Add better error message when == operator is badly used
Part of #40660.
With the following code:
```rust
fn foo<T: PartialEq>(a: &T, b: T) {
a == b;
}
fn main() {
foo(&1, 1);
}
```
It prints:
```
error[E0277]: the trait bound `&T: std::cmp::PartialEq<T>` is not satisfied
--> test.rs:2:5
|
2 | a == b;
| ^^^^^^ can't compare `&T` with `T`
|
= help: the trait `std::cmp::PartialEq<T>` is not implemented for `&T`
= help: consider adding a `where &T: std::cmp::PartialEq<T>` bound
error: aborting due to previous error
```
Ideally, we'd have the `Ty` inserted directly in the dep-node, but since
we can't do that yet, we extract the characteristic def-id of the type
in question.
Use the trait-environment+type as the key. Note that these
are only invoked on types that live for the entire compilation
(no inference artifacts). We no longer need the various special-case
bits and caches that were in place before.
`Vec::into_boxed_slice` and `[T]::into_vec` are inverses, so it makes sense
to mention the other in their respective documentation for visibility.
`Vec::into_boxed_slice` already mentions `[T]::into_vec`, but not the other
way around until now.
These files are licensed under a different license
than the rest of the codebase. This causes potential
issues and inconveniences.
Relicense these files under the standard license.
I hold original copyright on that code.
Fixes#36556
bootstrap: fix minor comment typos in lib.rs
I noticed these while reading through the build system
documentation. They're hardly worth fixing, but I'm also using this to
get my feet wet with the rustc contribution system.
I noticed these while reading through the build system
documentation. They're hardly worth fixing, but I'm also using this to
get my feet wet with the rustc contribution system.
Not being an enum improves ergonomics, especially since NonEmpty could be Empty. It can still be iterable without an extra "done" bit by making the range have !(start <= end), which is even possible without changing the Step trait.
Implements RFC 1980
Update rust-installer to normalize manifest paths
This fixes the backslash-paths found in the manifests of installers that are built on Windows. This is the most problematic part of #42121, leaving just the non-executable install.sh.
r? @alexcrichton
Improving std::env docs
Addresses #29351.
Hopefully this addresses the following points:
> - iterators should use the standard iterator boilerplate like https://doc.rust-lang.org/std/iter/struct.Map.html, this applies to all structs except for JoinPathsError
> - JoinPathsError should properly link the function it comes from and use language similar to https://doc.rust-lang.org/std/io/struct.Error.html
> - same wording issues with VarError
> - functions need to ensure linkage to things they refer to in their descriptions
> - Explain the difference between `os` and non-`os` structs and methods
expose needs_drop under mem
Note that I purposefully didn't update the intrinsic's documentation, because I think it makes sense for it be more... "honest" about its semantics.
