Remove experimental warnings from sub :const attribute

lib/B/Deparse.t

@@ -887,7 +887,6 @@ my $f = sub {
 } ;
 ####
 # anonconst
-# CONTEXT no warnings 'experimental::const_attr';
 my $f = sub : const {
     123;
 }

pod/perldiag.pod

@@ -2041,13 +2041,6 @@ to define an overloaded constant, or when trying to find the
 character name specified in the C<\N{...}> escape.  Perhaps you
 forgot to load the corresponding L<overload> pragma?
 
-=item :const is experimental
-
-(S experimental::const_attr) The "const" attribute is experimental.
-If you want to use the feature, disable the warning with C<no warnings
-'experimental::const_attr'>, but know that in doing so you are taking
-the risk that your code may break in a future Perl version.
-
 =item :const is not permitted on named subroutines
 
 (F) The "const" attribute causes an anonymous subroutine to be run and

pod/perlexperiment.pod

@@ -55,18 +55,6 @@ L<[perl #14150]|https://github.com/Perl/perl5/issues/14150>.
 
 See also: L<perlref/Assigning to References>
 
-=item The "const" attribute
-
-Introduced in Perl 5.22.0
-
-Using this feature triggers warnings in the category
-C<experimental::const_attr>.
-
-The ticket for this experiment is
-L<[perl #14428]|https://github.com/Perl/perl5/issues/14428>.
-
-See also: L<perlsub/Constant Functions>
-
 =item use re 'strict';
 
 Introduced in Perl 5.22.0
@@ -372,6 +360,14 @@ Introduced in Perl 5.34.0.
 
 Accepted in Perl 5.40 when not using the optional C<finally> block.
 
+=item The "const" attribute
+
+Introduced in Perl 5.22.0
+
+Accepted in Perl 5.40
+
+See also: L<perlsub/Constant Functions>
+
 =back
 
 =head2 Removed features

pod/perlsub.pod

@@ -1785,11 +1785,11 @@ aside from where it is declared.
         *ALSO_INLINED = sub () { $x };
     }
 
-Perl 5.22 also introduces the experimental "const" attribute as an
-alternative.  (Disable the "experimental::const_attr" warnings if you want
-to use it.)  When applied to an anonymous subroutine, it forces the sub to
-be called when the C<sub> expression is evaluated.  The return value is
-captured and turned into a constant subroutine:
+Perl 5.22 also introduced the "const" attribute as an alternative.  It was
+initially experimental, but made stable in Perl 5.40.  When applied to an
+anonymous subroutine, it forces the sub to be called when the C<sub>
+expression is evaluated.  The return value is captured and turned into a
+constant subroutine:
 
     my $x = 54321;
     *INLINED = sub : const { $x };

regen/warnings.pl

@@ -194,6 +194,7 @@ BEGIN
   experimental::script_run
   experimental::isa
   experimental::smartmatch
+  experimental::const_attr
 );
 
 ###########################################################################

t/op/anonconst.t

@@ -6,17 +6,6 @@ BEGIN {
     set_up_inc("../lib");
 }
 
-plan 8;
-
-{
-    my $w;
-    local $SIG{__WARN__} = sub { $w .= shift };
-    eval '+sub : const {}';
-    like $w, qr/^:const is experimental at /, 'experimental warning';
-}
-
-no warnings 'experimental::const_attr';
-
 push @subs, sub :const{$_} for 1..10;
 is join(" ", map &$_, @subs), "1 2 3 4 5 6 7 8 9 10",
   ':const capturing global $_';
@@ -49,3 +38,5 @@ like $@, qr/^:const is not permitted on named subroutines at /,
 eval 'sub baz : const { }';
 like $@, qr/^:const is not permitted on named subroutines at /,
     ':const on named sub';
+
+done_testing;

toke.c

@@ -12857,10 +12857,6 @@ S_apply_builtin_cv_attribute(pTHX_ CV *cv, OP *o)
     else if(memEQs(SvPVX(sv), len, "method"))
         CvNOWARN_AMBIGUOUS_on(cv);
     else if(memEQs(SvPVX(sv), len, "const")) {
-        Perl_ck_warner_d(aTHX_
-            packWARN(WARN_EXPERIMENTAL__CONST_ATTR),
-           ":const is experimental"
-        );
         CvANONCONST_on(cv);
         if (!CvANON(cv))
             yyerror(":const is not permitted on named subroutines");