1 files changed, 13 insertions, 3 deletions
diff --git a/lib/regcomp.c b/lib/regcomp.c
index b607c85320f..122c3de58c3 100644
--- a/lib/regcomp.c
+++ b/lib/regcomp.c
@@ -2038,15 +2038,25 @@ peek_token_bracket (re_token_t *token, re_string_t *input, reg_syntax_t syntax)
     }
   switch (c)
     {
-    case '-':
-      token->type = OP_CHARSET_RANGE;
-      break;
     case ']':
       token->type = OP_CLOSE_BRACKET;
       break;
     case '^':
       token->type = OP_NON_MATCH_LIST;
       break;
+    case '-':
+      /* In V7 Unix grep and Unix awk and mawk, [...---...]
+         (3 adjacent minus signs) stands for a single minus sign.
+         Support that without breaking anything else.  */
+      if (! (re_string_cur_idx (input) + 2 < re_string_length (input)
+             && re_string_peek_byte (input, 1) == '-'
+             && re_string_peek_byte (input, 2) == '-'))
+        {
+          token->type = OP_CHARSET_RANGE;
+          break;
+        }
+      re_string_skip_bytes (input, 2);
+      FALLTHROUGH;
     default:
       token->type = CHARACTER;
     }