Update if-let.md
Calling if-let a combination of if and let is confusing, as some may be led to believe that it's a literal combination, instead of syntactic sugar added to the language as a convenience. What's there to stop someone from thinking if-let is just if and let together?
I do think this article does a good job of implying what's really going on; however, I was only able to notice this after I had begun to understand if/while-let statements, courtesy of the Rust IRC chat.
Basically, this article lacks the clarity and explicitness an inexperienced programmer like me needs in order to understand the contents fully. This is shown by my inability to understand the if-let concept from this page of the Book alone.
I think convenience, sugar, and (if-let != if + let) should all be made mention of in a clear, explicit manner. I lack confidence in my understanding of this issue, so I wrote just enough to hopefully get my thoughts across.
make lifetimes that only appear in return type early-bound
This is the full and proper fix for #32330. This also makes some effort to give a nice error message (as evidenced by the `ui` test), sending users over to the tracking issue for a fuller explanation and offering a `--explain` message in some cases.
This needs a crater run before we land.
r? @arielb1
This is the full and proper fix for #32330. This also makes some effort
to give a nice error message (as evidenced by the `ui` test), sending
users over to the tracking issue for a full explanation.
ignore more gdb versions with buggy rust support
This extends the versions of gdb which were ignored in #39039. While just ignoring gdb versions up to 7.12.1 would have been sufficient for now, I believe (after consulting https://sourceware.org/gdb/wiki/Internals%20Versions) that ignoring versions up to 7.12.9 will prevent the tests failing again for 7.12.2, etc. while still running all tests for the development versions of gdb (which will be >= 7.12.10 as far as I can tell).
This should fix#39522.
cc @Manishearth, @michaelwoerister, #38948
[LLVM 4.0] Support a debug info API change for LLVM 4.0
Instead of directly creating a `DIGlobalVariable`, we now have to create
a `DIGlobalVariableExpression` which itself contains a reference to a
'DIGlobalVariable'.
This is a straightforward change.
In the future, we should rename `DIGlobalVariable` in the FFI
bindings, assuming we will only refer to `DIGlobalVariableExpression`
and not `DIGlobalVariable`.
Uninhabited while-let pattern fix
This fix makes it so while-let with an unsatisfiable pattern raises a correct warning rather than an incorrect error.
Use less syscalls in `FileDesc::set_{nonblocking,cloexec}`
Only set the flags if they differ from what the OS reported, use
`FIONBIO` to atomically set the non-blocking IO flag on Linux.
Don't use "unadjusted" ABI on non windows platforms
We introduced the unadjusted ABI to work around wrong
(buggy) ABI expectations by LLVM on Windows [1].
Therefore, it should be solely used on Windows and not
on other platforms, like right now is the case.
[1]: see this comment for details https://github.com/rust-lang/rust/pull/38482#issuecomment-269074031
Fix TryFrom for i128/u128
Another case of `as` cast silent truncation being error prone.
This also adds a few missing TryFrom tests to libcoretest.
cc #33417
cc #35118
Add a name for the parameter to `TryFrom::try_from`.
Although signatures with anonymous parameters may not be deprecated or removed at this point, the team seems to agree that the ability to have an anonymous parameter is unfortunate historical baggage, and that we shouldn't create new code that uses it.
Context: https://github.com/rust-lang/rust/issues/33417#issuecomment-276933861
Don't suggest to use things which weren't found either
Fixes#38054
The best code I can come up with, suggestions are welcome.
Basically, removing ```. Did you mean to use `DoesntExist1`?``` in the code below, because it is useless.
```rust
error[E0432]: unresolved import `DoesntExist1`
--> src/lib.rs:1:5
|
1 | use DoesntExist1;
| ^^^^^^^^^^^^ no `DoesntExist1` in the root
error[E0432]: unresolved import `DoesntExist2`
--> src/lib.rs:2:5
|
2 | use DoesntExist2;
| ^^^^^^^^^^^^ no `DoesntExist2` in the root. Did you mean to use `DoesntExist1`?
```
Expand derive macros in the MacroExpander
This removes the expand_derives function, and sprinkles the functionality throughout the Invocation Collector, Expander and Resolver.
Fixes https://github.com/rust-lang/rust/issues/39326
r? @jseyfried
Fix full path being output with `rustdoc -h`
rustdoc would output the full path to the binary when calling it with
the `-h` or `--help` flags. This is undesired behavior. It has been
replaced with a hardcoded string `rustdoc` to fix the issue.
Fixes#39310
Provide Entry-like API for Option
This implements #39288.
I am wondering whether to use std::intrinsics::unreachable!() here. Both seems fine to me (the second match optimizes away in release mode).
branchless .filter(_).count()
I found that the branchless version is only slower if we have little to no branch misses, which usually isn't the case. I notice speedups between -5% (perfect prediction) and 60% (real world data).
Add warning for () to ! switch
With feature(never_type) enabled diverging type variables will default to `!` instead of `()`. This can cause breakages where a trait is resolved on such a type.
This PR emits a future-compatibility warning when it sees this happen.
Add peek APIs to std::net
Adds "peek" APIs to `std::net` sockets, including:
- `UdpSocket.peek()`
- `UdpSocket.peek_from()`
- `TcpStream.peek()`
These methods enable socket reads without side-effects. That is, repeated calls to `peek()` return identical data. This is accomplished by providing the POSIX flag `MSG_PEEK` to the underlying socket read operations.
This also moves the current implementation of `recv_from` out of the platform-independent `sys_common` and into respective `sys/windows` and `sys/unix` implementations. This allows for more platform-dependent implementations where necessary.
Fixes#38980
Add 128-bit atomics
This is currently only supported on AArch64 since that is the only target which unconditionally supports 128-bit atomic operations.
cc #35118
Support unprivileged symlink creation in Windows
Symlink creation on Windows has in the past basically required admin; it’s being opened up a bit in the Creators Update, so that at least people who have put their computers into Developer Mode will be able to create symlinks without special privileges. (It’s unclear from what Microsoft has said whether Developer Mode will be required in the final Creators Update release, but sadly I expect it still will be, so this *still* won’t be as helpful as I’d like.)
Because of compatibility concerns, they’ve hidden this new functionality behind a new flag in the CreateSymbolicLink dwFlags: `SYMBOLIC_LINK_FLAG_ALLOW_UNPRIVILEGED_CREATE`. So we add this flag in order to join the party.
Sources:
- https://blogs.windows.com/buildingapps/2016/12/02/symlinks-windows-10/ is the official announcement (search for CreateSymbolicLink)
- https://news.ycombinator.com/item?id=13096354 on why the new flag.
Expand documentation of process::exit and exec
Show a conventional way to use process::exit when destructors are considered important and also
mention that the same caveats wrt destructors apply to exec as well.
rustdoc: fix doctests with non-feature crate attrs
Fixes#38129.
The book says that any top-level crate attributes at the beginning of a doctest are moved outside the generated `fn main`, but it was only checking for `#
