r? @steveklabnik
Currently neither the API docs nor the book clearly explain that out-of-bounds array indexing causes a panic. Since this is fairly important and seems to surprise a number of new Rust programmers, I think it's worth adding to both places. (But if you think it would be better to put this info in the API docs only, that's fine too.)
Some specific things I'd like feedback on:
* The new text here talks about panicking, which hasn't been formally introduced at this point in chapter 5 (though it has been mentioned in previous sections too).
* Similarly the `Vec::get` example uses `Option<T>` which hasn't been fully introduced yet. Should we leave out this example?
The landing of #30182, specifically the removal of float `from_str_radix`, allowed the refactoring in the middle commit. While I was at it, I also crossed two other nits off my TODO list.
Turns out that calling `resolve_type_variables_if_possible` in a O(n^2)
loop is a bad idea. Now we just resolve each copy of the region variable
to its lowest name each time (we resolve the region variable to its lowest
name, rather than to its unify-table name to avoid the risk of
the unify-table name changing infinitely many times. That may be
not a problem in practice, but I am not sure of it).
Fixes#29844
I would prefer to
(a) make some performance measurements
(b) use the unification table in a few more places
before committing further, but this is probably good enough for beta.
r? @nikomatsakis
The import has been unnecessarily complicated since ParseFloatError::Invalid is not longer used unqualified.
The pfe_* functions do not need to be public any more since the only other use site, from_str_radix for floats, has been removed.
r? @nagisa
I'm going to need the `ConstVal` -> `ValueRef` translation to start removing trans/consts piece by piece. If you need anything implemented in the translation, feel free to assign an issue to me.
Running `/usr/bin/time -v make` to build rust (using local llvm) shows the maximum memory usage at 715 megabytes on 32-bit x86 (on arm linux it's even less @ 580M).
Reworded according to @brson's [input](https://github.com/rust-lang/rust/pull/30196#issuecomment-162088921).
This fixes a bug in which the visibility of a use declaration defining a name in one namespace (e.g. the value namespace) is overridden by a later use declaration defining the same name in the other namespace (e.g. the type namespace). For example,
```rust
fn f() {}
pub mod bar {}
mod foo {
use f; // This import should not be visible outside `foo`,
pub use bar as f; // but it visible outside of `foo` because of this import.
}
fn main() { foo::f(); }
```
As the example demonstrates, this is a [breaking-change], but it looks unlikely to cause breakage in practice, and any breakage can be fixed by correcting visibility modifiers.
This PR makes `Mir` `RustcEncodable` and `RustcDecodable` and stores it in crate metadata for inlinable items.
Some other things in here:
- `mir::visit::Visitor` is extended to also visit `Literals`, `Spans` and `DefIds`.
- It also adds `mir::visit::MutVisitor` which allows to mutate the visited `Mir` structure in place.
- Some numbers on how big MIR is in metadata (total metadata size in bytes):
| | w/ MIR | w/o MIR | Rel. Size |
|----------------|-----------:|------------:|:---------:|
| libcore | 17,695,473 | 14,263,377 | 124% |
| liblibc | 411,440 | 404,382 | 102% |
| libcollections | 4,537,975 | 3,526,933 | 129% |
| libserialize | 2,574,769 | 2,060,798 | 125% |
| libsyntax | 15,262,894 | 12,075,574 | 126% |
| librustc | 16,984,537 | 13,692,168 | 124% |
So, adding MIR to metadata makes it about 25% bigger. It could be worse, considering that it still uses the inefficient RBML encoding. Still, the question is whether we should put MIR emission behind a `-Z` flag.
This changes the error output and behaviour to:
* not emit python backtraces
* run all checks
* include a context line per error
* move the offending line-number to the start of the line
fixes#21455
This is a standard "clean out libstd" commit which removes all 1.5-and-before
deprecated functionality as it's now all been deprecated for at least one entire
cycle.
