`?comptime_int` should coerce to optional non-comptime int

const T = struct {
    x: bool,
};

pub fn main() void {
    var val: ?usize = @typeInfo(T).Struct.fields[0].offset;
}

./asdf4.zig:6:52: error: expected type '?usize', found '?comptime_int'
    var val: ?usize = @typeInfo(T).Struct.fields[0].offset;
                                                   ^
./asdf4.zig:6:52: note: optional type child 'comptime_int' cannot cast into optional type child 'usize'
    var val: ?usize = @typeInfo(T).Struct.fields[0].offset;
                                                   ^

[s-ol]

This doesn't just affect comptime_int to other types, it seems to be a general limitation with optional types at the moment. For example:

    test "implicit cast optional numbers to any optional type the value fits" {
        const original: ?u8 = 123;
        var val: ?u32 = original;
        expect(val == 123);
    }

The error message here comes out especially strange, the last note is just plain wrong:

./test/stage1/behavior/cast.zig:576:21: error: expected type '?u32', found '?u8'
    var val: ?u32 = original;
                    ^
./test/stage1/behavior/cast.zig:576:21: note: optional type child 'u8' cannot cast into optional type child 'u32'
    var val: ?u32 = original;
                    ^
./test/stage1/behavior/cast.zig:576:21: note: unsigned 32-bit int cannot represent all possible unsigned 8-bit values
    var val: ?u32 = original;

EDIT: the same is true for error unions, anyerror!u8 cannot cast into anyerror!u32. It seems that the casting code in ir_analyze_cast needs to be generalized a bit to deal with these optional layers of nesting (error union of optional type of pointer of payload) more gracefully