Match checking doesn't handle static constants correctly.

[eddyb]

I would guess it doesn't go (properly) through const eval, causing weird errors like this one:

static MAX: uint = -1;
match 0 {
    1u..MAX => {}, // error: mismatched types in range
    _ => {}
}

If the value of MAX is changed to -1u, the code compiles, showing that match checking looks at the value of the static MAX but not at its type or computed value.

Further experimentation - using -1 as uint for MAX - produces this ICE:

error: internal compiler error: node_id_to_type: no type for node `expr -1 as uint (id=26)`

[eddyb]

The ICE seems to have been fixed without mentioning this issue.
However, the original problem (with the initializer having a different type from the static itself) remains.

[pnkfelix]

cc #23897

[pnkfelix]

@eddyb I cannot reproduce the issue now; i.e. when I try (e.g. by plugging in mismatched types for the initializer, and also experimenting with using const vs static to see if that tickles something), I seem to consistently get a type check error.

can you make another example at this point demonstrating the issue here?

[pnkfelix]

e.g. here is one version of updated code, but it compiles and runs (playpen):

#![feature(negate_unsigned)]

fn main() {
    const MAX: usize = -1;
    match 0 {
        1usize...MAX => {},
        _ => {}
    }
}

[eddyb]

@pnkfelix it must have been fixed by adding more type information to const_eval, I guess.

[pnkfelix]

closing, assumed fixed