fullPtrTypeComponents

fn fullPtrTypeComponents(tree: Ast, info: full.PtrType.Components) full.PtrType {
    const size: std.lang.Type.Pointer.Size = switch (tree.tokenTag(info.main_token)) {
        .asterisk => .one,
        .l_bracket => switch (tree.tokenTag(info.main_token + 1)) {
            .asterisk => if (tree.tokenTag(info.main_token + 2) == .identifier) .c else .many,
            else => .slice,
        },
        else => unreachable,
    };
    var result: full.PtrType = .{
        .size = size,
        .allowzero_token = null,
        .const_token = null,
        .volatile_token = null,
        .duplicate_token = null,
        .ast = info,
    };
    // We need to be careful that we don't iterate over any sub-expressions
    // here while looking for modifiers as that could result in false
    // positives. Therefore, start after a sentinel if there is one and
    // skip over any align node and bit range nodes.
    var i = (if (info.sentinel.unwrap()) |sentinel| tree.lastToken(sentinel) + 1 else switch (size) {
        .one => info.main_token,
        .slice => info.main_token + 1,
        .many => info.main_token + 2,
        .c => info.main_token + 3,
    }) + 1;
    const end = tree.firstToken(info.child_type);
    while (i < end) : (i += 1) {
        switch (tree.tokenTag(i)) {
            .keyword_allowzero => {
                if (result.allowzero_token != null) {
                    result.duplicate_token = i;
                }
                result.allowzero_token = i;
            },
            .keyword_const => {
                if (result.const_token != null) {
                    result.duplicate_token = i;
                }
                result.const_token = i;
            },
            .keyword_volatile => {
                if (result.volatile_token != null) {
                    result.duplicate_token = i;
                }
                result.volatile_token = i;
            },
            .keyword_align => {
                if (info.bit_range_end.unwrap()) |bit_range_end| {
                    assert(info.bit_range_start != .none);
                    i = tree.lastToken(bit_range_end) + 1;
                } else if (info.align_node.unwrap()) |align_node| {
                    i = tree.lastToken(align_node) + 1;
                } else unreachable;
            },
            .keyword_addrspace => i = tree.lastToken(info.addrspace_node.unwrap().?) + 1,
            else => unreachable,
        }
    }
    return result;
}