errlanes 0.16.4

Four error lanes (Rejected/Denied/Transient/Fatal) carried in the type, not re-derived at every layer
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28

//! Compiles `upstream`/`downstream` (a dev-dependency of this crate) so the
//! six `?`-widening paths and the narrowed match from Appendix A
//! of the error-handling research doc are checked on every `cargo test`, and
//! pins that the generic widening from Option C (`impl From<Fail<A>> for
//! Fail<B>` in a downstream crate) does not compile.

#[test]
fn downstream_exercises_every_widening_path() {
    downstream::smoke();
}

#[test]
fn from_fail_a_for_fail_b_downstream_is_e0117() {
    let t = trybuild::TestCases::new();
    t.compile_fail("tests/coherence/e0117.rs");
}

/// Appendix B of the foreign-error interop design doc, pinned here rather
/// than in `errlanes-derive`'s trybuild suite because these cases exercise
/// the core traits and blanket impls directly, independent of any derive.
#[test]
fn classify_appendix_b_negative_cases() {
    let t = trybuild::TestCases::new();
    t.compile_fail("tests/coherence/classify_u1_rejection_into_fault.rs");
    t.compile_fail("tests/coherence/classify_u2_mixed_wrapper_into_fault.rs");
    t.compile_fail("tests/coherence/classify_u4_rejection_and_classify_conflict.rs");
    t.compile_fail("tests/coherence/classify_n_mixed_wrapper_into_bare_fatal.rs");
}