+--- dereferencing ---
+
+$x # no warnings 'uninitialized'; my @a = %$x; () # ($strict ? qr/Can't use an undefined value as a HASH reference/ : ''), undef, undef
+$x # no warnings 'uninitialized'; my @a = %$x; () # ($strict ? qr/Can't use an undefined value as a HASH reference/ : ''), undef, undef #
+$x # no warnings 'uninitialized'; my @a = %$x; () # ($strict ? qr/Can't use an undefined value as a HASH reference/ : ''), undef, undef # +fetch
+$x # no warnings 'uninitialized'; my @a = %$x; () # ($strict ? qr/Can't use an undefined value as a HASH reference/ : ''), undef, undef # +exists
+$x # no warnings 'uninitialized'; my @a = %$x; () # ($strict ? qr/Can't use an undefined value as a HASH reference/ : ''), undef, undef # +delete
+$x # no warnings 'uninitialized'; my @a = %$x; () # ($strict ? qr/Can't use an undefined value as a HASH reference/ : ''), undef, undef # +store
+
+$x->{a} = 1 # my @a = %$x; () # '', undef, { a => 1 } # +fetch
+$x->{a} = 1 # my @a = %$x; () # '', undef, { a => 1 } # +exists
+$x->{a} = 1 # my @a = %$x; () # '', undef, { a => 1 } # +delete
+$x->{a} = 1 # my @a = %$x; () # '', undef, { a => 1 } # +store
+