Have use VERSION and perl -E import a corresponding use builtin…

… bundle

builtin.c

@@ -12,6 +12,7 @@
  */
 
 #include "EXTERN.h"
+#define PERL_IN_BUILTIN_C
 #include "perl.h"
 
 #include "XSUB.h"
@@ -39,8 +40,8 @@ static void S_warn_experimental_builtin(pTHX_ const char *name)
 /* These three utilities might want to live elsewhere to be reused from other
  * code sometime
  */
-#define prepare_export_lexical()  S_prepare_export_lexical(aTHX)
-static void S_prepare_export_lexical(pTHX)
+void
+Perl_prepare_export_lexical(pTHX)
 {
     assert(PL_compcv);
 
@@ -59,8 +60,8 @@ static void S_export_lexical(pTHX_ SV *name, SV *sv)
     PL_curpad[off] = SvREFCNT_inc(sv);
 }
 
-#define finish_export_lexical()  S_finish_export_lexical(aTHX)
-static void S_finish_export_lexical(pTHX)
+void
+Perl_finish_export_lexical(pTHX)
 {
     intro_my();
 
@@ -603,8 +604,8 @@ static bool S_cv_is_builtin(pTHX_ CV *cv)
     return file && strEQ(file, __FILE__);
 }
 
-#define import_builtin_bundle(ver, do_unimport)  S_import_builtin_bundle(aTHX_ ver, do_unimport)
-static void S_import_builtin_bundle(pTHX_ U16 ver, bool do_unimport)
+void
+Perl_import_builtin_bundle(pTHX_ U16 ver, bool do_unimport)
 {
     SV *ampname = sv_newmortal();
 

embed.fnc

@@ -4076,6 +4076,13 @@ i	|bool	|PerlEnv_putenv |NN char *str
 #if defined(PERL_IN_AV_C)
 S	|MAGIC *|get_aux_mg	|NN AV *av
 #endif
+#if defined(PERL_IN_BUILTIN_C) || defined(PERL_IN_OP_C)
+p	|void	|finish_export_lexical
+p	|void	|import_builtin_bundle					\
+				|U16 ver				\
+				|bool do_unimport
+p	|void	|prepare_export_lexical
+#endif
 #if defined(PERL_IN_CLASS_C) || defined(PERL_IN_OP_C)    || \
     defined(PERL_IN_PAD_C)   || defined(PERL_IN_PERLY_C) || \
     defined(PERL_IN_TOKE_C)

embed.h

@@ -1199,6 +1199,11 @@
 #   if defined(PERL_IN_AV_C)
 #     define get_aux_mg(a)                      S_get_aux_mg(aTHX_ a)
 #   endif
+#   if defined(PERL_IN_BUILTIN_C) || defined(PERL_IN_OP_C)
+#     define finish_export_lexical()            Perl_finish_export_lexical(aTHX)
+#     define import_builtin_bundle(a,b)         Perl_import_builtin_bundle(aTHX_ a,b)
+#     define prepare_export_lexical()           Perl_prepare_export_lexical(aTHX)
+#   endif
 #   if defined(PERL_IN_CLASS_C) || defined(PERL_IN_GLOBALS_C) || \
        defined(PERL_IN_OP_C)    || defined(PERL_IN_PEEP_C)
 #     define ck_anoncode(a)                     Perl_ck_anoncode(aTHX_ a)

op.c

@@ -8046,6 +8046,16 @@ Perl_utilize(pTHX_ int aver, I32 floor, OP *version, OP *idop, OP *arg)
                 PL_hints &= ~HINT_STRICT_VARS;
         }
 
+        /* As an optimisation, there's no point scanning for changes of
+         * visible builtin functions when switching between versions earlier
+         * than v5.39, when any became visible at all
+         */
+        if ((shortver >= SHORTVER(5, 39)) || (PL_prevailing_version >= SHORTVER(5, 39))) {
+            prepare_export_lexical();
+            import_builtin_bundle(shortver, true);
+            finish_export_lexical();
+        }
+
         PL_prevailing_version = shortver;
     }
 

pod/perlfunc.pod

@@ -10161,12 +10161,18 @@ Compare with L<C<require>|/require VERSION>, which can do a similar check
 at run time.
 
