Avoid pointing out `return` span if it has nothing to do with type error
This code:
```rust
fn f(_: String) {}
fn main() {
let x = || {
if true {
return ();
}
f("");
};
}
```
Emits this:
```
Compiling playground v0.0.1 (/playground)
error[E0308]: mismatched types
--> src/main.rs:8:11
|
8 | f("");
| ^^- help: try using a conversion method: `.to_string()`
| |
| expected struct `String`, found `&str`
|
note: return type inferred to be `String` here
--> src/main.rs:6:20
|
6 | return ();
| ^^
```
Specifically, that note has nothing to do with the type error in question. This is because the change implemented in #84244 tries to point out the `return` span on _any_ type coercion error within a closure that happens after a `return` statement, regardless of if the error has anything to do with it.
This is really easy to trigger -- just needs a closure (or an `async`) and an early return (or any other form, e.g. `?` operator suffices) -- and super distracting in production codebases. I'm letting #84128 regress because that issue is much harder to fix correctly, and I can re-open that issue after this lands.
As a drive-by, I added a `resolve_vars_if_possible` to the coercion error logic, which leads to some error improvements. Unrelated to the issue above, though.
Detect type mismatch due to loop that might never iterate
When loop as tail expression causes a miss match type E0308 error, recursively get the return statement and add diagnostic information on it.
when loop as tail expression for miss match type E0308 error, recursively get
the return statement and add diagnostic information on it
use rustc_hir::intravisit to collect the return expression
modified: compiler/rustc_typeck/src/check/coercion.rs
new file: src/test/ui/typeck/issue-98982.rs
new file: src/test/ui/typeck/issue-98982.stderr
Improve diagnostics for `const a: = expr;`
Adds a suggestion to write a type when there is a colon, but the type is not present.
I've also shrunk spans a little, so the suggestions are a little nicer.
Resolves#100146
r? `@compiler-errors`
Use `TraitEngine` in more places that don't specifically need `FulfillmentContext::new_in_snapshot`
Not sure if this change is worthwhile, but couldn't hurt re: chalkification
r? types
remove `commit_unconditionally`
`commit_unconditionally` is a noop unless we somehow inspect the current state of our snapshot. The only thing which does that is the leak check which was only used in one place where `commit_if_ok` is probably at least as, or even more, correct.
r? rust-lang/types
Add wrap suggestions for record variants
This PR adds a suggestions to wrap an expression in a record struct/variant when encountering mismatched types, similarly to a suggestion to wrap expression in a tuple struct that was added before.
An example:
```rust
struct B {
f: u8,
}
enum E {
A(u32),
B { f: u8 },
}
fn main() {
let _: B = 1;
let _: E = 1;
}
```
```text
error[E0308]: mismatched types
--> ./t.rs:11:16
|
11 | let _: B = 1;
| - ^ expected struct `B`, found integer
| |
| expected due to this
|
help: try wrapping the expression in `B`
|
11 | let _: B = B { f: 1 };
| ++++++ +
error[E0308]: mismatched types
--> ./t.rs:12:16
|
12 | let _: E = 1;
| - ^ expected enum `E`, found integer
| |
| expected due to this
|
help: try wrapping the expression in a variant of `E`
|
12 | let _: E = E::A(1);
| +++++ +
12 | let _: E = E::B { f: 1 };
| +++++++++ +
```
r? `@compiler-errors`
Use `impl`'s generics when suggesting fix on bad `impl Copy`
See the UI test for a more complicated example, but we weren't correctly suggesting to add bounds given a manual `impl` whose generics didn't match the struct generics.
```rust
#[derive(Clone)]
struct Wrapper<T>(T);
impl<S> Copy for Wrapper<S> {}
```
Coincidentally this fix didn't cause any regressions for `derive(Copy)` impls, I think because those use the same spans in the impl generics as the struct generics, so the machinery still applies the same change.
use `check_region_obligations_and_report_errors` to avoid ICEs
If we don't call `process_registered_region_obligations` before `resolve_regions_and_report_errors` then we'll ICE if we have any region obligations, and `check_region_obligations_and_report_errors` just does both of these for us in a nice convenient function.
Fixes#53475
r? types
Rollup of 8 pull requests
Successful merges:
- #99227 (Fix thumbv4t-none-eabi frame pointer setting)
- #99518 (Let-else: break out scopes when a let-else pattern fails to match)
- #99671 (Suggest dereferencing index when trying to use a reference of usize as index)
- #99831 (Add Fuchsia platform support documentation)
- #99881 (fix ICE when computing codegen_fn_attrs on closure with non-fn parent)
- #99888 (Streamline lint checking)
- #99891 (Adjust an expr span to account for macros)
- #99904 (Cleanup html whitespace)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Adjust an expr span to account for macros
Fix this erroneous suggestion:
```
error[E0529]: expected an array or slice, found `Vec<{integer}>`
--> /home/gh-compiler-errors/test.rs:2:9
|
2 | let [..] = vec![1, 2, 3];
| ^^^^ pattern cannot match with input type `Vec<{integer}>`
|
help: consider slicing here
--> /home/gh-compiler-errors/rust2/library/alloc/src/macros.rs:50:36
|
50~ $crate::__rust_force_expr!(<[_]>::into_vec(
51+ #[rustc_box]
52+ $crate::boxed::Box::new([$($x),+])
53~ )[..])
```
fix ICE when computing codegen_fn_attrs on closure with non-fn parent
Other call sites check `has_codegen_attrs` first, so let's do that too.
Fixes#99876
add suggestion when there is a impl of external trait on pointer with wrong coherence rules
Closes https://github.com/rust-lang/rust/issues/99572
This will try to improve the node in the error message by suggesting a general solution because the solution, in this case, is application depended.
I'm not super happy regarding the code quality, but I'm happy to have feedback on it.
`@rustbot` r? `@compiler-errors`
