL");
 			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
 			/* No command-specific prep needed */
 			pass = AT_PASS_DROP;
 			break;
 		case AT_SetNotNull:		/* ALTER COLUMN SET NOT NULL */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "SET NOT NULL");
 			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
 			/* No command-specific prep needed */
 			pass = AT_PASS_ADD_CONSTR;
@@ -2728,31 +2763,37 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_MISC;
 			break;
 		case AT_SetOptions:		/* ALTER COLUMN SET ( options ) */
+			/* This command never recurses */
+			ATSimplePermissions(rel, rk_relation_index,
+								"ALTER COLUMN SET (...)");
+			pass = AT_PASS_MISC;
+			break;
 		case AT_ResetOptions:	/* ALTER COLUMN RESET ( options ) */
-			ATSimplePermissionsRelationOrIndex(rel);
 			/* This command never recurses */
+			ATSimplePermissions(rel, rk_relation_index,
+								"ALTER COLUMN RESET (...)");
 			pass = AT_PASS_MISC;
 			break;
 		case AT_SetStorage:		/* ALTER COLUMN SET STORAGE */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "ALTER COLUMN SET STORAGE");
 			ATSimpleRecursion(wqueue, rel, cmd, recurse, lockmode);
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
 			break;
 		case AT_DropColumn:		/* DROP COLUMN */
-			ATSimplePermissions(rel, false, true);
+			ATSimplePermissions(rel, rk_relation_type, "DROP COLUMN");
 			ATPrepDropColumn(wqueue, rel, recurse, recursing, cmd, lockmode);
 			/* Recursion occurs during execution phase */
 			pass = AT_PASS_DROP;
 			break;
 		case AT_AddIndex:		/* ADD INDEX */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "ADD INDEX");
 			/* This command never recurses */
 			/* No command-specific prep needed */
 			pass = AT_PASS_ADD_INDEX;
 			break;
 		case AT_AddConstraint:	/* ADD CONSTRAINT */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "ADD CONSTRAINT");
 			/* Recursion occurs during execution phase */
 			/* No command-specific prep needed except saving recurse flag */
 			if (recurse)
@@ -2760,7 +2801,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_ADD_CONSTR;
 			break;
 		case AT_DropConstraint:	/* DROP CONSTRAINT */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "DROP CONSTRAINT");
 			/* Recursion occurs during execution phase */
 			/* No command-specific prep needed except saving recurse flag */
 			if (recurse)
@@ -2768,7 +2809,7 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_DROP;
 			break;
 		case AT_AlterColumnType:		/* ALTER COLUMN TYPE */
-			ATSimplePermissions(rel, false, true);
+			ATSimplePermissions(rel, rk_relation_type, "ALTER COLUMN TYPE");
 			/* Performs own recursion */
 			ATPrepAlterColumnType(wqueue, tab, rel, recurse, recursing, cmd, lockmode);
 			pass = AT_PASS_ALTER_TYPE;
@@ -2779,21 +2820,26 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_MISC;
 			break;
 		case AT_ClusterOn:		/* CLUSTER ON */
+			ATSimplePermissions(rel, rk_relation, "CLUSTER ON");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_DropCluster:	/* SET WITHOUT CLUSTER */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "SET WITHOUT CLUSTER");
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
 			break;
 		case AT_AddOids:		/* SET WITH OIDS */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "SET WITH OIDS");
 			/* Performs own recursion */
 			if (!rel->rd_rel->relhasoids || recursing)
 				ATPrepAddOids(wqueue, rel, recurse, cmd, lockmode);
 			pass = AT_PASS_ADD_COL;
 			break;
 		case AT_DropOids:		/* SET WITHOUT OIDS */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "SET WITHOUT OIDS");
 			/* Performs own recursion */
 			if (rel->rd_rel->relhasoids)
 			{
@@ -2807,38 +2853,82 @@ ATPrepCmd(List **wqueue, Relation rel, AlterTableCmd *cmd,
 			pass = AT_PASS_DROP;
 			break;
 		case AT_SetTableSpace:	/* SET TABLESPACE */
-			ATSimplePermissionsRelationOrIndex(rel);
+			ATSimplePermissions(rel, rk_relation_index, "SET TABLESPACE");
 			/* This command never recurses */
 			ATPrepSetTableSpace(tab, rel, cmd->name, lockmode);
 			pass = AT_PASS_MISC;	/* doesn't actually matter */
 			break;
 		case AT_SetRelOptions:	/* SET (...) */
+			ATSimplePermissions(rel, rk_relation_index, "SET (...)");
+			/* This command never recurses */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
