check it more easily; also extend object safety to cover sized types
as well as static methods. This makes it sufficient so that we can
always ensure that `Foo : Foo` holds for any trait `Foo`.
These changes fix various problems encountered getting japaric's `at-iter` branch to work. This branch converts the `Iterator` trait to use an associated type.
Doesn't yet converge on a fixed point, but generally works. A better algorithm
will come with the implementation of default type parameter fallback.
If inference fails to determine an exact integral or floating point type, it
will set the type to i32 or f64, respectively.
Closes#16968
Doesn't yet converge on a fixed point, but generally works. A better algorithm
will come with the implementation of default type parameter fallback.
If inference fails to determine an exact integral or floating point type, it
will set the type to i32 or f64, respectively.
Closes#16968
Uses the same approach as https://github.com/rust-lang/rust/pull/17286 (and
subsequent changes making it more correct), where the visitor will skip any
pieces of the AST that are from "foreign code", where the spans don't line up,
indicating that that piece of code is due to a macro expansion.
If this breaks your code, read the error message to determine which feature
gate you should add to your crate.
Closes#18102
[breaking-change]
Uses the same approach as https://github.com/rust-lang/rust/pull/17286 (and
subsequent changes making it more correct), where the visitor will skip any
pieces of the AST that are from "foreign code", where the spans don't line up,
indicating that that piece of code is due to a macro expansion.
If this breaks your code, read the error message to determine which feature
gate you should add to your crate, and bask in the knowledge that your code
won't mysteriously break should you try to use the 1.0 release.
Closes#18102
[breaking-change]
The the last argument of the `ItemDecorator::expand` method has changed to `Box<FnMut>`. Syntax extensions will break.
[breaking-change]
---
This PR removes pretty much all the remaining uses of boxed closures from the libraries. There are still boxed closures under the `test` directory, but I think those should be removed or replaced with unboxed closures at the same time we remove boxed closures from the language.
In a few places I had to do some contortions (see the first commit for an example) to work around issue #19596. I have marked those workarounds with FIXMEs. In the future when `&mut F where F: FnMut` implements the `FnMut` trait, we should be able to remove those workarounds. I've take care to avoid placing the workaround functions in the public API.
Since `let f = || {}` always gets type checked as a boxed closure, I have explictly annotated those closures (with e.g. `|&:| {}`) to force the compiler to type check them as unboxed closures.
Instead of removing the type aliases (like `GetCrateDataCb`), I could have replaced them with newtypes. But this seemed like overcomplicating things for little to no gain.
I think we should be able to remove the boxed closures from the languge after this PR lands. (I'm being optimistic here)
r? @alexcrichton or @aturon
cc @nikomatsakis
is still probably wrong since it fails to incorporate the ambiguity
resolution measures that `select` uses. Also, made more complicated by
the fact that trait object types do not impl their own traits yet.
This pull request adds the `rust-gdb` shell script which starts GDB with Rust pretty printers enabled. The PR also makes `rustc` add a special `.debug_gdb_scripts` ELF section on Linux which tells GDB that the produced binary should use the Rust pretty printers.
Note that at the moment this script will only work and be installed on Linux. On Mac OS X there's `rust-lldb` which works much better there. On Windows I had too many problems making this stable. I'll give it another try soonish.
You can use this script just like you would use GDB from the command line. It will use the pretty printers from the Rust "installation" found first in PATH. E.g. if you have `~/rust/x86_64-linux-gnu/stage1/bin` in your path, it will use the pretty printer scripts in `~/rust/x86_64-linux-gnu/stage1/lib/rustlib/etc`.
Rewrite associated types to use projection rather than dummy type parameters. This closes almost every (major) open issue, but I'm holding off on that until the code has landed and baked a bit. Probably it should have more tests, as well, but I wanted to get this landed as fast as possible so that we can collaborate on improving it.
The commit history is a little messy, particularly the merge commit at the end. If I get some time, I might just "reset" to the beginning and try to carve up the final state into logical pieces. Let me know if it seems hard to follow. By far the most crucial commit is "Implement associated type projection and normalization."
r? @nick29581
for lack of impl-trait-for-trait just a bit more targeted (don't
substitute err, just drop the troublesome bound for now) -- otherwise
substituting false types leads us into trouble when we normalize etc.
1. Produced more unique types than is necessary. This increases memory consumption.
2. Linking the type parameter to its definition *seems* like a good idea, but it
encourages reliance on the bounds listing.
3. It made pretty-printing harder and in particular was causing bad error messages
when errors occurred before the `TypeParameterDef` entries were fully stored.
