Account for common `impl Trait`/`dyn Trait` return type errors
- When all return paths have the same type, suggest `impl Trait`.
- When all return paths implement the expected `trait`, suggest `Box<dyn Trait>` and mention using an `enum`.
- When multiple different types are returned and `impl Trait` is expected, extend the explanation.
- When return type is `impl Trait` and the return paths do not implement `Trait`, point at the returned values.
- Split `src/librustc/traits/error_reporting.rs` into multiple files to keep size under control.
Fix#68110, cc #66523.
When -Z panic_abort_tests is enabled, we use an environment variable to
tell the subprocess which test to invoke. If that subprocess then
invokes another Rust test binary, chaos ensues.
Implement `DebugStruct::non_exhaustive`.
This patch adds a function (finish_non_exhaustive) to add ellipsis before the closing brace when formatting using `DebugStruct`.
## Example
```rust
#![feature(debug_non_exhaustive)]
use std::fmt;
struct Bar {
bar: i32,
hidden: f32,
}
impl fmt::Debug for Bar {
fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt.debug_struct("Bar")
.field("bar", &self.bar)
.non_exhaustive(true) // Show that some other field(s) exist.
.finish()
}
}
assert_eq!(
format!("{:?}", Bar { bar: 10, hidden: 1.0 }),
"Bar { bar: 10, .. }",
);
```
Fixes#68264
Previously, I attempted to use
`substitute_normalize_and_test_predicates` to detect unsatisfiable
bounds. Unfortunately, since const-prop runs in a generic environment
(we don't have any of the function's generic parameters substituted),
this could lead to cycle errors when attempting to normalize predicates.
This check is replaced with a more precise check. We now only call
`normalize_and_test_predicates` on predicates that have the possibility
of being proved unsatisfiable - that is, predicates that don't depend
on anything local to the function (e.g. generic parameters). This
ensures that we don't hit cycle errors when we normalize said
predicates, while still ensuring that we detect unsatisfiable
predicates.
Rollup of 5 pull requests
Successful merges:
- #68033 (Don't use f64 shims for f32 cmath functions on non 32-bit x86 MSVC)
- #68244 (Enable leak sanitizer test case)
- #68255 (Remove unused auxiliary file that was replaced with rust_test_helpers)
- #68263 (rustdoc: HTML escape codeblocks which fail syntax highlighting)
- #68274 (remove dead code)
Failed merges:
r? @ghost
When a type error involves a `dyn Trait` as the return type, do not emit
the type error, as the "return type is not `Sized`" error will provide
enough information to the user.
remove dead code
The condition
`if obligation.recursion_depth >= 0`
is always true since `recursion_depth` is `usize`.
The else branch is dead code and can be removed.
Found by Clippy.
Fixes#68251
Enable leak sanitizer test case
* Use `black_box` to avoid memory leak removal during optimization.
* Leak multiple objects to make test case more robust.
