Using Carp::confess solves that and gives an accurate picture:

wrong number of arguments for baz(); has to be even at - line 12
    Foo::baz('one', 'uno', 'two', 'dos', 'three') called at - line 8
    Foo::bar() called at - line 2
[download]

...except where it doesn't ;-) - there are edge cases where Carp fails to backtrace properly.