use structured suggestion for method calls
Furthermore, don't suggest calling the method if it is part of a place
expression, as this is invalid syntax.
I'm thinking it might be worth putting a label on the method assignment span like "this is a method" and removing the span from the "methods are immutable" text so it isn't reported twice.
The suggestions in `src/test/ui/did_you_mean/issue-40396.stderr` are suboptimal. I could check if the containing expression is `BinOp`, but I'm not sure if that's general enough. Any ideas?
r? @estebank
Fix#56806 by using `delay_span_bug` in object safety layout sanity checks
It's possible that `is_object_safe` is called on a trait method that with an invalid receiver type. This caused an ICE in #56806, because `receiver_is_dispatchable` returns `true` for `self: Box<dyn Trait>`, which causes one of the layout sanity checks in object_safety.rs to fail. Replacing `bug!` with `delay_span_bug` solves this.
The fact that `receiver_is_dispatchable` returns `true` here could be considered a bug. It passes the check that the method implements, though: `Box<dyn Trait>` implements `DispatchFromDyn<Box<dyn Trait>>` because `dyn Trait` implements `Unsize<dyn Trait>`. It would be good to hear what @eddyb and @nikomatsakis think.
Note that I only added a test for the case encountered in #56806. I could not come up with a case that triggered an ICE from the other check, `bug!("receiver when Self = dyn Trait should be ScalarPair, found Scalar")`. There is no way, to my knowledge, that you can make `receiver_is_dispatchable` return true but still have a `Scalar` ABI when `Self = dyn Trait`.
One other case I encountered while debugging #56806 was that if you have a type parameter `T` that implements `Deref<Target=Self>` and `DispatchFromDyn<T>`, and use it as a method receiver, it will cause an ICE during `is_object_safe` because `T` has no layout ([playground](https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=d9b7497b3be0ca8382fa7d9497263214)):
```rust
trait Trait<T: Deref<Target=Self> + DispatchFromDyn<T>> {
fn foo(self: T) -> dyn Trait<T>;
}
```
I don't intend to remove the ICE there because it is a pathological case, especially since there is no way to implement `DispatchFromDyn<T>` for `T` — the checks in typeck/coherence/builtin.rs do not allow that.
fixes#56806
r? @varkor
Add support for trait-objects without a principal
The hard-error version of #56481 - should be merged after we do something about the `traitobject` crate.
Fixes#33140.
Fixes#57057.
r? @nikomatsakis
It's possible that `is_object_safe` is called on a trait that is ill-formed, and we shouldn't ICE unless there are no errors being raised. Using `delay_span_bug` solves this.
fixes#56806
make `panictry!` private to libsyntax
This commit completely removes usage of the `panictry!` macro from
outside libsyntax. The macro causes parse errors to be fatal, so using
it in libsyntax_ext caused parse failures *within* a syntax extension to
be fatal, which is probably not intended.
Furthermore, this commit adds spans to diagnostics emitted by empty
extensions if they were missing, à la #56491.
This commit completely removes usage of the `panictry!` macro from
outside libsyntax. The macro causes parse errors to be fatal, so using
it in libsyntax_ext caused parse failures *within* a syntax extension to
be fatal, which is probably not intended.
Furthermore, this commit adds spans to diagnostics emitted by empty
extensions if they were missing, à la #56491.
Improve type mismatch error messages
Closes#56115.
Replace "integral variable" with "integer" and replace "floating-point variable" with "floating-point number" to make the message less confusing.
TODO the book and clippy needs to be changed accordingly later.
r? @varkor
privacy: Use common `DefId` visiting infrastructure for all privacy visitors
One repeating pattern in privacy checking is going through a type, visiting all `DefId`s inside it and doing something with them.
This is the case because visibilities and reachabilities are attached to `DefId`s.
Previously various privacy visitors visited types slightly differently using their own methods, with most recently written `TypePrivacyVisitor` being the "gold standard".
This mostly worked okay, but differences could manifest in overly conservative reachability analysis, some errors being reported twice, some private-in-public lints (not errors) being wrongly reported or not reported.
This PR does something that I wanted to do since https://github.com/rust-lang/rust/pull/32674#discussion_r58291608 - factoring out the common visiting logic!
Now all the common logic is contained in `struct DefIdVisitorSkeleton`, with specific privacy visitors deciding only what to do with visited `DefId`s (via `trait DefIdVisitor`).
A bunch of cleanups is also applied in the process.
This area is somewhat tricky due to lots of easily miss-able details, but thankfully it's was well covered by tests in https://github.com/rust-lang/rust/pull/46083 and previous PRs, so I'm relatively sure in the refactoring correctness.
Fixes https://github.com/rust-lang/rust/pull/56837#discussion_r241962239 in particular.
Also this will help with implementing https://github.com/rust-lang/rust/issues/48054.
Implement RFC 2338, "Type alias enum variants"
This PR implements [RFC 2338](https://github.com/rust-lang/rfcs/pull/2338), allowing one to write code like the following.
```rust
#![feature(type_alias_enum_variants)]
enum Foo {
Bar(i32),
Baz { i: i32 },
}
type Alias = Foo;
fn main() {
let t = Alias::Bar(0);
let t = Alias::Baz { i: 0 };
match t {
Alias::Bar(_i) => {}
Alias::Baz { i: _i } => {}
}
}
```
Since `Self` can be considered a type alias in this context, it also enables using `Self::Variant` as both a constructor and pattern.
Fixes issues #56199 and #56611.
N.B., after discussing the syntax for type arguments on enum variants with @petrochenkov and @eddyb (there are also a few comments on the [tracking issue](https://github.com/rust-lang/rust/issues/49683)), the consensus seems to be treat the syntax as follows, which ought to be backwards-compatible.
```rust
Option::<u8>::None; // OK
Option::None::<u8>; // OK, but lint in near future (hard error next edition?)
Alias::<u8>::None; // OK
Alias::None::<u8>; // Error
```
I do not know if this will need an FCP, but let's start one if so.
AST/HIR: Introduce `ExprKind::Err` for better error recovery in the front-end
This way we can avoid aborting compilation if expansion produces errors and generate `ExprKind::Err`s instead.
- Point at opening mismatched formatting brace
- Account for differences between raw and regular strings
- Account for differences between the code snippet and `InternedString`
- Add more tests
