Introduce C<use feature "unicode_strings">

This turns on the unicode semantics for uc/lc/ucfirst/lcfirst
operations on strings without the UTF8 bit set but with ASCII
characters higher than 127. This replaces the "legacy" pragma
experiment.

Note that currently this feature sets both a bit in $^H and
a (unused) key in %^H. The bit in $^H could be replaced by
a flag on the uc/lc/etc op. It's probably not feasible to
test a key in %^H in pp_uc in friends each time we want to
know which semantics to apply.

2 files changed, 20 insertions, 1 deletions

diff --git a/t/lib/feature/bundle b/t/lib/feature/bundle
index a869c7541f..11fde323ed 100644
--- a/t/lib/feature/bundle
+++ b/t/lib/feature/bundle
@@ -7,6 +7,25 @@ say "Hello", "world";
 EXPECT
 Helloworld
 ########
+# Standard feature bundle, no 5.11
+use feature ":5.10";
+say ord uc chr 233;
+EXPECT
+233
+########
+# Standard feature bundle, 5.11
+use feature ":5.11";
+say ord uc chr 233;
+EXPECT
+201
+########
+# Standard feature bundle, 5.11
+use feature ":5.11";
+use utf8;
+say ord "\ué"; # this is utf8
+EXPECT
+201
+########
 # more specific: 5.10.0 maps to 5.10
 use feature ":5.10.0";
 say "Hello", "world";
diff --git a/t/uni/overload.t b/t/uni/overload.t
index da9b07beb7..7bf48414e1 100644
--- a/t/uni/overload.t
+++ b/t/uni/overload.t
@@ -35,7 +35,7 @@ package main;
 
 # These tests are based on characters 128-255 not having latin1, and hence
 # Unicode, semantics
-use legacy 'unicode8bit';
+# no feature "unicode_strings";
 
 # Bug 34297
 foreach my $t ("ASCII", "B\366se") {