regexec.c: utf8 doesn't match /i nonutf8 self

This is a continuation of [perl #78464].  It fixes it also for the /i
flag.  After this, a character should match itself in the regrepeat
function, even if one is in utf8 and the other isn't, for both /i and
not.

The solution is to move the code for handling /i into the non-i
structure so that the decisions about utf8 are all in one place.  When
the string is in utf8, it uses the utf8-fold function.

This has the added effect of fixing a few cases where a utf8 string did
not match a fold in a non-utf8 pattern.  I haven't added tests for
these, as it only fixes a few cases where this is a problem, and I'm
working on a comprehensive solution to the problem, accompanied by
extensive tests.

1 files changed, 4 insertions, 0 deletions

diff --git a/t/re/pat.t b/t/re/pat.t
index 46681040e5..d4bbbb8f20 100644
--- a/t/re/pat.t
+++ b/t/re/pat.t
@@ -1078,10 +1078,14 @@ sub run_tests {
         my $pattern = my $utf8_pattern = qr/((\xc0)+,?)/;
         utf8::upgrade($utf8_pattern);
         ok $c =~ $pattern, "\\xc0 =~ $pattern; Neither pattern nor target utf8";
+        ok $c =~ /$pattern/i, "\\xc0 =~ /$pattern/i; Neither pattern nor target utf8";
         ok $c =~ $utf8_pattern, "\\xc0 =~ $pattern; pattern utf8, target not";
+        ok $c =~ /$utf8_pattern/i, "\\xc0 =~ /$pattern/i; pattern utf8, target not";
         utf8::upgrade($c);
         ok $c =~ $pattern, "\\xc0 =~ $pattern; target utf8, pattern not";
+        ok $c =~ /$pattern/i, "\\xc0 =~ /$pattern/i; target utf8, pattern not";
         ok $c =~ $utf8_pattern, "\\xc0 =~ $pattern; Both target and pattern utf8";
+        ok $c =~ /$utf8_pattern/i, "\\xc0 =~ /$pattern/i; Both target and pattern utf8";
     }
 
     {