diff --git a/src/backend/utils/adt/regproc.c b/src/backend/utils/adt/regproc.c
index 59e5dc8..65cd5ed 100644
--- a/src/backend/utils/adt/regproc.c
+++ b/src/backend/utils/adt/regproc.c
@@ -1569,6 +1569,7 @@ Datum
 regrolein(PG_FUNCTION_ARGS)
 {
 	char	   *role_name_or_oid = PG_GETARG_CSTRING(0);
+	List	   *names;
 	Oid			result;
 
 	/* '-' ? */
@@ -1586,7 +1587,14 @@ regrolein(PG_FUNCTION_ARGS)
 	}
 
 	/* Normal case: see if the name matches any pg_authid entry. */
-	result = get_role_oid(role_name_or_oid, false);
+	names = stringToQualifiedNameList(role_name_or_oid);
+
+	if (list_length(names) != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_NAME),
+				 errmsg("invalid name syntax")));
+
+	result = get_role_oid(strVal(linitial(names)), false);
 
 	PG_RETURN_OID(result);
 }
@@ -1600,9 +1608,17 @@ Datum
 to_regrole(PG_FUNCTION_ARGS)
 {
 	char	   *role_name = PG_GETARG_CSTRING(0);
+	List	   *names;
 	Oid			result;
 
-	result = get_role_oid(role_name, true);
+	names = stringToQualifiedNameList(role_name);
+
+	if (list_length(names) != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_NAME),
+				 errmsg("invalid name syntax")));
+
+	result = get_role_oid(strVal(linitial(names)), true);
 
 	if (OidIsValid(result))
 		PG_RETURN_OID(result);
@@ -1668,6 +1684,7 @@ Datum
 regnamespacein(PG_FUNCTION_ARGS)
 {
 	char	   *nsp_name_or_oid = PG_GETARG_CSTRING(0);
+	List	   *names;
 	Oid			result = InvalidOid;
 
 	/* '-' ? */
@@ -1685,7 +1702,14 @@ regnamespacein(PG_FUNCTION_ARGS)
 	}
 
 	/* Normal case: see if the name matches any pg_namespace entry. */
-	result = get_namespace_oid(nsp_name_or_oid, false);
+	names = stringToQualifiedNameList(nsp_name_or_oid);
+
+	if (list_length(names) != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_NAME),
+				 errmsg("invalid name syntax")));
+
+	result = get_namespace_oid(strVal(linitial(names)), false);
 
 	PG_RETURN_OID(result);
 }
@@ -1699,9 +1723,17 @@ Datum
 to_regnamespace(PG_FUNCTION_ARGS)
 {
 	char	   *nsp_name = PG_GETARG_CSTRING(0);
+	List	   *names;
 	Oid			result;
 
-	result = get_namespace_oid(nsp_name, true);
+	names = stringToQualifiedNameList(nsp_name);
+
+	if (list_length(names) != 1)
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_NAME),
+				 errmsg("invalid name syntax")));
+
+	result = get_namespace_oid(strVal(linitial(names)), true);
 
 	if (OidIsValid(result))
 		PG_RETURN_OID(result);
diff --git a/src/test/regress/expected/regproc.out b/src/test/regress/expected/regproc.out
index 8c734f4..e67dec0 100644
--- a/src/test/regress/expected/regproc.out
+++ b/src/test/regress/expected/regproc.out
@@ -137,6 +137,14 @@ SELECT regtype('pg_catalog.int4');
  integer
 (1 row)
 
+SELECT regrole('pg_catalog.regtestrole');
+ERROR:  invalid name syntax
+LINE 1: SELECT regrole('pg_catalog.regtestrole');
+                       ^
+SELECT regnamespace('pg_catalog.pg_catalog');
+ERROR:  invalid name syntax
+LINE 1: SELECT regnamespace('pg_catalog.pg_catalog');
+                            ^
 SELECT to_regoper('pg_catalog.||/');
  to_regoper 
 ------------
@@ -167,6 +175,10 @@ SELECT to_regtype('pg_catalog.int4');
  integer
 (1 row)
 
+SELECT to_regrole('pg_catalog.regtestrole');
+ERROR:  invalid name syntax
+SELECT to_regnamespace('pg_catalog.pg_catalog');
+ERROR:  invalid name syntax
 /* If objects don't exist, raise errors. */
 DROP ROLE regtestrole;
 -- without schemaname
diff --git a/src/test/regress/sql/regproc.sql b/src/test/regress/sql/regproc.sql
index 8edaf15..0f398ea 100644
--- a/src/test/regress/sql/regproc.sql
+++ b/src/test/regress/sql/regproc.sql
@@ -33,12 +33,16 @@ SELECT regproc('pg_catalog.now');
 SELECT regprocedure('pg_catalog.abs(numeric)');
 SELECT regclass('pg_catalog.pg_class');
 SELECT regtype('pg_catalog.int4');
+SELECT regrole('pg_catalog.regtestrole');
+SELECT regnamespace('pg_catalog.pg_catalog');
 
 SELECT to_regoper('pg_catalog.||/');
 SELECT to_regproc('pg_catalog.now');
 SELECT to_regprocedure('pg_catalog.abs(numeric)');
 SELECT to_regclass('pg_catalog.pg_class');
 SELECT to_regtype('pg_catalog.int4');
+SELECT to_regrole('pg_catalog.regtestrole');
+SELECT to_regnamespace('pg_catalog.pg_catalog');
 
 /* If objects don't exist, raise errors. */