syntax: Treat error literals in more principled way
Free them from their character literal origins.
I actually tried to remove `LitKind::Err` entirely (by converting it into `ExprKind::Err` immediately), and it caused no diagnostic regressions in the test suite.
However, I'd still want to use error literals as general purpose error tokens some day, so I kept them.
The downside of having `LitKind::Err` in addition to `ExprKind::Err` is that every time you want to do something with `ExprKind::Err` you need to make sure that `ExprKind::Lit(LitKind::Err)` is treated in the same way.
Fortunately, this usually happens automatically because both literals and errors are "leaf" expressions, however this PR does fix a couple of inconsistencies between them.
Addresses https://github.com/rust-lang/rust/pull/60679#discussion_r282640663 in a way
[const-prop] Support Rvalue::{Ref,Len} and Deref
Also fixes an ICE I found in testing.
r? @oli-obk
~~The final commit is just for a perf run. I'll remove it after that is completed.~~
Remove asterisk suggestion for move errors in borrowck
As per the decision in #54985 completely removes the suggestion to add an asterisk when checking move errors. I believe I've preserved the correct behavior with the "consider borrowing here" branch of the original match arm, but I'm not positive on that.
This is my first PR to rustc so any feedback is greatly appreciated. Thanks.
Implementation of RFC 2289 (associated_type_bounds)
This PR implements the [`asociated_type_bounds` feature](https://github.com/rust-lang/rfcs/blob/master/text/2289-associated-type-bounds.md).
Associated type bounds are implemented in:
- function/method arguments and return types
- structs, enums, unions
- associated items in traits
- type aliases
- type parameter defaults
- trait objects
- let bindings
CC @nikomatsakis @centril
Fix NLL typeck ICEs
* Don't ICE when a type containing a region is constrained by nothing
* Don't ICE trying to normalize a type in a `ParamEnv` containing global bounds.
To explain what was happening in the `issue-61311-normalize.rs` case:
* When borrow checking the `the_fn` in the last `impl` we would try to normalize `Self::Proj` (`<Unit as HasProjFn>::Proj`).
* We would find the `impl` that we're checking and and check its `where` clause.
* This would need us to check `<Box<dyn Obj + 'static> as HasProj>::Proj: Bound`
* We find two possible implementations, the blanket impl and the bound in our `ParamEnv`.
* The bound in our `ParamEnv` was canonicalized, so we don't see it as a global bound. As such we prefer it to the `impl`.
* This means that we cannot normalize `<Box<dyn Obj + 'static> as HasProj>::Proj` to `Unit`.
* The `<Box<dyn Obj + 'static> as HasProj>::Proj: Bound` bound, which looks like it should be in our `ParamEnv` has been normalized to `Unit: Bound`.
* We fail to prove `<Box<dyn Obj + 'static> as HasProj>::Proj: Bound`.
* We ICE, since we believe typeck have errored.
Closes#61311Closes#61315Closes#61320
r? @pnkfelix
cc @nikomatsakis
As per issue #54985 removes the not useful suggestion to remove asterisk in
move errors. Includes minor changes to tests in the `ui` suite to account
for the removed suggestion.
Make cannot move errors more consistent with other borrowck errors
* Note the type of the place being moved in all cases.
* Note the place being moved from.
* Simplify the search for overloaded place operators
* Extend the note for move from overloaded deref apply to all types.
* Add a note for moves from overloaded index.
* Special case moves for closure captures.
r? @pnkfelix
Re-implement async fn drop order lowering
This PR re-implements the async fn drop order lowering changes so
that it all takes place in HIR lowering, building atop the work done by
@eddyb to refactor `Res::Upvar`.
Previously, this types involved in the lowering were constructed in
libsyntax as they had to be used during name resolution and HIR
lowering. This was awful because none of that logic should have existed
in libsyntax.
This commit also changes `ArgSource` to keep a `HirId` to the original
argument pattern rather than a cloned copy of the pattern.
Only b7aa4ed and 71fb8fa should be reviewed, any other commits
are from #61276 (though 447e336 might end up staying in this PR).
As a nice side effect, it also fixes#61187 (cc #61192).
r? @eddyb
cc @cramertj
add support for unchecked math
add compiler support for
```rust
/// Returns the result of an unchecked addition, resulting in
/// undefined behavior when `x + y > T::max_value()` or `x + y < T::min_value()`.
pub fn unchecked_add<T>(x: T, y: T) -> T;
/// Returns the result of an unchecked substraction, resulting in
/// undefined behavior when `x - y > T::max_value()` or `x - y < T::min_value()`.
pub fn unchecked_sub<T>(x: T, y: T) -> T;
/// Returns the result of an unchecked multiplication, resulting in
/// undefined behavior when `x * y > T::max_value()` or `x * y < T::min_value()`.
pub fn unchecked_mul<T>(x: T, y: T) -> T;
```
cc https://github.com/rust-lang/rfcs/issues/2508
