2 files changed, 17 insertions, 0 deletions
diff --git a/src/test/modules/test_regex/expected/test_regex.out b/src/test/modules/test_regex/expected/test_regex.out
index 731ba506d35..c44c717edf4 100644
--- a/src/test/modules/test_regex/expected/test_regex.out
+++ b/src/test/modules/test_regex/expected/test_regex.out
@@ -2071,6 +2071,20 @@ select * from test_regex('[\s\S]*', '012  3456789abc_*', 'LNPE');
  {"012  3456789abc_*"}
 (2 rows)
 
+-- bug #18708:
+select * from test_regex('(?:[^\d\D]){0}', '0123456789abc*', 'LNPQE');
+                             test_regex                             
+--------------------------------------------------------------------
+ {0,REG_UBOUNDS,REG_UBBS,REG_UNONPOSIX,REG_ULOCALE,REG_UEMPTYMATCH}
+ {""}
+(2 rows)
+
+select * from test_regex('[^\d\D]', '0123456789abc*', 'ILPE');
+                       test_regex                       
+--------------------------------------------------------
+ {0,REG_UBBS,REG_UNONPOSIX,REG_ULOCALE,REG_UIMPOSSIBLE}
+(1 row)
+
 -- check char classes' handling of newlines
 select * from test_regex('\s+', E'abc  \n  def', 'LP');
           test_regex           
diff --git a/src/test/modules/test_regex/sql/test_regex.sql b/src/test/modules/test_regex/sql/test_regex.sql
index 478fa2c5475..b2a847577e8 100644
--- a/src/test/modules/test_regex/sql/test_regex.sql
+++ b/src/test/modules/test_regex/sql/test_regex.sql
@@ -619,6 +619,9 @@ select * from test_regex('[^1\D0]', 'abc0123456789*', 'LPE');
 select * from test_regex('\W', '0123456789abc_*', 'LP');
 select * from test_regex('[\W]', '0123456789abc_*', 'LPE');
 select * from test_regex('[\s\S]*', '012  3456789abc_*', 'LNPE');
+-- bug #18708:
+select * from test_regex('(?:[^\d\D]){0}', '0123456789abc*', 'LNPQE');
+select * from test_regex('[^\d\D]', '0123456789abc*', 'ILPE');
 
 -- check char classes' handling of newlines
 select * from test_regex('\s+', E'abc  \n  def', 'LP');