Fix borrow checker unsoundness with unions
Fixes#45157. After discussion with @nikomatsakis on Gitter, this PR only adds a test since the original issue was resolved elsewhere.
r? @nikomatsakis
Remove "static item recursion checking" in favor of relying on cycle checks in the query engine
Tests are changed to use the cycle check error message instead. Some duplicate tests are removed.
r? @eddyb
Overhaul improper_ctypes output
This snowballed into a rather big set of improvements to the diagnostics of the improper_ctypes lint. See commits for details, including effects of each change on the `compile-fail/improper-ctypes.rs` test (now a UI test), which is pretty gnarly and hopefully not representative of real code, but covers a lot of different error cases.
Fixes#42050
detect wrong number of args when type-checking a closure
Instead of creating inference variables for those argument types, use
the trait error-reporting code to give a nicer error. This also
improves some other spans for existing tests.
Fixes#47244
r? @estebank
Fix span of visibility
This PR
1. adds a closing parenthesis to the span of `Visibility::Crate` (e.g. `pub(crate)`). The current span only covers `pub(crate`.
2. adds a `span` field to `Visibility::Restricted`. This span covers the entire visibility expression (e.g. `pub (in self)`). Currently all we can have is a span for `Path`.
This PR is motivated by the bug found in rustfmt (https://github.com/rust-lang-nursery/rustfmt/issues/2398).
The first change is a strict improvement IMHO. The second change may not be desirable, as it adds a field which is currently not used by the compiler.
rustc_mir: handle all aggregate kinds in, and always run, the deaggregator.
This helps with removing`Rvalue::Aggregate` from the MIR, and with enabling more optimizations.
r? @nikomatsakis
It's unhelpful since raw pointers to trait objects are also FFI-unsafe and casting to a thin raw pointer loses the vtable. There are working solutions that _involve_ raw pointers but they're too complex to explain in one line and have serious trade offs.
The suggestion is unconditional, so following it could lead to further errors. This is already the case for the repr(C) suggestion, which makes this acceptable, though not *good*. Checking up-front whether the suggestion can help would be great but applies more broadly (and would require some refactoring to avoid duplicating the checks).
- Always name the non-FFI-safe
- Explain *why* the type is not FFI-safe
- Stop vaguely gesturing at structs/enums/unions if the non-FFI-safe types occured in a field.
The last part is arguably a regression, but it's minor now that the non-FFI-safe type is actually named. Removing it avoids some code duplication.
Continue parsing function after finding `...` arg
When encountering a variadic argument in a function definition that
doesn't accept it, if immediately after there's a closing paren,
continue parsing as normal. Otherwise keep current behavior of emitting
error and stopping.
Fix#31481.
When encountering a variadic argument in a function definition that
doesn't accept it, if immediately after there's a closing paren,
continue parsing as normal. Otherwise keep current behavior of emitting
error and stopping.
rustc_mir: insert a dummy access to places being matched on, when building MIR.
Fixes#47412 by adding a `_dummy = Discriminant(place)` before each `match place {...}`.
r? @nikomatsakis
Fix ICE for mismatched args on target without span
Commit 7ed00caacc improved our error reporting by including the target function in our error messages when there is an argument count mismatch. A simple example from the UI tests is:
```
error[E0593]: function is expected to take a single 2-tuple as argument, but it takes 0 arguments
--> $DIR/closure-arg-count.rs:32:53
|
32 | let _it = vec![1, 2, 3].into_iter().enumerate().map(foo);
| ^^^ expected function that takes a single 2-tuple as argument
...
44 | fn foo() {}
| -------- takes 0 arguments
```
However, this assumed the target span was always available. This does not hold true if the target function is in `std` or another crate. A simple example from #48046 is assigning `str::split` to a function type with a different number of arguments.
Fix by omitting all of the labels and suggestions related to the target span when it's not found.
Fixes#48046
r? @estebank
