make sure the prototype actually matches

because:

a) I think it better demonstrates the fix, the following failed without
the patch:

./perl -Ilib -le 'my $proto = "\x{30cd}"; eval "sub f($proto) {}"; print prototype(\&f); print prototype(\&f) eq $proto'

b) I can envision bugs that might preserve UTF-8 but mis-manage the content

1 files changed, 2 insertions, 1 deletions

diff --git a/t/op/lexsub.t b/t/op/lexsub.t
index c77b2ff0a4..d717f42999 100644
--- a/t/op/lexsub.t
+++ b/t/op/lexsub.t
@@ -8,7 +8,7 @@ BEGIN {
     *bar::like = *like;
 }
 no warnings 'deprecated';
-plan 137;
+plan 138;
 
 # -------------------- Errors with feature disabled -------------------- #
 
@@ -432,6 +432,7 @@ package main;
   my $coderef = eval "my sub foo (\$\x{30cd}) {1}; \\&foo";
   my $proto = prototype $coderef;
   ok(utf8::is_utf8($proto), "my sub with UTF8 proto maintains the UTF8ness");
+  is($proto, "\$\x{30cd}", "check the prototypes actually match");
 }
 {
   my sub if() { 44 }