Ah, I see what you mean. You're wrong about it dying, though. It's only warning.

I don't find it unusual since I've previously heard that { $a cmp $b }, { $a <=> $b }, { $b cmp $a } and { $b <=> $a } are handled specially to avoid having to call a Perl sub repeatedly. 

>perl -MO=Concise -e"@a = sort { $a <=> $b } @a"
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 2 -e:1) v ->3
-     <1> ex-aassign vKS/64 ->8
-        <1> ex-list lK ->-
3           <0> pushmark s ->4
7           <@> sort lK/INPLACE,NUM ->8
4              <0> pushmark s ->5
6              <1> rv2av[t7] lKRM*/1 ->7
5                 <#> gv[*a] s ->6
-        <1> ex-list lK ->-
-           <0> ex-pushmark s ->-
-           <1> ex-rv2av lKRM*/1 ->-
-              <0> ex-gv s ->-
-e syntax OK

>perl -MO=Concise -e"@a = sort { 1; $a <=> $b } @a"
8  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 2 -e:1) v ->3
-     <1> ex-aassign vKS/64 ->8
-        <1> ex-list lK ->-
3           <0> pushmark s ->4
7           <@> sort lKS*/INPLACE ->8
4              <0> pushmark s ->5
-              <1> null sK/1 ->5
-                 <1> ex-leave sKP ->-
-                    <0> enter s ->-
-                    <;> nextstate(main 1 -e:1) v ->-
-                    <0> ex-const v ->-
-                    <;> nextstate(main 1 -e:1) v ->-
-                    <2> ncmp[t5] sK/2 ->(end)
-                       <1> ex-rv2sv sK/1 ->-
-                          <#> gvsv[*a] s ->-
-                       <1> ex-rv2sv sK/1 ->-
-                          <#> gvsv[*b] s ->-
6              <1> rv2av[t7] lKRM*/1 ->7
5                 <#> gv[*a] s ->6
-        <1> ex-list lK ->-
-           <0> ex-pushmark s ->-
-           <1> ex-rv2av lKRM*/1 ->-
-              <0> ex-gv s ->-
-e syntax OK

[download]

While I don't find it unusual, I do think the difference in behaviour is a bug.

In reply to Re^5: Dangerous Names by ikegami
in thread Dangerous Names by samtregar

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