deprecate smart matching for hints, but silence warnings

New versions of perl are deprecating smart match, and they should
eventually be removed. Update the code to silence the warnings related
to smart match to properly disable "deprecated" warnings internally.

Add our own deprecation warnings on all versions of perl that support
smartmatch.

Stop supporting smart match in perl 5.41.

lib/Fatal.pm

@@ -17,7 +17,12 @@ use autodie::Util qw(
   on_end_of_compile_scope
 );
 
-use constant SMARTMATCH_ALLOWED => ( $] >= 5.010 );
+use constant SMARTMATCH_ALLOWED => ( $] >= 5.010 && $] < 5.041 );
+use constant SMARTMATCH_CATEGORY => (
+      !SMARTMATCH_ALLOWED || $] < 5.018 ? undef
+    : exists $warnings::Offsets{'experimental::smartmatch'} ? 'experimental::smartmatch'
+    : 'deprecated'
+);
 
 use constant LEXICAL_TAG => q{:lexical};
 use constant VOID_TAG    => q{:void};
@@ -48,7 +53,9 @@ use constant ERROR_AUTODIE_CONFLICT => q{"no autodie '%s'" is not allowed while
 
 use constant ERROR_FATAL_CONFLICT => q{"use Fatal '%s'" is not allowed while "no autodie '%s'" is in effect};
 
-use constant ERROR_58_HINTS => q{Non-subroutine %s hints for %s are not supported under Perl 5.8.x};
+use constant ERROR_SMARTMATCH_HINTS => q{%s hints for %s must be code, regexp, or undef. Use of other values is deprecated and only supported on Perl 5.10 through 5.40.};
+
+use constant WARNING_SMARTMATCH_DEPRECATED => q{%s hints for %s must be code, regexp, or undef. Use of other values is deprecated and will be removed before Perl 5.42.};
 
 # Older versions of IPC::System::Simple don't support all the
 # features we need.
@@ -1089,8 +1096,6 @@ sub _one_invocation {
 
     my $code = qq[
         no warnings qw(unopened uninitialized numeric);
-        no if \$\] >= 5.017011, warnings => "experimental::smartmatch";
-        no if \$warnings::Offsets{"deprecated::smartmatch"}, warnings => "deprecated";
 
         if (wantarray) {
             my \@results = $call(@argv);
@@ -1111,11 +1116,21 @@ sub _one_invocation {
 
             $match = q[ $hints->{list}->(@results) ];
         }
+        elsif ( ref($hints->{list}) eq 'Regexp' ) {
+            $match = q[ grep $_ =~ $hints->{list}, @results ];
+        }
+        elsif ( !defined $hints->{list} ) {
+            $match = q[ grep !defined, @results ];
+        }
         elsif ( SMARTMATCH_ALLOWED ) {
             $match = q[ @results ~~ $hints->{list} ];
+            warnings::warnif('deprecated', sprintf(WARNING_SMARTMATCH_DEPRECATED, 'list', $sub));
+            if (SMARTMATCH_CATEGORY) {
+                $match = sprintf q[ do { no warnings '%s'; %s } ], SMARTMATCH_CATEGORY, $match;
+            }
         }
         else {
-            croak sprintf(ERROR_58_HINTS, 'list', $sub);
+            croak sprintf(ERROR_SMARTMATCH_HINTS, 'list', $sub);
         }
 
         $code .= qq{
@@ -1156,11 +1171,21 @@ sub _one_invocation {
             # works in 5.8.x, and always works in 5.10.1
             $match = q[ $hints->{scalar}->($retval) ];
         }
+        elsif ( ref($hints->{scalar}) eq 'Regexp' ) {
+            $match = q[ $retval =~ $hints->{scalar} ];
+        }
+        elsif ( !defined $hints->{scalar} ) {
+            $match = q[ !defined $retval ];
+        }
         elsif (SMARTMATCH_ALLOWED) {
             $match = q[ $retval ~~ $hints->{scalar} ];
+            warnings::warnif('deprecated', sprintf(WARNING_SMARTMATCH_DEPRECATED, 'scalar', $sub));
+            if (SMARTMATCH_CATEGORY) {
+                $match = sprintf q[ do { no warnings '%s'; %s } ], SMARTMATCH_CATEGORY, $match;
+            }
         }
         else {
-            croak sprintf(ERROR_58_HINTS, 'scalar', $sub);
+            croak sprintf(ERROR_SMARTMATCH_HINTS, 'scalar', $sub);
         }
 
         return $code . qq{

lib/autodie/exception.pm

@@ -14,8 +14,8 @@ our $DEBUG = 0;
 use overload
     q{""} => "stringify",
     # Overload smart-match only if we're using 5.10 or up
-    ($] >= 5.010 ? ('~~'  => "matches") : ()),
-    fallback => 1
+    (( $] >= 5.010 && $] < 5.041 ) ? ('~~'  => "matches") : ()),
+    fallback => 1,
 ;
 
 my $PACKAGE = __PACKAGE__;  # Useful to have a scalar for hash keys.

lib/autodie/hints.pm

@@ -101,10 +101,11 @@ return value of an autodying subroutine.  If the match returns true,
 C<autodie> considers the subroutine to have failed.
 
 If the hint provided is a subroutine, then C<autodie> will pass
-the complete return value to that subroutine.  If the hint is
-any other value, then C<autodie> will smart-match against the
-value provided.  In Perl 5.8.x there is no smart-match operator, and as such
-only subroutine hints are supported in these versions.
+the complete return value to that subroutine.  If the hint is a regexp object,
+then C<autodie> will match it against the return value. If the hint is undef,
+the return value must be undef. On Perl versions 5.10 and newer, any other
+value can be provided and it will be smart matched against the value provided.
+However, smart matched values like this are deprecated.
 
 Hints can be provided for both scalar and list contexts.  Note
 that an autodying subroutine will never see a void context, as

t/exceptions-smartmatch.t

@@ -1,18 +1,17 @@
 #!/usr/bin/perl -w
 use strict;
 use Test::More;
+use Fatal ();
 
-BEGIN { plan skip_all => "Perl 5.10 only tests" if $] < 5.010; }
+BEGIN { plan skip_all => "requires perl with smartmatch support" unless Fatal::SMARTMATCH_ALLOWED; }
 
-# These are tests that depend upon 5.10 (eg, smart-match).
+# These are tests that depend upon smartmatch.
 # Basic tests should go in basic_exceptions.t
 
 use 5.010;
 use warnings ();
 use constant NO_SUCH_FILE => 'this_file_had_better_not_exist_xyzzy';
-no if $] >= 5.017011, warnings => "experimental::smartmatch";
-no if exists $warnings::Offsets{"deprecated::smartmatch"},
-  warnings => "deprecated";
+no if Fatal::SMARTMATCH_CATEGORY, 'warnings', Fatal::SMARTMATCH_CATEGORY;
 
 plan 'no_plan';