Replaced self-reflective explicit types with clearer `Self` or `Self::…` in stdlib docs
Many docs examples use explicit types instead of the semantically more clear `Self`/`Self::…` aliases.
By using the latter it's clear that the value's type depends on either `Self`, or an associated type of `Self`, instead of some constant type. It's also more consistent (and I'd argue correct), as the current docs aren't really consistent in this, as can be seen from the diff.
This is a best effort PR, as I was basically going through the docs manually, looking for offending examples. I'm sure I missed a few. Gotta start somewhere.
extra testing of how NLL handles wildcard type `_`
test that wildcard type `_` is not duplicated by `type Foo<X> = (X, X);` and potentially instantiated at different types when used in type ascriptions in let bindings.
(NLL's handling of this for the type ascription *expression form* is currently broken, or at least differs from what AST-borrowck does. I'll file a separate bug about that. Its not something critical to address since that expression is guarded by `#![feature(type_ascription)]`.)
cc #55748
Add todo!() macro
The primary use-case of `todo!()` macro is to be a much easier to type
alternative to `unimplemented!()` macro.
EDIT: hide unpopular proposal about re-purposing unimplemented
<details>
However, instead of just replacing `unimplemented!()`, it gives it a
more nuanced meaning: a thing which is intentionally left
unimplemented and which should not be called at runtime. Usually,
you'd like to prevent such cases statically, but sometimes you, for
example, have to implement a trait only some methods of which are
applicable. There are examples in the wild of code doing this thing,
and in this case, the current message of `unimplemented`, "not *yet*
implemented" is slightly misleading.
With the addition of TODO, you have three nuanced choices for a
`!`-returning macro (in addition to a good-old panic we all love):
* todo!()
* unreachable!()
* unimplemented!()
Here's a rough guideline what each one means:
- `todo`: use it during development, as a "hole" or placeholder. It
might be a good idea to add a pre-commit hook which checks that
`todo` is not accidentally committed.
- `unreachable!()`: use it when your code can statically guarantee
that some situation can not happen. If you use a library and hit
`unreachable!()` in the library's code, it's definitely a bug in the
library. It's OK to have `unreachable!()` in the code base,
although, if possible, it's better to replace it with
compiler-verified exhaustive checks.
- `unimplemented!()`: use it when the type checker forces you to
handle some situation, but there's a contract that a callee must not
actually call the code. If you use a library and hit
`unimplemented!()`, it's probably a bug in your code, though
it *could* be a bug in the library (or library docs) as well. It is
ok-ish to see an `unimplemented!()` in real code, but it usually
signifies a clunky, eyebrow-rising API.
</details>
overhaul intra-doc-link ambiguity warning
Fixes#52784.
- Makes the warning part of the `intra_doc_link_resolution_failure`
lint.
- Tightens the span to just the ambiguous link.
- Reports ambiguities across all three namespaces.
- Uses structured suggestions for disambiguation.
- Adds a test for the warnings.
r? @QuietMisdreavus
Filter ui revision tests
Updates UI test output filtering to also filter away test annotations for revisions:
Previously filtered: //~ ERROR [XXXX]
Now also filters: //[revision]~ ERROR [XXXX]
I reckon, if we have the one, we should have the other for consistency, its lack was probably an oversight (the existence of revision testing is not really well documented...)
Revert the `LazyConst` PR
The introduction of `LazyConst` did not actually achieve the code simplicity improvements that were the main reason it was introduced. Especially in the presence of const generics, the differences between the "levels of evaluatedness" of a constant become less clear. As it can be seen by the changes in this PR, further simplifications were possible by folding `LazyConst` back into `ConstValue`. We have been able to keep all the advantages gained during the `LazyConst` refactoring (like `const_eval` not returning an interned value, thus making all the `match` code simpler and more performant).
fixes https://github.com/rust-lang/rust/issues/59209
r? @eddyb @varkor
Option and Result: Add references to documentation of as_ref and as_mut
This makes the documentation more consistent with that of `Pin::as_ref` which converts "from `&Pin<Pointer<T>>` to `Pin<&t>`".
This generally makes it clearer that the reference is going inside the option.
Remove restriction on isize/usize in repr(simd)
As discussed in #55078, there's no known reason for this restriction.
It's unlikely that repr(simd) will be stabilized in its current form, but
might as well remove some restrictions on it.
This removes the branch in `is_machine` which returns false for these types.
`is_machine` is only used for the repr(simd) type validation check.
No old chestnuts in iter::repeat docs
The current language may be amusing, yet is just imprecise and most especially difficult to understand for someone who speaks English as a foreign language.
