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Tracking uninhabited types in matches #51076
Description
I think there has been a regression for the treatment of uninhabited types at some point:
#![feature(never_type)]
fn foo() -> Result<(), !> {
return Ok(());
}
fn main() {
match foo() {
Ok(_) => println!("yay!")
}
}now fails with:
error[E0004]: non-exhaustive patterns: `Err(_)` not covered
--> src/main.rs:7:11
|
7 | match foo() {
| ^^^^^ pattern `Err(_)` not covered
I will bisect and report back when I find the commit which caused the regression.
Last known to work on:
- nightly-2018-03-15
Was already failing on:
- nightly-2018-04-01
Activity
Victor-Savu commentedon May 26, 2018
Turns out the "problem" was introduced in #47630 which attempted to stabilize
never_typeand leave only this particular case under theexhaustive_patternsfeature gate. When that PR was subsequently reverted in #49691, the split in feature gates was not reverted, so now the code above needs both features:I think this issue is not really relevant anymore, but I am afraid that this could be confusing. I look forward to the stabilization of both features, when all of this will go away :)