 		case AT_ResetRelOptions:		/* RESET (...) */
-			ATSimplePermissionsRelationOrIndex(rel);
+			ATSimplePermissions(rel, rk_relation_index, "RESET (...)");
 			/* This command never recurses */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
 			break;
 		case AT_AddInherit:		/* INHERIT */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "INHERIT");
 			/* This command never recurses */
 			ATPrepAddInherit(rel);
 			pass = AT_PASS_MISC;
 			break;
-		case AT_EnableTrig:		/* ENABLE TRIGGER variants */
-		case AT_EnableAlwaysTrig:
-		case AT_EnableReplicaTrig:
+		case AT_EnableTrig:			/* ENABLE TRIGGER variants */
 		case AT_EnableTrigAll:
 		case AT_EnableTrigUser:
+			ATSimplePermissions(rel, rk_relation, "ENABLE TRIGGER");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
+		case AT_EnableAlwaysTrig:
+			ATSimplePermissions(rel, rk_relation, "ENABLE ALWAYS TRIGGER");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
+		case AT_EnableReplicaTrig:
+			ATSimplePermissions(rel, rk_relation, "ENABLE REPLICA TRIGGER");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_DisableTrig:	/* DISABLE TRIGGER variants */
 		case AT_DisableTrigAll:
 		case AT_DisableTrigUser:
+			ATSimplePermissions(rel, rk_relation, "DISABLE TRIGGER");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_EnableRule:		/* ENABLE/DISABLE RULE variants */
+			ATSimplePermissions(rel, rk_relation, "ENABLE RULE");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_EnableAlwaysRule:
+			ATSimplePermissions(rel, rk_relation, "ENABLE ALWAYS RULE");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_EnableReplicaRule:
+			ATSimplePermissions(rel, rk_relation, "ENABLE REPLICA RULE");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_DisableRule:
+			ATSimplePermissions(rel, rk_relation, "DISABLE RULE");
+			/* These commands never recurse */
+			/* No command-specific prep needed */
+			pass = AT_PASS_MISC;
+			break;
 		case AT_DropInherit:	/* NO INHERIT */
-			ATSimplePermissions(rel, false, false);
+			ATSimplePermissions(rel, rk_relation, "NO INHERIT");
 			/* These commands never recurse */
 			/* No command-specific prep needed */
 			pass = AT_PASS_MISC;
@@ -3559,66 +3649,15 @@ ATGetQueueEntry(List **wqueue, Relation rel)
 /*
  * ATSimplePermissions
  *
- * - Ensure that it is a relation (or possibly a view)
+ * - Check the relkind against the provided list
  * - Ensure this user is the owner
  * - Ensure that it is not a system table
  */
 static void
-ATSimplePermissions(Relation rel, bool allowView, bool allowType)
+ATSimplePermissions(Relation rel, const char *relkinds, const char *command)
 {
-	if (rel->rd_rel->relkind != RELKIND_RELATION)
-	{
-		if (allowView)
-		{
-			if (rel->rd_rel->relkind != RELKIND_VIEW)
-				ereport(ERROR,
-						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-						 errmsg("\"%s\" is not a table or view",
-								RelationGetRelationName(rel))));
-		}
-		else if (allowType)
-		{
-			if (rel->rd_rel->relkind != RELKIND_COMPOSITE_TYPE)
-				ereport(ERROR,
-						(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-						 errmsg("\"%s\" is not a table or composite type",
-								RelationGetRelationName(rel))));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("\"%s\" is not a table",
-							RelationGetRelationName(rel))));
-	}
-
-	/* Permissions checks */
-	if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
-		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
-					   RelationGetRelationName(rel));
-
-	if (!allowSystemTableMods && IsSystemRelation(rel))
-		ereport(ERROR,
-				(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
-				 errmsg("permission denied: \"%s\" is a system catalog",
-						RelationGetRelationName(rel))));
-}
-
-/*
- * ATSimplePermissionsRelationOrIndex
- *
- * - Ensure that it is a relation or an index
- * - Ensure this user is the owner
- * - Ensure that it is not a system table
- */
-static void
-ATSimplePermissionsRelationOrIndex(Relation rel)
-{
-	if (rel->rd_rel->relkind != RELKIND_RELATION &&
-		rel->rd_rel->relkind != RELKIND_INDEX)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table or index",
-						RelationGetRelationName(rel))));
+	if (!strchr(relkinds, rel->rd_rel->relkind))
+		ErrorWrongRelationType(rel, command);
 
