2 files changed, 18 insertions, 3 deletions
diff --git a/src/backend/parser/parse_node.c b/src/backend/parser/parse_node.c
index 6ffbd767275..e0ea43a8104 100644
--- a/src/backend/parser/parse_node.c
+++ b/src/backend/parser/parse_node.c
@@ -226,6 +226,18 @@ transformArrayType(Oid *arrayType, int32 *arrayTypmod)
 	 */
 	*arrayType = getBaseTypeAndTypmod(*arrayType, arrayTypmod);
 
+	/*
+	 * We treat int2vector and oidvector as though they were domains over
+	 * int2[] and oid[].  This is needed because array slicing could create an
+	 * array that doesn't satisfy the dimensionality constraints of the
+	 * xxxvector type; so we want the result of a slice operation to be
+	 * considered to be of the more general type.
+	 */
+	if (*arrayType == INT2VECTOROID)
+		*arrayType = INT2ARRAYOID;
+	else if (*arrayType == OIDVECTOROID)
+		*arrayType = OIDARRAYOID;
+
 	/* Get the type tuple for the array */
 	type_tuple_array = SearchSysCache1(TYPEOID, ObjectIdGetDatum(*arrayType));
 	if (!HeapTupleIsValid(type_tuple_array))
@@ -263,6 +275,7 @@ transformArrayType(Oid *arrayType, int32 *arrayTypmod)
  * For both cases, if the source array is of a domain-over-array type,
  * the result is of the base array type or its element type; essentially,
  * we must fold a domain to its base type before applying subscripting.
+ * (Note that int2vector and oidvector are treated as domains here.)
  *
  * pstate		Parse state
  * arrayBase	Already-transformed expression for the array as a whole
diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c
index 9c6c202c8e6..d56e00ffde6 100644
--- a/src/backend/parser/parse_target.c
+++ b/src/backend/parser/parse_target.c
@@ -839,18 +839,20 @@ transformAssignmentSubscripts(ParseState *pstate,
 	/* If target was a domain over array, need to coerce up to the domain */
 	if (arrayType != targetTypeId)
 	{
+		Oid			resulttype = exprType(result);
+
 		result = coerce_to_target_type(pstate,
-									   result, exprType(result),
+									   result, resulttype,
 									   targetTypeId, targetTypMod,
 									   COERCION_ASSIGNMENT,
 									   COERCE_IMPLICIT_CAST,
 									   -1);
-		/* probably shouldn't fail, but check */
+		/* can fail if we had int2vector/oidvector, but not for true domains */
 		if (result == NULL)
 			ereport(ERROR,
 					(errcode(ERRCODE_CANNOT_COERCE),
 					 errmsg("cannot cast type %s to %s",
-							format_type_be(exprType(result)),
+							format_type_be(resulttype),
 							format_type_be(targetTypeId)),
 					 parser_errposition(pstate, location)));
 	}