$ perl -e'use Devel::LeakTrace::Fast; { my $x = []; }'
leaked SV(0x0x814ec28) from -e line 1
leaked SV(0x0x814ed84) from -e line 1

$ perl -e'use Devel::LeakTrace::Fast; { my $x = []; 1; }'

$ perl -e'use Devel::LeakTrace::Fast; { my $x = []; } 1;'

$
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I suspect the value to which the sassign (=) evaluates (the reference returned by []) is on the stack for some unknown reason. As show, it doesn't stay there if you add *anything* to the program. So not a leak. For example, the only difference in the above "leaking" and fine code is an op used to give line numbers to warnings.

$ diff -u \
>    <( perl -MO=Concise,-exec -we'use Devel::LeakTrace::Fast; { my $x
+ = []; }  ' 2>&1 ) \
>    <( perl -MO=Concise,-exec -we'use Devel::LeakTrace::Fast; { my $x
+ = []; } 1' 2>&1 )
--- /dev/fd/63  2009-04-21 15:31:32.471371429 -0400
+++ /dev/fd/62  2009-04-21 15:31:32.475372857 -0400
@@ -9,4 +9,5 @@
 8  <0> padsv[$x:279,280] sRM*/LVINTRO
 9  <2> sassign vKS/2
 a  <2> leaveloop vK/2
+b  <;> nextstate(main 281 -e:1) v        <-- only difference
-b  <@> leave[1 ref] vKP/REFC
+c  <@> leave[1 ref] vKP/REFC
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Oddly, I can't reproduce it using

$ perl -e'use Devel::LeakTrace::Fast; { my $x = []; $x }'

$
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The two values being "leaked", incidentally, must be the reference and the array being referenced.

Devel::Leak doesn't show any leaks

C:\>perl -MDevel::Leak -le"print Devel::Leak::NoteSV($handle); { my $x
+ = []; } print Devel::Leak::CheckSV($handle);"
5513
5513

C:\>perl -MO=Concise -e" { my $x = []; }
a  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 3 -e:1) v ->3
9     <2> leaveloop vK/2 ->a
3        <{> enterloop(next->9 last->9 redo->4) v ->4
-        <@> lineseq vK ->9
4           <;> nextstate(main 1 -e:1) v ->5
8           <2> sassign vKS/2 ->9
6              <@> anonlist sK* ->7
5                 <0> pushmark s ->6
7              <0> padsv[$x:1,2] sRM*/LVINTRO ->8
-e syntax OK

C:\>perl -MO=Concise -e" { my $x = []; 1}
b  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 3 -e:1) v ->3
a     <2> leaveloop vK/2 ->b
3        <{> enterloop(next->a last->a redo->4) v ->4
-        <@> lineseq vKP ->a
4           <;> nextstate(main 1 -e:1) v ->5
8           <2> sassign vKS/2 ->9
6              <@> anonlist sK* ->7
5                 <0> pushmark s ->6
7              <0> padsv[$x:1,2] sRM*/LVINTRO ->8
9           <;> nextstate(main 2 -e:1) v ->a
-           <0> ex-const v ->-
-e syntax OK

C:\>pmvers Devel::Leak
0.03

C:\>perl -v|grep buil
This is perl, v5.8.9 built for MSWin32-x86-multi-thread
Binary build 825 [288577] provided by ActiveState http://www.ActiveSta
+te.com
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