Thanks, the bug report shows that __LINE__ gets confused while parsing and compiling the code, which is not the fault of the debugger.

Of course a warn in the test script would have demonstrated the wrong __LINE__ too.

update

> Bisecting this was a bit tricky,

well, with help of the warn statements hinting to __LINE__, it would have been much easier.

update

turns out that the git on my win-box runs under v5.26, and it's easily demonstrated there:

$ perl -v

This is perl 5, version 26, subversion 2 (v5.26.2) built for x86_64-ms
+ys-thread-multi


$ perl
warn "before";
s(x)
(y);
warn "after";
__END__
before at - line 1.
after at - line 3.

$ perl
warn "before";
s/x/y/;
warn "after";
__END__
before at - line 1.
after at - line 3.

$ perl -MO=Concise
warn "before";
s(x)
(y);
warn "after";
__END__
d  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -:1) v:{ ->3
5     <@> warn[t1] vK/1 ->6
3        <0> pushmark s ->4
4        <$> const[PV "before"] s ->5
6     <;> nextstate(main 1 -:2) v:{ ->7
8     </> subst(/"x"/) vK ->9
7        <$> const[PV "y"] s ->8
9     <;> nextstate(main 1 -:3) v:{ ->a         # should be :4 not :3
c     <@> warn[t2] vK/1 ->d
a        <0> pushmark s ->b
b        <$> const[PV "after"] s ->c
- syntax OK
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