 	/* Permissions checks */
 	if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
@@ -4449,10 +4488,7 @@ ATPrepSetStatistics(Relation rel, const char *colName, Node *newValue, LOCKMODE
 	 */
 	if (rel->rd_rel->relkind != RELKIND_RELATION &&
 		rel->rd_rel->relkind != RELKIND_INDEX)
-		ereport(ERROR,
-				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-				 errmsg("\"%s\" is not a table or index",
-						RelationGetRelationName(rel))));
+		ErrorWrongRelationType(rel, "ALTER COLUMN .. SET STATISTICS");
 
 	/* Permissions checks */
 	if (!pg_class_ownercheck(RelationGetRelid(rel), GetUserId()))
@@ -4692,7 +4728,7 @@ ATExecDropColumn(List **wqueue, Relation rel, const char *colName,
 
 	/* At top level, permission check was done in ATPrepCmd, else do it */
 	if (recursing)
-		ATSimplePermissions(rel, false, true);
+		ATSimplePermissions(rel, rk_relation_type, "DROP COLUMN");
 
 	/*
 	 * get the number of the attribute
@@ -4996,7 +5032,7 @@ ATAddCheckConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 
 	/* At top level, permission check was done in ATPrepCmd, else do it */
 	if (recursing)
-		ATSimplePermissions(rel, false, false);
+		ATSimplePermissions(rel, rk_relation, "ADD CONSTRAINT");
 
 	/*
 	 * Call AddRelationNewConstraints to do the work, making sure it works on
@@ -5940,7 +5976,7 @@ ATExecDropConstraint(Relation rel, const char *constrName,
 
 	/* At top level, permission check was done in ATPrepCmd, else do it */
 	if (recursing)
-		ATSimplePermissions(rel, false, false);
+		ATSimplePermissions(rel, rk_relation, "DROP CONSTRAINT");
 
 	conrel = heap_open(ConstraintRelationId, RowExclusiveLock);
 
@@ -6881,10 +6917,7 @@ ATExecChangeOwner(Oid relationOid, Oid newOwnerId, bool recursing, LOCKMODE lock
 				break;
 			/* FALL THRU */
 		default:
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("\"%s\" is not a table, view, or sequence",
-							NameStr(tuple_class->relname))));
+			ErrorWrongRelationType(target_rel, "OWNER TO");
 	}
 
