+--- aliasing ---
+
+$x # 1 for $x->{a}; () # '', undef, { a => undef }
+$x # 1 for $x->{a}; () # '', undef, { a => undef } #
+$x # 1 for $x->{a}; () # '', undef, { a => undef } # +fetch
+$x # 1 for $x->{a}; () # '', undef, { a => undef } # +exists
+$x # 1 for $x->{a}; () # '', undef, { a => undef } # +delete
+$x # 1 for $x->{a}; () # qr/^Can't vivify reference/, undef, undef # +store
+
+$x # $_ = 1 for $x->{a}; () # '', undef, { a => 1 }
+$x # $_ = 1 for $x->{a}; () # '', undef, { a => 1 } #
+$x # $_ = 1 for $x->{a}; () # '', undef, { a => 1 } # +fetch
+$x # $_ = 1 for $x->{a}; () # '', undef, { a => 1 } # +exists
+$x # $_ = 1 for $x->{a}; () # '', undef, { a => 1 } # +delete
+$x # $_ = 1 for $x->{a}; () # qr/^Can't vivify reference/, undef, undef # +store
+
+$x->{a} = 1 # 1 for $x->{a}; () # '', undef, { a => 1 } # +fetch
+$x->{a} = 1 # 1 for $x->{b}; () # '', undef, { a => 1, b => undef } # +fetch
+$x->{a} = 1 # 1 for $x->{a}; () # '', undef, { a => 1 } # +exists
+$x->{a} = 1 # 1 for $x->{b}; () # '', undef, { a => 1, b => undef } # +exists
+$x->{a} = 1 # 1 for $x->{a}; () # '', undef, { a => 1 } # +delete
+$x->{a} = 1 # 1 for $x->{b}; () # '', undef, { a => 1, b => undef } # +delete
+$x->{a} = 1 # 1 for $x->{a}; () # '', undef, { a => 1 } # +store
+$x->{a} = 1 # 1 for $x->{b}; () # '', undef, { a => 1, b => undef } # +store
+
+$x # do_nothing($x->{a}); () # '', undef, { }
+$x # do_nothing($x->{a}); () # '', undef, { } #
+$x # do_nothing($x->{a}); () # '', undef, { } # +fetch
+$x # do_nothing($x->{a}); () # '', undef, { } # +exists
+$x # do_nothing($x->{a}); () # '', undef, { } # +delete
+$x # do_nothing($x->{a}); () # qr/^Can't vivify reference/, undef, undef # +store
+
+$x # set_arg($x->{a}); () # '', undef, { a => 1 }
+$x # set_arg($x->{a}); () # '', undef, { a => 1 } #
+$x # set_arg($x->{a}); () # '', undef, { a => 1 } # +fetch
+$x # set_arg($x->{a}); () # '', undef, { a => 1 } # +exists
+$x # set_arg($x->{a}); () # '', undef, { a => 1 } # +delete
+$x # set_arg($x->{a}); () # qr/^Can't vivify reference/, undef, undef # +store
+
+--- dereferencing ---
+
+$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 = %$x; () # '', undef, { a => 1 } # +store
+
+--- slice ---
+
+$x # my @a = @$x{'a', 'b'}; \@a # '', [ undef, undef ], { }
+$x # my @a = @$x{'a', 'b'}; \@a # '', [ undef, undef ], undef #
+$x # my @a = @$x{'a', 'b'}; \@a # '', [ undef, undef ], undef # +fetch
+$x # my @a = @$x{'a', 'b'}; \@a # '', [ undef, undef ], { } # +exists
+$x # my @a = @$x{'a', 'b'}; \@a # '', [ undef, undef ], { } # +delete
+$x # my @a = @$x{'a', 'b'}; \@a # '', [ undef, undef ], { } # +store
+
+$x->{b} = 0 # my @a = @$x{'a', 'b'}; \@a # '', [ undef, 0 ], { b => 0 } # +fetch
+
+$x # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 }
+$x # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 } #
+$x # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 } # +fetch
+$x # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 } # +exists
+$x # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 } # +delete
+$x # @$x{'a', 'b'} = (1, 2); () # qr/^Can't vivify reference/, undef, undef # +store
+
+$x->{a} = 0 # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 } # +store
+$x->{c} = 0 # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2, c => 0 } # +store
+$x->{a} = 0, $x->{b} = 0 # @$x{'a', 'b'} = (1, 2); () # '', undef, { a => 1, b => 2 } # +store
+