put shadowing warnings in their own category

As proposed in [perl #125330].

9 files changed, 52 insertions, 34 deletions

diff --git a/ext/XS-APItest/t/loopblock.t b/ext/XS-APItest/t/loopblock.t
index 3b688bc811..7f654a5424 100644
--- a/ext/XS-APItest/t/loopblock.t
+++ b/ext/XS-APItest/t/loopblock.t
@@ -70,7 +70,7 @@ eval q{
 	my $x = "a";
 	$t .= $x;
 	do {
-		no warnings "misc";
+		no warnings "shadow";
 		$t .= $x;
 		my $x = "b";
 		$t .= $x;
diff --git a/ext/XS-APItest/t/looprest.t b/ext/XS-APItest/t/looprest.t
index e37ef87941..aa3116daa8 100644
--- a/ext/XS-APItest/t/looprest.t
+++ b/ext/XS-APItest/t/looprest.t
@@ -66,7 +66,7 @@ eval q{
 	my $x = "a";
 	$t .= $x;
 	do {
-		no warnings "misc";
+		no warnings "shadow";
 		$t .= $x;
 		my $x = "b";
 		$t .= $x;
diff --git a/lib/warnings.pm b/lib/warnings.pm
index 64e6448a08..c6bbe8c95d 100644
--- a/lib/warnings.pm
+++ b/lib/warnings.pm
@@ -5,7 +5,7 @@
 
 package warnings;
 
-our $VERSION = "1.38";
+our $VERSION = "1.39";
 
 # Verify that we're called correctly so that warnings will work.
 # Can't use Carp, since Carp uses us!
@@ -96,6 +96,9 @@ our %Offsets = (
 
     # Warnings Categories added in Perl 5.025
     'experimental::declared_refs'	=> 132,
+
+    # Warnings Categories added in Perl 5.027
+    'shadow'				=> 134,
 );
 
 our %Bits = (
@@ -153,6 +156,7 @@ our %Bits = (
     'reserved'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x04\x00\x00\x00\x00\x00\x00\x00", # [37]
     'semicolon'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00", # [38]
     'severe'				=> "\x00\x00\x00\x00\x00\x54\x05\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [21..25]
+    'shadow'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x40", # [67]
     'signal'				=> "\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [26]
     'substr'				=> "\x00\x00\x00\x00\x00\x00\x40\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [27]
     'surrogate'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x10\x00\x00\x00\x00", # [50]
@@ -223,6 +227,7 @@ our %DeadBits = (
     'reserved'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x08\x00\x00\x00\x00\x00\x00\x00", # [37]
     'semicolon'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00", # [38]
     'severe'				=> "\x00\x00\x00\x00\x00\xa8\x0a\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [21..25]
+    'shadow'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x80", # [67]
     'signal'				=> "\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [26]
     'substr'				=> "\x00\x00\x00\x00\x00\x00\x80\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", # [27]
     'surrogate'				=> "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x20\x00\x00\x00\x00", # [50]
@@ -241,7 +246,7 @@ our %DeadBits = (
 # These are used by various things, including our own tests
 our $NONE				=  "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0";
 our $DEFAULT				=  "\x10\x01\x00\x00\x00\x50\x04\x00\x00\x00\x00\x00\x00\x55\x51\x55\x10", # [2,4,22,23,25,52..56,58..63,66]
-our $LAST_BIT				=  134 ;
+our $LAST_BIT				=  136 ;
 our $BYTES				=  17 ;
 
 sub Croaker
@@ -811,6 +816,8 @@ The current hierarchy is:
          |                 |
          |                 +- malloc
          |
+         +- shadow
+         |
          +- signal
          |
          +- substr
diff --git a/pad.c b/pad.c
index 9c20d66e94..d1311e2e0b 100644
--- a/pad.c
+++ b/pad.c
@@ -857,7 +857,7 @@ S_pad_check_dup(pTHX_ PADNAME *name, U32 flags, const HV *ourstash)
 
     assert((flags & ~padadd_OUR) == 0);
 