 	/*
@@ -7188,10 +7221,8 @@ ATExecSetRelOptions(Relation rel, List *defList, bool isReset, LOCKMODE lockmode
 			(void) index_reloptions(rel->rd_am->amoptions, newOptions, true);
 			break;
 		default:
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("\"%s\" is not a table, index, or TOAST table",
-							RelationGetRelationName(rel))));
+			ErrorWrongRelationType(rel, isReset ?
+				"RESET (...)" : "SET (...)");
 			break;
 	}
 
@@ -7543,7 +7574,7 @@ ATExecAddInherit(Relation child_rel, RangeVar *parent, LOCKMODE lockmode)
 	 * Must be owner of both parent and child -- child was checked by
 	 * ATSimplePermissions call in ATPrepCmd
 	 */
-	ATSimplePermissions(parent_rel, false, false);
+	ATSimplePermissions(parent_rel, rk_relation, "INHERIT");
 
 	/* Permanent rels cannot inherit from temporary ones */
 	if (RelationUsesTempNamespace(parent_rel)
@@ -8186,10 +8217,7 @@ AlterTableNamespace(RangeVar *relation, const char *newschema,
 		case RELKIND_TOASTVALUE:
 			/* FALL THRU */
 		default:
-			ereport(ERROR,
-					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
-					 errmsg("\"%s\" is not a table, view, or sequence",
-							RelationGetRelationName(rel))));
+			ErrorWrongRelationType(rel, "SET SCHEMA");
 	}
 
 	/* get schema OID and check its permissions */
@@ -8376,6 +8404,22 @@ AlterSeqNamespaces(Relation classRel, Relation rel,
 	relation_close(depRel, AccessShareLock);
 }
 
+/*
+ * Emit the right error message for a SQL command issue on a relation of
+ * the wrong type.
+ */
+void
+ErrorWrongRelationType(Relation rel, const char *command)
+{
+	const struct wrongtypestrings *entry;
+
+	for (entry = wrongtypestringarray; entry->kind != '\0'; entry++)
+		if (entry->kind == rel->rd_rel->relkind)
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg(entry->wrongtype_message, command)));
+	elog(ERROR, "unexpected relkind: %c", rel->rd_rel->relkind);
+}
 
 /*
  * This code supports
diff --git a/src/include/commands/tablecmds.h b/src/include/commands/tablecmds.h
index ad932d3..d802128 100644
--- a/src/include/commands/tablecmds.h
+++ b/src/include/commands/tablecmds.h
@@ -60,6 +60,8 @@ extern AttrNumber *varattnos_map(TupleDesc olddesc, TupleDesc newdesc);
 extern AttrNumber *varattnos_map_schema(TupleDesc old, List *schema);
 extern void change_varattnos_of_a_node(Node *node, const AttrNumber *newattno);
 
+extern void ErrorWrongRelationType(Relation rel, const char *command);
+
 extern void register_on_commit_action(Oid relid, OnCommitAction action);
 extern void remove_on_commit_action(Oid relid);
 
diff --git a/src/test/regress/expected/alter_table.out b/src/test/regress/expected/alter_table.out
index e415730..b7917ea 100644
--- a/src/test/regress/expected/alter_table.out
+++ b/src/test/regress/expected/alter_table.out
@@ -599,9 +599,9 @@ ERROR:  cannot alter system column "oid"
 -- try creating a view and altering that, should fail
 create view myview as select * from atacc1;
 alter table myview alter column test drop not null;
-ERROR:  "myview" is not a table
+ERROR:  views do not support DROP NOT NULL
 alter table myview alter column test set not null;
-ERROR:  "myview" is not a table
+ERROR:  views do not support SET NOT NULL
 drop view myview;
 drop table atacc1;
 -- test inheritance
@@ -854,7 +854,7 @@ select * from myview;
 (0 rows)
 
 alter table myview drop d;
-ERROR:  "myview" is not a table or composite type
+ERROR:  views do not support DROP COLUMN
 drop view myview;
 -- test some commands to make sure they fail on the dropped column
 analyze atacc1(a);