When translating the unboxing shim, account for the fact that the shim translation has already performed the necessary unboxing of input types and values when forwarding to the shimmed function. This prevents ICEing or generating incorrect code.
Closes#16739
Check object lifetime bounds in coercions, not just trait bounds. Fixes#18055.
r? @pcwalton
This is a [breaking change]. Change code like this:
fn foo(v: &[u8]) -> Box<Clone+'static> { ... }
to make the lifetimes agree:
// either...
fn foo(v: &'static[u8]) -> Box<Clone+'static> { box v }
// or ...
fn foo<'a>(v: &'a [u8]) -> Box<Clone+'a> { box v }
The representability-checking routine ```is_type_representable``` failed to detect structural recursion in some cases, leading to stack overflow later on.
The first problem was in the loop in the ```find_nonrepresentable``` function. We were improperly terminating the iteration if we saw a ```ContainsRecursive``` condition. We should have kept going in case a later member of the struct (or enum, etc) being examined was ```SelfRecursive```. The example from #17431 triggered this issue:
```rust
use std::sync::Mutex;
struct Foo { foo: Mutex<Option<Foo>> }
impl Foo { fn bar(self) {} }
fn main() {}
```
I'm not 100% sure, but I think the ```ty_enum``` case of ```fn type_structurally_recursive``` had a similar problem, since it could ```break``` on ```ContainsRecursive``` before looking at all variants. I've replaced this with a ```flat_map``` call.
The second problem was that we were failing to identify code like ```struct Foo { foo: Option<Option<Foo>> }``` as SelfRecursive, even though we correctly identified ```struct Foo { foo: Option<Foo> }```. This was caused by using DefId's for the ```ContainsRecursive``` check, which meant the nested ```Option```s were identified as illegally recursive (because ```ContainsRecursive``` is not an error, we would then keep compiling and eventually hit a stack overflow).
In order to make sure that we can recurse through the different ```Option``` invocations, I've changed the type of ```seen``` from ```Vec<DefId>``` to ```Vec<t>``` and added a separate ```same_type``` function to check whether two types are the same when generics are taken into account. Now we only return ```ContainsRecursive``` when this stricter check is satisfied. (There's probably a better way to do this, and I'm not sure my code is entirely correct--but my knowledge of rustc internals is pretty limited, so any help here would be appreciated!)
Note that the ```SelfRecursive``` check is still comparing ```DefId```s--this is necessary to prevent code like this from being allowed:
```rust
struct Foo { x: Bar<Foo> }
struct Bar<T> { x: Bar<Foo> }
```
All four of the new ```issue-17431``` tests cause infinite recursion on master, and errors with this pull request. I wrote the extra ```issue-3008-4.rs``` test to make sure I wasn't introducing a regression.
Fixes#17431.
This adds ‘help’ diagnostic messages to rustc. This is used for anything that provides help to the user, particularly the `--explain` messages that were previously integrated into the relevant error message.
They look like this:
```
match.rs:10:13: 10:14 error: unreachable pattern [E0001]
match.rs:10 1 => {},
^
match.rs:3:1: 3:38 note: in expansion of foo!
match.rs:7:5: 20:2 note: expansion site
match.rs:10:13: 10:14 help: pass `--explain E0001` to see a detailed explanation
```
(`help` is coloured cyan.) Adding these errors on a separate line stops the lines from being too long, as discussed in #16619.
detected (correctly) that there was only one impl and hence ignored the
`Self` bound completely. I (semi-arbitrarily) elected to delect the
impl, forcing the trait matcher to be more conservative and lean on the
where clauses in scope, yielding the original error message.
On 32-bit architectures, the size calculations on two of the tests wrap-around
in typeck, which gives the relevant arrays a size of 0, which is (correctly)
successfully allocated.
This is some improvement as asked and discused here: http://www.reddit.com/r/rust/comments/2j2ij3/benchmark_improvement_reverse_compliment/
Before:
```
real 0m0.396s
user 0m0.280s
sys 0m0.112s
```
after:
```
real 0m0.293s
user 0m0.216s
sys 0m0.076s
```
best C version:
```
real 0m0.135s
user 0m0.132s
sys 0m0.060s
```
Another possibility will be to add a `DoubleEndedIterator::next_two_side()` with a deffault implementation, and specialising it for slices, and use it here (`MutableSlice::reverse()` can then become safe). This benchmark will then be safe.
What do you think?
This improves the spectralnorm shootout benchmark through a few vectors after
looking at the leading C implementation:
* The simd-based f64x2 is now used to parallelize a few computations
* RWLock usage has been removed. A custom `parallel` function was added as a
form of stack-based fork-join parallelism. I found that the contention on the
locks was high as well as hindering other optimizations.
This does, however, introduce one `unsafe` block into the benchmarks, which
previously had none.
In terms of timings, the before and after numbers are:
```
$ time ./shootout-spectralnorm-before
./shootout-spectralnorm-before 2.07s user 0.71s system 324% cpu 0.857 total
$ time ./shootout-spectralnorm-before 5500
./shootout-spectralnorm-before 5500 11.88s user 1.13s system 459% cpu 2.830 total
$ time ./shootout-spectralnorm-after
./shootout-spectralnorm-after 0.58s user 0.01s system 280% cpu 0.210 tota
$ time ./shootout-spectralnorm-after 5500
./shootout-spectralnorm-after 5500 3.55s user 0.01s system 455% cpu 0.783 total
```
AsciiStr::to_lower is now AsciiStr::to_lowercase and AsciiStr::to_upper is AsciiStr::to_uppercase to match Ascii trait.
Part of issue #17790.
This is my first pull request so let me know if anything is incorrect.
Thanks!
[breaking-changes]
librustc: Improve method autoderef/deref/index behavior more, and enable IndexMut on mutable vectors.
This fixes a bug whereby the mutability fixups for method behavior were
not kicking in after autoderef failed to happen at any level. It also
adds support for `Index` to the fixer-upper.
Closes#12825.
r? @pnkfelix
Previously it had some uninituitive conditionals due to the interaction
with the Rand construction and Clone reinitialisation to create
sequential identifying numbers. This replaces all that with just
constructing the DropCounters with the appropriate identifiers.
`IndexMut` on mutable vectors.
This fixes a bug whereby the mutability fixups for method behavior were
not kicking in after autoderef failed to happen at any level. It also
adds support for `Index` to the fixer-upper.
Closes#12825.
Previously it had some uninituitive conditionals due to the interaction
with the Rand construction and Clone reinitialisation to create
sequential identifying numbers. This replaces all that with just
constructing the DropCounters with the appropriate identifiers.