-    if (PadnamelistMAX(PL_comppad_name) < 0 || !ckWARN(WARN_MISC))
+    if (PadnamelistMAX(PL_comppad_name) < 0 || !ckWARN(WARN_SHADOW))
 	return; /* nothing to check */
 
     svp = PadnamelistARRAY(PL_comppad_name);
@@ -875,7 +875,7 @@ S_pad_check_dup(pTHX_ PADNAME *name, U32 flags, const HV *ourstash)
 	    if (is_our && (SvPAD_OUR(sv)))
 		break; /* "our" masking "our" */
 	    /* diag_listed_as: "%s" variable %s masks earlier declaration in same %s */
-	    Perl_warner(aTHX_ packWARN(WARN_MISC),
+	    Perl_warner(aTHX_ packWARN(WARN_SHADOW),
 		"\"%s\" %s %" PNf " masks earlier declaration in same %s",
 		(   is_our                         ? "our"   :
                     PL_parser->in_my == KEY_my     ? "my"    :
@@ -901,10 +901,10 @@ S_pad_check_dup(pTHX_ PADNAME *name, U32 flags, const HV *ourstash)
 		&& SvOURSTASH(sv) == ourstash
 		&& memEQ(PadnamePV(sv), PadnamePV(name), PadnameLEN(name)))
 	    {
-		Perl_warner(aTHX_ packWARN(WARN_MISC),
+		Perl_warner(aTHX_ packWARN(WARN_SHADOW),
 		    "\"our\" variable %" PNf " redeclared", PNfARG(sv));
 		if (off <= PL_comppad_name_floor)
-		    Perl_warner(aTHX_ packWARN(WARN_MISC),
+		    Perl_warner(aTHX_ packWARN(WARN_SHADOW),
 			"\t(Did you mean \"local\" instead of \"our\"?)\n");
 		break;
 	    }
diff --git a/pod/perldelta.pod b/pod/perldelta.pod
index c4c85746b7..9e8b4360ed 100644
--- a/pod/perldelta.pod
+++ b/pod/perldelta.pod
@@ -236,6 +236,12 @@ XXX Changes (i.e. rewording) of diagnostic messages go here
 
 XXX Describe change here
 
+=item *
+
+Warnings that a variable or subroutine "masks earlier declaration in same
+...", or that an C<our> variable has been redeclared, have been moved to a
+new warnings category "shadow".  Previously they were in category "misc".
+
 =back
 
 =head1 Utility Changes
diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index 528fd40339..c38fc0f032 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -2047,7 +2047,7 @@ some such.
 
 =item (Did you mean "local" instead of "our"?)
 
-(W misc) Remember that "our" does not localize the declared global
+(W shadow) Remember that "our" does not localize the declared global
 variable.  You have declared it again in the same lexical scope, which
 seems superfluous.
 
@@ -4402,7 +4402,7 @@ have a specific default.  You probably want "$a = undef".
 
 =item "our" variable %s redeclared
 
-(W misc) You seem to have already declared the same global once before
+(W shadow) You seem to have already declared the same global once before
 in the current lexical scope.
 
 =item Out of memory!
@@ -5797,7 +5797,7 @@ being executed, so its &a is not available for capture.
 
 =item "%s" subroutine &%s masks earlier declaration in same %s
 
-(W misc) A "my" or "state" subroutine has been redeclared in the
+(W shadow) A "my" or "state" subroutine has been redeclared in the
 current scope or statement, effectively eliminating all access to
 the previous instance.  This is almost always a typographical error.
 Note that the earlier subroutine will still exist until the end of
@@ -7326,7 +7326,7 @@ See L<re>.
 
 =item "%s" variable %s masks earlier declaration in same %s
 
-(W misc) A "my", "our" or "state" variable has been redeclared in the
+(W shadow) A "my", "our" or "state" variable has been redeclared in the
 current scope or statement, effectively eliminating all access to the
 previous instance.  This is almost always a typographical error.  Note
 that the earlier variable will still exist until the end of the scope
diff --git a/regen/warnings.pl b/regen/warnings.pl
index b9692ab5ea..b090d4b862 100644
--- a/regen/warnings.pl
+++ b/regen/warnings.pl
@@ -16,7 +16,7 @@
 #
 # This script is normally invoked from regen.pl.
 
-$VERSION = '1.38';
+$VERSION = '1.39';
 
 BEGIN {
     require './regen/regen_lib.pl';
@@ -112,6 +112,7 @@ my $tree = {
         'missing'       => [ 5.021, DEFAULT_OFF],
         'redundant'     => [ 5.021, DEFAULT_OFF],
         'locale'        => [ 5.021, DEFAULT_ON],
+        'shadow'        => [ 5.027, DEFAULT_OFF],
 
          #'default'     => [ 5.008, DEFAULT_ON ],
 }]};
diff --git a/t/lib/warnings/pad b/t/lib/warnings/pad
index 4e31fe338b..bd8e9c0675 100644
--- a/t/lib/warnings/pad
+++ b/t/lib/warnings/pad
@@ -29,7 +29,7 @@
     
