This commit deletes the internal liblog in favor of the implementation that
lives on crates.io. Similarly it's also setting a convention for adding crates
to the compiler. The main restriction right now is that we want compiler
implementation details to be unreachable from normal Rust code (e.g. requires a
feature), and by default everything in the sysroot is reachable via `extern
crate`.
The proposal here is to require that crates pulled in have these lines in their
`src/lib.rs`:
#![cfg_attr(rustbuild, feature(staged_api, rustc_private))]
#![cfg_attr(rustbuild, unstable(feature = "rustc_private", issue = "27812"))]
This'll mean that by default they're not using these attributes but when
compiled as part of the compiler they do a few things:
* Mark themselves as entirely unstable via the `staged_api` feature and the
`#![unstable]` attribute.
* Allow usage of other unstable crates via `feature(rustc_private)` which is
required if the crate relies on any other crates to compile (other than std).
Uninhabited while-let pattern fix
This fix makes it so while-let with an unsatisfiable pattern raises a correct warning rather than an incorrect error.
Add warning for () to ! switch
With feature(never_type) enabled diverging type variables will default to `!` instead of `()`. This can cause breakages where a trait is resolved on such a type.
This PR emits a future-compatibility warning when it sees this happen.
This commit updates the version number to 1.17.0 as we're not on that version of
the nightly compiler, and at the same time this updates src/stage0.txt to
bootstrap from freshly minted beta compiler and beta Cargo.
Hide uninhabitedness checks behind feature gate
This reverts the fix to match exhaustiveness checking so that it can be discussed. The new code is now hidden behind the `never_type` feature gate.
exclusive range patterns
adds `..` patterns to the language under a feature gate (`exclusive_range_pattern`).
This allows turning
``` rust
match i {
0...9 => {},
10...19 => {},
20...29 => {},
_ => {}
}
```
into
``` rust
match i {
0..10 => {},
10..20 => {},
20..30 => {},
_ => {}
}
```
First issue here was the fact that we’d only allow negating integers in i64 range in case the
integer was not infered yes. While this is not the direct cause of the issue, its still good to fix
it.
The real issue here is the code handling specifically the `min_value` literals. While I128_OVERFLOW
has the expected value (0x8000_..._0000), match using this value as a pattern is handled
incorrectly by the stage1 compiler (it seems to be handled correctly, by the stage2 compiler). So
what we do here is extract this pattern into an explicit `==` until the next snapshot.
Fixes#38987
We now cache the inhabitedness of types in the GlobalCtxt.
Rather than calculating whether a type is visibly uninhabited from a given
NodeId we calculate the full set of NodeIds from which a type is visibly
uninhabited then cache that set. We can then use that to answer queries about
the inhabitedness of a type relative to any given node.
