>perl -wMstrict -le
"print F();
 { my $y = X();    sub F { return $y } }
 { my $x = 'foo';  sub X { return $x } }
"
Use of uninitialized value in print at -e line 1.


>perl -wMstrict -le
"print F();
 BEGIN { my $y = X();    sub F { return $y } }
 BEGIN { my $x = 'foo';  sub X { return $x } }
"
Undefined subroutine &main::X called at -e line 1.
BEGIN failed--compilation aborted at -e line 1.

>perl -wMstrict -le
"print F();
 BEGIN { my $x = 'foo';  sub X { return $x } }
 BEGIN { my $y = X();    sub F { return $y } }
"
foo

>perl -wMstrict -le
"print F();
 INIT { my $y = X();    sub F { return $y } }
 INIT { my $x = 'foo';  sub X { return $x } }
"
Use of uninitialized value in print at -e line 1.


>perl -wMstrict -le
"print F();
 INIT { my $x = 'foo';  sub X { return $x } }
 INIT { my $y = X();    sub F { return $y } }
"
foo