 If the specified Perl version is 5.12 or higher, strictures are enabled
-lexically as with L<C<use strict>|strict>.  Similarly, if the specified
-Perl version is 5.35.0 or higher, L<warnings> are enabled.  Later use of
-C<use VERSION> will override all behavior of a previous C<use VERSION>,
-possibly removing the C<strict>, C<warnings>, and C<feature> added by it.
-C<use VERSION> does not load the F<feature.pm>, F<strict.pm>, or
-F<warnings.pm> files.
+lexically as with L<C<use strict>|strict>.
+
+If the specified Perl version is 5.35.0 or higher, L<warnings> are enabled.
+
+If the specified Perl version is 5.39.0 or higher, builtin functions are
+imported lexically as with L<C<use builtin>|builtin> with a corresponding
+version bundle.
+
+Later use of C<use VERSION> will override all behavior of a previous
+C<use VERSION>, possibly removing the C<strict>, C<warnings>, C<feature> and
+C<builtin> effects added by it.  C<use VERSION> does not load the
+F<feature.pm>, F<strict.pm>, F<warnings.pm> or F<builtin.pm> files.
 
 In the current implementation, any explicit use of C<use strict> or
 C<no strict> overrides C<use VERSION>, even if it comes before it.

pod/perlrun.pod

@@ -470,8 +470,8 @@ to use semicolons where you would in a normal program.
 X<-E>
 
 behaves just like L<-e|/-e commandline>, except that it implicitly
-enables all optional features (in the main compilation unit). See
-L<feature>.
+enables all optional features and builtin functions (in the main
+compilation unit). See L<feature> and L<builtin>.
 
 =item B<-f>
 X<-f> X<sitecustomize> X<sitecustomize.pl>

t/comp/use.t

@@ -6,7 +6,7 @@ BEGIN {
     $INC{"feature.pm"} = 1; # so we don't attempt to load feature.pm
 }
 
-print "1..85\n";
+print "1..88\n";
 
 # Can't require test.pl, as we're testing the use/require mechanism here.
 
@@ -170,6 +170,18 @@ ok $@, 'no strict vars allows ver decl to enable refs';
 eval 'no strict "vars"; use 5.012; ursine_word';
 ok $@, 'no strict vars allows ver decl to enable subs';
 
+# check that "use 5.39.0" and higher imports builtins
+{
+    my $result;
+
+    $result = eval 'use 5.39.0; my $t = true; $t eq "1"';
+    is ($@, "", 'builtin funcs available after use 5.39.0');
+    ok ($result, 'imported true is eq "1"');
+
+    eval 'use 5.39.0; use 5.36.0; my $t = true;';
+    like ($@, qr/^Bareword "true" not allowed while "strict subs" in use at /,
+        'builtin funcs are removed by use 5.36.0');
+}
 
 { use test_use }	# check that subparse saves pending tokens
 

t/run/switches.t

@@ -695,7 +695,12 @@ $TODO = '';  # the -E tests work on VMS
 $r = runperl(
     switches	=> [ '-E', '"say q(Hello, world!)"']
 );
-is( $r, "Hello, world!\n", "-E say" );
+is( $r, "Hello, world!\n", "-E enables 'say' feature" );
+
+$r = runperl(
+    switches	=> [ '-E', '"say reftype []"']
+);
+is( $r, "ARRAY\n", "-E enables 'reftype' builtin" );
 
 $r = runperl(
     switches    => [ '-nE', q("} END { say q/affe/") ],

toke.c

@@ -9240,7 +9240,8 @@ yyl_try(pTHX_ char *s)
             }
             if (PL_minus_E)
                 sv_catpvs(PL_linestr,
-                          "use feature ':" STRINGIFY(PERL_REVISION) "." STRINGIFY(PERL_VERSION) "';");
+                          "use feature ':" STRINGIFY(PERL_REVISION) "." STRINGIFY(PERL_VERSION) "'; "
+                          "use builtin ':" STRINGIFY(PERL_REVISION) "." STRINGIFY(PERL_VERSION) "';");
             if (PL_minus_n || PL_minus_p) {
                 sv_catpvs(PL_linestr, "LINE: while (<>) {"/*}*/);
                 if (PL_minus_l)