 __END__
 # pad.c
-use warnings 'misc' ;
+use warnings 'shadow' ;
 my $x ;
 my $x ;
 my $y = my $y ;
@@ -37,7 +37,7 @@ my $p ;
 package X ;
 my $p ;
 package main ;
-no warnings 'misc' ;
+no warnings 'shadow' ;
 my $x ;
 my $y ;
 my $p ;
@@ -47,7 +47,7 @@ EXPECT
 "my" variable $p masks earlier declaration in same scope at - line 8.
 ########
 # pad.c
-use warnings 'misc' ;
+use warnings 'shadow' ;
 our $x ;
 my $x ;
 our $y = my $y ;
@@ -55,7 +55,7 @@ our $p ;
 package X ;
 my $p ;
 package main ;
-no warnings 'misc' ;
+no warnings 'shadow' ;
 our $z ;
 my $z ;
 our $t = my $t ;
@@ -68,7 +68,7 @@ EXPECT
 "my" variable $p masks earlier declaration in same scope at - line 8.
 ########
 # pad.c
-use warnings 'misc' ;
+use warnings 'shadow' ;
 my $x ;
 our $x ;
 my $y = our $y ;
@@ -76,7 +76,7 @@ my $p ;
 package X ;
 our $p ;
 package main ;
-no warnings 'misc' ;
+no warnings 'shadow' ;
 my $z ;
 our $z ;
 my $t = our $t ;
@@ -234,7 +234,7 @@ our $y;
 sub { $x = $y }->();  # should not warn about $y being unavailable
 EXPECT
 ########
-use warnings 'misc' ;
+use warnings 'shadow' ;
 my $x;
 {
     my $x;
@@ -242,7 +242,7 @@ my $x;
 EXPECT
 ########
 # pad.c
-use warnings 'misc' ;
+use warnings 'shadow' ;
 our $x ;
 our $x ;
 our $y = our $y ;
@@ -250,7 +250,7 @@ our $p ;
 package X ;
 our $p ;
 package main ;
-no warnings 'misc' ;
+no warnings 'shadow' ;
 our $a ;
 our $a ;
 our $b = our $b ;
@@ -261,13 +261,13 @@ EXPECT
 "our" variable $x redeclared at - line 4.
 "our" variable $y redeclared at - line 5.
 ########
-use warnings 'misc' ;
+use warnings 'shadow' ;
 our $x;
 {
     our $x;
 }
 our $x;
-no warnings 'misc' ;
+no warnings 'shadow' ;
 our $y;
 {
     our $y;
@@ -278,36 +278,36 @@ EXPECT
 	(Did you mean "local" instead of "our"?)
 "our" variable $x redeclared at - line 6.
 ########
-use warnings 'misc' ;
+use warnings 'shadow' ;
 our $x;
 {
     my $x;
 }
-no warnings 'misc' ;
+no warnings 'shadow' ;
 our $y;
 {
     my $y;
 }
 EXPECT
 ########
-use warnings 'misc' ;
+use warnings 'shadow' ;
 my $x;
 {
     our $x;
 }
-no warnings 'misc' ;
+no warnings 'shadow' ;
 my $y;
 {
     our $y;
 }
 EXPECT
 ########
-use warnings 'misc' ;
+use warnings 'shadow' ;
 my $x;
 {
     my $x;
 }
-no warnings 'misc' ;
+no warnings 'shadow' ;
 my $y;
 {
     my $y;
@@ -320,13 +320,13 @@ use warnings;
 our $x unless $x;
 EXPECT
 ########
-use warnings 'misc';
+use warnings 'shadow';
 our $qunckkk;
 our $_;
 package clank_est;
 our $qunckkk;
 our $_;
-no warnings 'misc';
+no warnings 'shadow';
 our $ouch;
 our $_;
 package whack;
@@ -335,7 +335,7 @@ our $_;
 EXPECT
 "our" variable $_ redeclared at - line 6.
 ########
-use warnings 'misc';
+use warnings 'shadow';
 BEGIN { binmode STDERR, 'utf8'; }
 {
     use utf8;
@@ -345,7 +345,7 @@ BEGIN { binmode STDERR, 'utf8'; }
 EXPECT
 "my" variable $ニコニコ masks earlier declaration in same scope at - line 6.
 ########
-use warnings 'misc';
+use warnings 'shadow';
 BEGIN { binmode STDERR, 'utf8'; }
 {
     use utf8;
diff --git a/warnings.h b/warnings.h
index c2831a2938..9ea5c8fb32 100644
--- a/warnings.h
+++ b/warnings.h
@@ -115,6 +115,10 @@
 
 #define WARN_EXPERIMENTAL__DECLARED_REFS 66
 
+/* Warnings Categories added in Perl 5.027 */
+
+#define WARN_SHADOW			 67
+
 #define WARNsize			 17
 #define WARN_ALLstring			 "\125\125\125\125\125\125\125\125\125\125\125\125\125\125\125\125\125"
 #define WARN_NONEstring			 "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"