Two changes:
1. Make traits with assoc types invariant w/r/t their inputs.
2. Fully normalize parameter environments, including any region variables (which were being overlooked).
The former supports the latter, but also just seems like a reasonably good idea.
Fixes#21750
cc @edwardw
r? @pnkfelix
This is a fix for #20300 though as a side-sweep it fixes a number of stack overflows because it integrates cycle detection into the conversion process. I didn't go through and retest everything.
The tricky part here is that in some cases we have to go find the information we need from the AST -- we can't use the converted form of the where-clauses because we often have to handle something like `T::Item` *while converting the where-clauses themselves*. Since this is also not a fixed-point process we can't just try and keep trying to find the best order. So instead I modified the `AstConv` interface to allow you to request the bounds for a type parameter; we'll then do a secondary scan of the where-clauses to figure out what we need. This may create a cycle in some cases, but we have code to catch that.
Another approach that is NOT taken by this PR would be to "convert" `T::Item` into a form that does not specify what trait it's using. This then kind of defers the problem of picking the trait till later. That might be a good idea, but it would make normalization and everything else much harder, so I'm holding off on that (and hoping to find a better way for handling things like `i32::T`).
This PR also removes "most of" the `bounds` struct from `TypeParameterDef`. Still a little ways to go before `ParamBounds` can be removed entirely -- it's used for supertraits, for example (though those really ought to be converted, I think, to a call to `get_type_parameter_bounds` on `Self` from within the trait definition).
cc @jroesch
Fixes#20300
This commit moves `std::env` away from the `std::old_io` error type as well as
the `std::old_path` module. Methods returning an error now return `io::Error`
and methods consuming or returning paths use `std::path` instead of
`std::old_path`. This commit does not yet mark these APIs as `#[stable]`.
This commit also migrates `std::old_io::TempDir` to `std::fs::TempDir` with
essentially the exact same API. This type was added to interoperate with the new
path API and has its own `tempdir` feature.
Finally, this commit reverts the deprecation of `std::os` APIs returning the old
path API types. This deprecation can come back once the entire `std::old_path`
module is deprecated.
[breaking-change]
Specifically, the following actions were taken:
* The `copy_memory` and `copy_nonoverlapping_memory` functions
to drop the `_memory` suffix (as it's implied by the functionality). Both
functions are now marked as `#[stable]`.
* The `set_memory` function was renamed to `write_bytes` and is now stable.
* The `zero_memory` function is now deprecated in favor of `write_bytes`
directly.
* The `Unique` pointer type is now behind its own feature gate called `unique`
to facilitate future stabilization.
* All type parameters now are `T: ?Sized` wherever possible and new clauses were
added to the `offset` functions to require that the type is sized.
[breaking-change]
I tried to follow [the style guide][1] as much as possible. This is just from some random readings of the code, so no guarantees on completeness, even in the edited files.
[1]: http://aturon.github.io/style/README.html
This affects the `set_non_blocking` function which cannot fail for Unix or
Windows, given correct parameters. Additionally, the short UDP write error case
has been removed as there is no such thing as \"short UDP writes\", instead, the
operating system will error out if the application tries to send a packet
larger than the MTU of the network path.
Tests often use `vec![1, 2, 3]` instead of shorter and faster `[1, 2, 3]`.
This patch removes a lot of unnecessary `vec!`s. Hopefully, the tests will compile and run a bit faster.
report are not *necessary* cycles, but we'll work on refactoring them
over time. This overlaps with the cycle detection that astconv already
does: I left that code in because it gives a more targeted error
message, though perhaps less helpful in that it doesn't give the full
details of the cycle.
Fixes#22525
I wasn't sure if I should reuse `write::get_llvm_opt_level` or not. It returns an `llvm::CodeGenOptLevel`, which is the Rust binding for `CodeGenOpt::Level`. `lto.rs` is passing an optlevel to LLVM's `PassManagerBuilder`, which takes an unsigned int. `PassManagerBuilder`'s optlevel uses essentially the same enumeration (i.e. 0-3 with 2 as default), but it's implicit.
Adds `<module::Type>::method` support and makes `module::Type::method` a shorthand for it.
This is most of #16293, except that chaining multiple associated types is not yet supported.
It also fixes#22563 as `impl`s are no longer treated as modules in resolve.
Unfortunately, this is still a *[breaking-change]*:
* If you used a global path to a primitive type, i.e. `::bool`, `::i32` etc. - that was a bug I had to fix.
Solution: remove the leading `::`.
* If you passed explicit `impl`-side type parameters to an inherent method, e.g.:
```rust
struct Foo<T>(T);
impl<A, B> Foo<(A, B)> {
fn pair(a: A, b: B) -> Foo<(A, B)> { Foo((a, b)) }
}
Foo::<A, B>::pair(a, b)
// Now that is sugar for:
<Foo<A, B>>::pair(a, b)
// Which isn't valid because `Foo` has only one type parameter.
// Solution: replace with:
Foo::<(A, B)>::pair(a, b)
// And, if possible, remove the explicit type param entirely:
Foo::pair(a, b)
```
* If you used the `QPath`-related `AstBuilder` methods @hugwijst added in #21943.
The methods still exist, but `QPath` was replaced by `QSelf`, with the actual path stored separately.
Solution: unpack the pair returned by `cx.qpath` to get the two arguments for `cx.expr_qpath`.
