Test line number for (??{$str}) regexp warnings

If the (??{}) does not occur on the same line as the match operator
(e.g., if we have /foo$qr/ and $qr has (??{}) in it), we need to
make sure warnings that occur when the return value of (??{}) is
compiled use the same line number as the /.../, since conceptually
it is part of matching, not part of returning.

I tried breaking this and making the line number wrong, but all
tests passed, showing that it is untested.  Most regcomp tests are in
t/re/reg_mesg.t, but that file does not have infrastructure for check-
ing line numbers.

diff --git a/t/lib/warnings/regcomp b/t/lib/warnings/regcomp
index 19b6b06..b55959e 100644 (file)
--- a/t/lib/warnings/regcomp
+++ b/t/lib/warnings/regcomp
@@ -1,3 +1,9 @@
   regcomp.c    These tests have been moved to t/re/reg_mesg.t
+               except for those that explicitly test line numbers.
 
 __END__
+use warnings 'regexp';
+$r=qr/(??{ q"\\b+" })/;
+"a" =~ /a$r/; # warning should come from this line
+EXPECT
+\b+ matches null string many times in regex; marked by <-- HERE in m/\b+ <-- HERE / at - line 3.