Confusing `not trait` error message

[klutzy]

use t::T;
mod t {
    pub trait T {}
}

struct S;

impl T for S {}

impl T {} // oops

fn main() {}

a.rs:8:5: 8:6 error: T is not a trait
a.rs:8 impl T for S {}
            ^

This should show better error message. If trait T is not in mod, rustc prints "duplicate definition of module T".

[klutzy]

If S is completely omitted, rustc prints found value name used as a type: DefMod(syntax::ast::DefId{crate: 0, node: 10}). This also looks bad.

[jdm]

That's covered in #8767.

[steveklabnik]

Just tried this out, the error is identical today.

[steveklabnik]

This error is much better:

hello.rs:10:1: 10:10 error: inherent implementations are only allowed on types defined in the current module [E0257]
hello.rs:10 impl T {} // oops
            ^~~~~~~~~
hello.rs:1:5: 1:9 note: import from other module here
hello.rs:1 use t::T;
               ^~~~

I'm going to consider this one closed.