never patterns: Check bindings wrt never patterns
Never patterns:
- Shouldn't contain bindings since they never match anything;
- Don't count when checking that or-patterns have consistent bindings.
r? `@compiler-errors`
Tune the inlinability of `unwrap`
Fixes#115463
cc `@thomcc`
This tweaks `unwrap` on ~~`Option` &~~ `Result` to be two parts:
- `#[inline(always)]` for checking the discriminant
- `#[cold]` for actually panicking
The idea here is that checking the discriminant on a `Result` ~~or `Option`~~ should always be trivial enough to be worth inlining, even in `opt-level=z`, especially compared to passing it to a function.
As seen in the issue and codegen test, this will hopefully help particularly for things like `.try_into().unwrap()`s that are actually infallible, but in a way that's only visible with the inlining.
EDIT: I've restricted this to `Result` to avoid combining effects
Use `zip_eq` to enforce that things being zipped have equal sizes
Some `zip`s are best enforced to be equal, since size mismatches suggest deeper bugs in the compiler.
Fix `allow_internal_unstable` for `(min_)specialization`
Fixes#119950
Blocked on #119949 (comment doesn't make sense until that merges)
I'd like to follow this up and look for more instances of not properly checking spans for features but I wanted to fix the motivating issue.
`OutputTypeParameterMismatch` -> `SignatureMismatch`
I'm probably missing something that made this rename more complicated. What did you end up getting stuck on when renaming this selection error, `@lcnr?`
**also** I renamed the `FulfillmentErrorCode` variants. This is just churn but I wanted to do it forever. I can move it out of this PR if desired.
r? lcnr
std: Doc blocking behavior of LazyLock
Adding notes about blocking behavior of calls that can block the current thread, similar to those on https://doc.rust-lang.org/std/sync/struct.OnceLock.html
I'm not sure if the "This method never blocks." counterparts would be desired. If so, can add those, as well.
Silence some follow-up errors [3/x]
this is one piece of the requested cleanups from https://github.com/rust-lang/rust/pull/117449
Keep error types around, even in obligations.
These help silence follow-up errors, as we now figure out that some types (most notably inference variables) are equal to an error type.
But it also allows figuring out more types in the presence of errors, possibly causing more errors.
coverage: Simplify building the coverage graph with `CoverageSuccessors`
This is a collection of simplifications to the code that builds the *basic coverage block* graph, which is a simplified view of the MIR control-flow graph that ignores panics and merges straight-line sequences of blocks into a single BCB node.
The biggest change is to how we determine the coverage-relevant successors of a block. Previously we would call `Terminator::successors` and apply some ad-hoc postprocessing, but with this PR we instead have our own `match` on the terminator kind that produces a coverage-specific enum `CoverageSuccessors`. That enum also includes information about whether a block has exactly one successor that it can be chained into as part of a single BCB.
Exhaustiveness: remove the need for arena-allocation within the algorithm
After https://github.com/rust-lang/rust/pull/119688, exhaustiveness checking doesn't need access to the arena anymore. This simplifies the lifetime story and makes it compile on stable without the extra dependency.
r? `@compiler-errors`
Inverting the condition lets us merge the two `Ok(false)` paths. I also
find the inverted condition easier to read: "all the things that must be
true for trimming to occur", instead of "any of the things that must be
true for trimming to not occur".
Later in this stack, as the nonzero_integers macro is going to be
responsible for producing a larger fraction of the API for the NonZero
integer types, it will need to receive a number of additional arguments
beyond the ones currently seen here.
Additional arguments, especially named arguments across multiple lines,
will turn out clearer if everything in one macro call is for the same
NonZero type.
This commit adopts a similar arrangement to what we do for generating
the API of the integer primitives (`impl u8` etc), which also generate a
single type's API per top-level macro call, rather than generating all
12 impl blocks for the 12 types from one macro call.
