Make setting ${^ENCODING} to a defined value fatal

This has been deprecated since 5.22 and a no-op since 5.26.

Remove the now-obsolete t/uni/heavy.t test, which only tested that
utf8_heavy.pl didn't fail to load when ${^ENCODING} was set.

3 files changed, 9 insertions, 3 deletions

diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index eeb75c8e77..46b0fe0719 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -96,6 +96,10 @@ bitwise string operators
 
 Code points over 0xFF do not make sense for bitwise operators.
 
+=head2 Setting C<${^ENCODING}> to a defined value is now illegal
+
+This has been deprecated since Perl 5.22 and a no-op since Perl 5.26.
+
 =head1 Deprecations
 
 XXX Any deprecated features, syntax, modules etc. should be listed here.
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index cf9801e177..7e8d827216 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -2112,12 +2112,13 @@ unlikely to be what you want.
 described in L<perlunicode> and L<perlre>.  You used C<\p> or C<\P> in
 a regular expression without specifying the property name.
 
-=item ${^ENCODING} is no longer supported. Its use will be fatal in Perl 5.28
+=item ${^ENCODING} is no longer supported
 
-(D deprecated) The special variable C<${^ENCODING}>, formerly used to implement
+(F) The special variable C<${^ENCODING}>, formerly used to implement
 the C<encoding> pragma, is no longer supported as of Perl 5.26.0.
 
-Setting this variable will become a fatal error in Perl 5.28.
+Setting it to anything other than C<undef> is a fatal error as of Perl
+5.28.
 
 =item entering effective %s failed
 
diff --git a/pod/perlvar.pod b/pod/perlvar.pod
index 0bd747184f..9ce9430b6b 100644
--- a/pod/perlvar.pod
+++ b/pod/perlvar.pod
@@ -1990,6 +1990,7 @@ undefines the variable during the scope of execution of the including
 function.
 
 This variable was added in Perl 5.8.2 and removed in 5.26.0.
+Setting it to anything other than C<undef> was made fatal in Perl 5.28.0.
 
 =item ${^GLOBAL_PHASE}
 X<${^GLOBAL_PHASE}>