$ perl -wle'
if (1) {
  my $fh = "foo";
}
else {
  my $fh = "bar";
}
print $fh'
Name "main::fh" used only once: possible typo at -e line 8.
Use of uninitialized value in print at -e line 8.

$ perl -Mstrict -wle'
if (1) {
  my $fh = "foo";
}
else {
  my $fh = "bar";
}
print $fh'
Global symbol "$fh" requires explicit package name at -e line 8.
Execution of -e aborted due to compilation errors.