librustc: hint close matches on accessing nonexisting fields

[oli-obk]

struct A {
    foo : int,
    car : int,
    barr : int
}
fn main() {
    let a = A { foo : 5, car : 9, bar : 42};
}

now shows

main.rs:7:39: 7:42 error: structure `A` has no field named `bar`
main.rs:7     let a = A { foo : 5, car : 9, bar : 42};
                                            ^~~
main.rs:7:39: 7:42 help: did you mean `car`?
main.rs:7     let a = A { foo : 5, car : 9, bar : 42};
                                            ^~~
main.rs:7:39: 7:42 help: did you mean `barr`?
main.rs:7     let a = A { foo : 5, car : 9, bar : 42};
                                            ^~~

same help message for accessing fields.

can't do it for functions, as they aren't iteratable. Only exact lookups are possible there.

[emberian]

Our style is to not add any whitespace for alignment.

[emberian]

Could you add some tests for this? Just a few cases in compile-fail that the messages get emitted.

[Gankra]

@oli-obk have you made all your changes? (github doesn't notify us when you just add commits, you need to ping someone when you're ready).

Regardless, needs a rebase.

[oli-obk]

not yet, as i need to rewrite some of the error reporting code, to prevent hinting field names of fields that are actually set

[flaper87]

closing for inactivity. @oli-obk let us know when you get back to this. It needs rebase so probably a new PR would be just fine.