contains ref-bindings, do not permit any upcasting from the type of
the value being matched. Similarly, do not permit coercion in a `let`.
This is a [breaking-change] in that it closes a type hole that
previously existed, and in that coercion is not performed. You should
be able to work around the latter by converting:
```rust
let ref mut x: T = expr;
```
into
```rust
let x: T = expr;
let ref mut x = x;
```
Restricting coercion not to apply in the case of `let ref` or `let ref mut` is sort
of unexciting to me, but seems the best solution:
1. Mixing coercion and `let ref` or `let ref mut` is a bit odd, because you are taking
the address of a (coerced) temporary, but only sometimes. It's not syntactically evident,
in other words, what's going on. When you're doing a coercion, you're kind of
2. Put another way, I would like to preserve the relationship that
`equality <= subtyping <= coercion <= as-coercion`, where this is
an indication of the number of `(T1,T2)` pairs that are accepted by
the various relations. Trying to mix `let ref mut` and coercion
would create another kind of relation that is like coercion, but
acts differently in the case where a precise match is needed.
3. In any case, this is strictly more conservative than what we had
before and we can undo it in the future if we find a way to make
coercion mix with type equality.
The change to match I feel ok about but similarly unthrilled. There is
some subtle text already concerning whether to use eqtype or subtype
for identifier bindings. The best fix I think would be to always have
match use strict equality but use subtyping on identifier bindings,
but the comment `(*)` explains why that's not working at the moment.
As above, I think we can change this as we clean up the code there.
Linking __pthread_get_minstack, even weakly, was causing Debian’s
dpkg-shlibdeps to detect an unnecessarily strict versioned dependency
on libc6.
Closes#23628.
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Boolean values and small aggregates have a different type in args/allocas than
in SSA values but the intrinsics for volatile and atomic ops were
missing the necessary casts to handle that.
Fixes#23550
This commit removes the `IndexMut` impls on `HashMap` and `BTreeMap`, in
order to future-proof the API against the eventual inclusion of an
`IndexSet` trait.
Ideally, we would eventually be able to support:
```rust
map[owned_key] = val;
map[borrowed_key].mutating_method(arguments);
&mut map[borrowed_key];
```
but to keep the design space as unconstrained as possible, we do not
currently want to support `IndexMut`, in case some other strategy will
eventually be needed.
Code currently using mutating index notation can use `get_mut` instead.
[breaking-change]
Closes#23448
r? @Gankro
For the rust-call ABI, the last function argument is a tuple that gets
untupled for the actual call. For bare functions using this ABI, the
code has access to the tuple, so we need to tuple the arguments again.
But closures can't actually access the tuple. Their arguments map to the
elements in the tuple. So what we currently do is to tuple the arguments
and then immediately untuple them again, which is pretty useless and we
can just omit it.
After this patch code like `let ref a = *"abcdef"` doesn't cause ICE anymore.
Required for #23121
There are still places in rustc_trans where pointers are always assumed to be thin. In particular, #19064 is not resolved by this patch.
There have been some recent panics on the bots and this commit is an attempt to
appease them. Previously it was considered invalid to run `rt::at_exit` after
the handlers had already started running. Due to the multithreaded nature of
applications, however, it is not always possible to guarantee this. For example
[this program][ex] will show off the abort.
[ex]: https://gist.github.com/alexcrichton/56300b87af6fa554e52d
The semantics of the `rt::at_exit` function have been modified as such:
* It is now legal to call `rt::at_exit` at any time. The return value now
indicates whether the closure was successfully registered or not. Callers must
now decide what to do with this information.
* The `rt::at_exit` handlers will now be run for a fixed number of iterations.
Common cases (such as the example shown) may end up registering a new handler
while others are running perhaps once or twice, so this common condition is
covered by re-running the handlers a fixed number of times, after which new
registrations are forbidden.
Some usage of `rt::at_exit` was updated to handle these new semantics, but
deprecated or unstable libraries calling `rt::at_exit` were not updated.
The method with which backwards compatibility was retained ended up leading to
documentation that rustdoc didn't handle well and largely ended up confusing.
Boolean values and small aggregates have a different type in
args/allocas than in SSA values but the intrinsics for volatile and
atomic ops were missing the necessary casts to handle that.
Fixes#23550
This commit removes the reexports of `old_io` traits as well as `old_path` types
and traits from the prelude. This functionality is now all deprecated and needs
to be removed to make way for other functionality like `Seek` in the `std::io`
module (currently reexported as `NewSeek` in the io prelude).
Closes#23377Closes#23378
This commit removes the reexports of `old_io` traits as well as `old_path` types
and traits from the prelude. This functionality is now all deprecated and needs
to be removed to make way for other functionality like `Seek` in the `std::io`
module (currently reexported as `NewSeek` in the io prelude).
Closes#23377Closes#23378
This reverts commit aec67c2.
Closes#20012
This is temporarily rebased on #23245 as it would otherwise conflict, the last commit is the only one relevant to this PR though.
This commit removes the `IndexMut` impls on `HashMap` and `BTreeMap`, in
order to future-proof the API against the eventual inclusion of an
`IndexSet` trait.
Ideally, we would eventually be able to support:
```rust
map[owned_key] = val;
map[borrowed_key].mutating_method(arguments);
&mut map[borrowed_key];
```
but to keep the design space as unconstrained as possible, we do not
currently want to support `IndexMut`, in case some other strategy will
eventually be needed.
Code currently using mutating index notation can use `get_mut` instead.
[breaking-change]
Closes#23448
