miri: improve and simplify overflow detection
This simplifies the overflow detection for signed binary operators, and adds overflow detection to unary operators so that const-prop doesn't have to crudely hand-roll that.
It also fixes some bugs in the operator implementation that however, I think, were not observable.
r? @oli-obk @wesleywiser
Improve reporting errors and suggestions for trait bounds
Fix#66802
- When printing errors for unsized function parameter, properly point at the parameter instead of function's body.
- Improve `consider further restricting this bound` (and related) messages by separating human-oriented hints from the machine-oriented ones.
When suggesting associated fn with type parameters, include in the structured suggestion
Address #50734.
```
error[E0046]: not all trait items implemented, missing: `foo`, `bar`, `baz`
--> file.rs:14:1
|
14 | impl TraitA<()> for S {
| ^^^^^^^^^^^^^^^^^^^^^ missing `foo`, `bar`, `baz` in implementation
|
= help: implement the missing item: `fn foo<T>(_: T) -> Self where T: TraitB, TraitB::Item = A { unimplemented!() }`
= help: implement the missing item: `fn bar<T>(_: T) -> Self { unimplemented!() }`
= help: implement the missing item: `fn baz<T>(_: T) -> Self where T: TraitB, <T as TraitB>::Item: std::marker::Copy { unimplemented!() }`
```
It doesn't work well for associated types with `ty::Predicate::Projection`s as we need to resugar `T: Trait, Trait::Assoc = K` → `T: Trait<Assoc = K>`.
Initial implementation of `#![feature(move_ref_pattern)]`
Following up on #45600, under the gate `#![feature(move_ref_pattern)]`, `(ref x, mut y)` is allowed subject to restrictions necessary for soundness. The match checking implementation and tests for `#![feature(bindings_after_at)]` is also adjusted as necessary.
Closes#45600.
Tracking issue: #68354.
r? @matthewjasper
Towards unified `fn` grammar
Part of https://github.com/rust-lang/rust/pull/68728.
- Syntactically, `fn` items in `extern { ... }` blocks can now have bodies (`fn foo() { ... }` as opposed to `fn foo();`). As above, we use semantic restrictions instead.
- Syntactically, `fn` items in free contexts (directly in a file or a module) can now be without bodies (`fn foo();` as opposed to `fn foo() { ... }`. As above, we use semantic restrictions instead, including for non-ident parameter patterns.
- We move towards unifying the `fn` front matter; this is fully realized in https://github.com/rust-lang/rust/pull/68728.
r? @petrochenkov
Account for HR lifetimes when suggesting introduction of named lifetime
```
error[E0106]: missing lifetime specifier
--> src/test/ui/suggestions/fn-missing-lifetime-in-item.rs:2:32
|
2 | struct S2<F: Fn(&i32, &i32) -> &i32>(F);
| ---- ---- ^ expected named lifetime parameter
|
= help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from argument 1 or argument 2
= note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
help: consider making the bound lifetime-generic with a new `'a` lifetime
|
2 | struct S2<F: for<'a> Fn(&'a i32, &'a i32) -> &'a i32>(F);
| ^^^^^^^ ^^^^^^^ ^^^^^^^ ^^^
help: consider introducing a named lifetime parameter
|
2 | struct S2<'a, F: Fn(&'a i32, &'a i32) -> &'a i32>(F);=
| ^^^ ^^^^^^^ ^^^^^^^ ^^^
```
Follow up to #68267. Addresses the diagnostics part of #49287.
Tweak obligation error output
- Point at arguments or output when fn obligations come from them, or ident when they don't
- Point at `Sized` bound (fix#47990)
- When object unsafe trait uses itself in associated item suggest using `Self` (fix#66424, fix#33375, partially address #38376, cc #61525)
- Point at reason in object unsafe trait with `Self` in supertraits or `where`-clause (cc #40533, cc #68377)
- On implicit type parameter `Sized` obligations, suggest `?Sized` (fix#57744, fix#46683)
Implement MIR lowering for or-patterns
This is the last thing needed to get meaningful run-pass tests for or-patterns. There probably need to be more tests before stabilizing this, but the most important cases should have been covered.
Note: we can generate exponentially large MIR CFGs when using or-patterns containing bindings, type ascriptions, or that are for a match arm with a guard. `src/test/mir-opt/exponential-or.rs` shows the best case for what we currently do.
cc #54883closes#60350closes#67514
cc @Centril
r? @pnkfelix
Remove incorrect debug assertions from catch_unwind
Previously the debug assertions in the implementation of catch_unwind
used to verify consistency of the panic count by checking that the count
is zero just before leaving the function. This incorrectly assumed that
no panic was in progress when entering `catch_unwind`.
Fixes#68696.
Address inconsistency in using "is" with "declared here"
"is" was generally used for NLL diagnostics, but not other diagnostics. Using "is" makes the diagnostics sound more natural and readable, so it seems sensible to commit to them throughout.
r? @Centril
Previously the debug assertions in the implementation of catch_unwind
used to verify consistency of the panic count by checking that the count
is zero just before leaving the function. This incorrectly assumed that
no panic was in progress when entering `catch_unwind`.
Move numeric consts to associated consts step1
A subset of #67913. Implements the first step of RFC https://github.com/rust-lang/rfcs/pull/2700
This PR adds the new constants as unstable constants and defines the old ones in terms of the new ones. Then fix a tiny bit of code that started having naming collisions because of the new assoc consts.
Removed a test that did not seem relevant any longer. Since doing just `u8::MIN` should now indeed be valid.
