Negative literals cast to unsigned integers without a warning.

[mahkoh]

let i: u8 = -1

Replacing -1 by 256 gives the following warning:

 literal out of range for its type

This could also apply to the code above. Unfortunately even an explicit cast to u8 doesn't remove the second warning.

Note that clang has a related warning:

warning: implicit conversion changes signedness: 'int' to 'unsigned int' [-Wsign-conversion]
        unsigned int i = -1;
                     ~   ^~

[Gankra]

Duplicate of #5477

[mahkoh]

not warning on this is a feature

So so.