‘Subroutine "&x" is not available’ during compilation

‘Subroutine "&x" is not available’ during compilation

sub {
  my $x;
  sub { eval '$x' }
}->()()
__END__
Variable "$x" is not available at (eval 1) line 2.

That one’s OK (though I wonder about the line number).

sub {
  my sub x {};
  sub { eval '\&x' }
}->()()
__END__
Variable "&x" is not available at (eval 1) line 1.

That should say ‘Subroutine’.