Tweak errors for missing associated types and type parameters
* On `dyn Trait` missing associated types, provide a structured suggestion for them
* On missing type parameters, provide structured suggestion for them
* Point at trait definition when missing required type parameter
* Tweak output of E0658
* Tweak wording of E0719
* Account for `Trait1 + Trait2` case
Fix#66380, fix#60595. CC #63711.
Deprecate Error::description for real
`description` has been documented as soft-deprecated since 1.27.0 (17 months ago). There is no longer any reason to call it or implement it.
This PR:
- adds `#[rustc_deprecated(since = "1.41.0")]` to `Error::description`;
- moves `description` (and `cause`, which is also deprecated) below the `source` and `backtrace` methods in the Error trait;
- reduces documentation of `description` and `cause` to take up much less vertical real estate in rustdocs, while preserving the example that shows how to render errors without needing to call `description`;
- removes the description function of all *currently unstable* Error impls in the standard library;
- marks `#[allow(deprecated)]` the description function of all *stable* Error impls in the standard library;
- replaces miscellaneous uses of `description` in example code and the compiler.
---
The callbacks have precisely two states: the default, and the one
present throughout almost all of the rustc run (the filled in value
which has access to TyCtxt).
We used to store this as a thread local, and reset it on each thread to
the non-default value. But this is somewhat wasteful, since there is no
reason to set it globally -- while the callbacks themselves access TLS,
they do not do so in a manner that fails in when we do not have TLS to
work with.
Generalize `array_into_iter` lint to also lint for boxed arrays
`Box` is special in that a method call on a box can move the value out
of the box. Thus, the same backwards-compatibility problem can arise
for boxed arrays as for simple arrays.
---
CC #66145
r? @matthewjasper (as you reviewed the first PR)
`description` has been documented as soft-deprecated since 1.27.0 (17
months ago). There is no longer any reason to call it or implement it.
This commit:
- adds #[rustc_deprecated(since = "1.41.0")] to Error::description;
- moves description (and cause, which is also deprecated) below the
source and backtrace methods in the Error trait;
- reduces documentation of description and cause to take up much less
vertical real estate in rustdocs, while preserving the example that
shows how to render errors without needing to call description;
- removes the description function of all *currently unstable* Error
impls in the standard library;
- marks #[allow(deprecated)] the description function of all *stable*
Error impls in the standard library;
- replaces miscellaneous uses of description in example code and the
compiler.
This still doesn't handle the case entirely correctly, requiring a more
targeted approach with a better suggestion, but at least now the
suggested syntax makes *some* sense.
(Mostly) finish formatting the repository
Silences tidy line length warnings on rustfmt-controlled files.
This leaves two things out of formatting: CloudABI (mostly because it's not really ours to control, it's upstream code that's mostly generated), and tests. The latter is a hard problem and maybe not one to worry too much about, we rarely edit old tests and reformatting them as we go if possible isn't too bad (they're generally small).
