[perl #90030] sort with no arguments

This eliminates the error ‘sort is now a reserved word’, which was
added for the sake of code that does close(sort) at about the time
that sort became a keyword.

As Tom Christiansen pointed out, it has been long enough.

This error only occurred with ) or ; after the keyword.  In other
cases with no arguments, like {sort} and (sort,0), it was treated as
an empty list.

So this commit makes it follow that.

Since the tests triggered it, this commit also fixes a crash caused by
commit 540dd770, which, when seeing whether it can optimise something
like ‘@a = sort @a’, assumes that there is something after the sort,
and crashes when there isn’t, as in {@a = sort}.

1 files changed, 12 insertions, 1 deletions

diff --git a/t/op/sort.t b/t/op/sort.t
index 2ab0cf5305..df1113b5ce 100644
--- a/t/op/sort.t
+++ b/t/op/sort.t
@@ -6,7 +6,7 @@ BEGIN {
     require 'test.pl';
 }
 use warnings;
-plan( tests => 165 );
+plan( tests => 171 );
 
 # these shouldn't hang
 {
@@ -949,3 +949,14 @@ is join("", sort hopefullynonexistent split//, '04381091'), '98431100',
 my $stubref = \&givemeastub;
 is join("", sort $stubref split//, '04381091'), '98431100',
     'AUTOLOAD with stubref';
+
+# [perl #90030] sort without arguments
+#eval '@x = (sort); 1';
+is $@, '', '(sort) does not die';
+is @x, 0, '(sort) returns empty list';
+#eval '@x = sort; 1';
+is $@, '', 'sort; does not die';
+is @x, 0, 'sort; returns empty list';
+eval '{@x = sort} 1';
+is $@, '', '{sort} does not die';
+is @x, 0, '{sort} returns empty list';