Incorrect handling of unbound virtual modifiers in key types

[mahkoh]

Consider the following map:

xkb_keymap {
    xkb_keycodes {
        <a> = 38;
        <leftshift> = 50;
    };
    xkb_types {
        virtual_modifiers Bound = Shift, Unbound;

        type "X" {
            modifiers = Bound+Unbound;
            map[Bound+Unbound] = Level1;
            map[Bound] = Level2;
        };
    };
    xkb_compat { };
    xkb_symbols {
        key <a> {
            type = "X",
            [ a, A ]
        };
        key <leftshift> {
            [ SetMods(mods = Shift) ]
        };
    };
};

The specification requires that

Map entries which specify unbound virtual modifiers (see Inactive Modifier Definitions) are not considered
[...]
When it is essential to distinguish between OneThing and Another, XKB considers only those modifier definitions for which all virtual modifiers are bound.

Since Unbound is not bound, the line

            map[Bound+Unbound] = Level1;

should be ignored.

But xkbcommon does not ignore it and maps Shift+a to Level1.

[wismill]

Good catch! Although with #450 landing soon, this will work as expected. So we should just wait for #450 to fix it.