New errors: expected/found types omitted

[birkenfeld]

I found this when I wanted to see how the new errors look. (If this is still expected to be WIP, let me know and I won't report other such cases for a while.)

In this test case, the "expected/found" notes don't appear:

$ x86_64-unknown-linux-gnu/stage1/bin/rustc src/test/compile-fail/wrong-ret-type.rs
src/test/compile-fail/wrong-ret-type.rs:12:49: 12:50 error: mismatched types [E0308]
src/test/compile-fail/wrong-ret-type.rs:12 fn mk_int() -> usize { let i: isize = 3; return i; }
                                                                                           ^
src/test/compile-fail/wrong-ret-type.rs:12:49: 12:50 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to previous error

$ rustc src/test/compile-fail/wrong-ret-type.rs
src/test/compile-fail/wrong-ret-type.rs:12:49: 12:50 error: mismatched types:
 expected `usize`,
    found `isize` [E0308]
src/test/compile-fail/wrong-ret-type.rs:12 fn mk_int() -> usize { let i: isize = 3; return i; }
                                                                                           ^
src/test/compile-fail/wrong-ret-type.rs:12:49: 12:50 help: run `rustc --explain E0308` to see a detailed explanation
error: aborting due to previous error

[birkenfeld]

/cc @nikomatsakis

[birkenfeld]

Ah, I can see that this is because both types are "primitive", i.e. bool/char/int/float. In this case is_simple_error is true here and note_expected_found is not called.

Previously, for these cases the "inner type error" in parens was omitted - which appears to be omitted in all cases now. I think the is_simple_error can just be removed, I'll open a PR.

[nikomatsakis]

cc @jonathandturner