This wasn't marked inline, so wasn't being inlined cross-crate. It's
actually a no-op function, since it's a wrapper around `mem::transmute`.
Marking it inline means that programs calling it can see that it's a
no-op and act accordingly during optimisation.
The statement is not completely exact, because it is valid to have
both 0 non-mutable references and 1 mutable reference. Instead, use
the same wording as in mutability.md.
Hi
I added a little section in the for loops about the `enumerate()` function.
I think it's useful for beginners to know this function and how you can use it.
I used the title loopcounter, but it's probably not the best word to describe it. So let me know if there is a better word :)
This wasn't marked inline, so wasn't being inlined cross-crate. It's
actually a no-op function, since it's a wrapper around `mem::transmute`.
Marking it inline means that programs calling it can see that it's a
no-op and act accordingly during optimisation.
The statement is not completely exact, because it is valid to have
both 0 non-mutable references and 1 mutable reference. Instead, use
the same wording as in mutability.md.
Issue: https://github.com/rust-lang/rust/issues/25969
Compare the span on the stable branch (correct) with the span on the nightly branch (incorrect) for the following example: http://is.gd/lTAo9c. This pull request fixes the regression.
@Manishearth has been kind enough to pitch some ideas for a regression test, mainly revolving around testing the span in compile-fail test, but this has proven unsuccessful. Other suggestions/ ideas would be much appreciated!
The API documentation is not explicit enough that because `try!` returns
`Err` early for you, you can only use it in functions that return
`Result`. The book mentions this, but if you come across `try!` outside
of the book and look it up in the docs, this restriction on the return
type of the function is not particularly clear.
I seriously had this epiphany a few days ago after working with Rust for MONTHS, and after seeing [a friend have to come to the same realization](http://joelmccracken.github.io/entries/a-simple-web-app-in-rust-pt-2a/), I'd like to save more people from this confusion :) 💖
Fix the dropck doc formatting to avoid hitting four-space indent.
This was causing `rustdoc` to interpret the part starting with `(A.) ...` as a code block based on its four-space indentation, which then was treated by `rustdoc` as a *Rust* code snippet, and thus was attempting (and failing) to parse my english as Rust code. Thus causing the compiler-docs build to fail.
Independently, we should probably change `rustdoc` to not interpret four-space indents as code that needs to be tested; it seems too perilous to me at least.
(But the formatting here needed to be changed either way.)
cc Issue #25699.
My main sources of information are [RFC401](https://github.com/rust-lang/rfcs/blob/master/text/0401-coercions.md), the rust IRC channel, and a bunch of experiments to figure out what `rustc` currently supports.
Note that the RFC calls for some coercion behaviour that is not implemented yet (see #18469).
The documentation in this PR mostly covers current behaviour of rust and doesn't document the future behaviour. I haven't written about receiver expression coercion.
I would be happy to rewrite/adapt the PR according to feedback.
r? @steveklabnik
Part of #24407.
Currently the diagnostics for range patterns are a bit wrong:
```rust
fn main() {
match 5u32 {
0 ... 10 => (),
'a' ... 10 => (),
10 ... 'z' => (),
"what" ... 10 => (),
"what" ... "well" => (),
10 ... "what" => ()
}
}
```
```
range.rs:4:9: 4:19 error: mismatched types in range:
expected integral variable,
found char [E0211]
range.rs:4 'a' ... 10 => (),
^~~~~~~~~~
range.rs:4:9: 4:16 error: only char and numeric types are allowed in range [E0029]
range.rs:4 'a' ... 10 => (),
^~~~~~~
range.rs:4:9: 4:19 error: mismatched types:
expected `u32`,
found `char`
(expected u32,
found char) [E0308]
range.rs:4 'a' ... 10 => (),
^~~~~~~~~~
range.rs:5:9: 5:19 error: mismatched types in range:
expected char,
found integral variable [E0211]
range.rs:5 10 ... 'z' => (),
^~~~~~~~~~
range.rs:5:9: 5:15 error: only char and numeric types are allowed in range [E0029]
range.rs:5 10 ... 'z' => (),
^~~~~~
range.rs:6:9: 6:22 error: mismatched types in range:
expected integral variable,
found &-ptr [E0211]
range.rs:6 "what" ... 10 => (),
^~~~~~~~~~~~~
range.rs:6:9: 6:19 error: only char and numeric types are allowed in range [E0029]
range.rs:6 "what" ... 10 => (),
^~~~~~~~~~
range.rs:6:9: 6:22 error: mismatched types:
expected `u32`,
found `&'static str`
(expected u32,
found &-ptr) [E0308]
range.rs:6 "what" ... 10 => (),
^~~~~~~~~~~~~
range.rs:7:9: 7:19 error: only char and numeric types are allowed in range [E0029]
range.rs:7 "what" ... "well" => (),
^~~~~~~~~~
range.rs:7:9: 7:26 error: mismatched types:
expected `u32`,
found `&'static str`
(expected u32,
found &-ptr) [E0308]
range.rs:7 "what" ... "well" => (),
^~~~~~~~~~~~~~~~~
range.rs:8:9: 8:22 error: mismatched types in range:
expected &-ptr,
found integral variable [E0211]
range.rs:8 10 ... "what" => ()
^~~~~~~~~~~~~
range.rs:8:9: 8:15 error: only char and numeric types are allowed in range [E0029]
range.rs:8 10 ... "what" => ()
^~~~~~
error: aborting due to 12 previous errors
```
The problems here are:
1. The type of the end of the range is used to predict the type of the start (only mildly counter intuitive).
2. E0029 is erroneously generated for `char ... num` and `num ... char`.
2. `u32` is mentioned.
3. Errors which are essentially the same are reported multiple times.
I've attempted to fix this by checking the requirements in a different order. The output I've achieved for the above example is:
```
/home/michael/Temp/range.rs:4:17: 4:22 error: mismatched types in range:
expected char,
found integral variable [E0211]
/home/michael/Temp/range.rs:4 'a' ... 10 => (),
^~~~~
/home/michael/Temp/range.rs:5:16: 5:22 error: mismatched types in range:
expected integral variable,
found char [E0211]
/home/michael/Temp/range.rs:5 10 ... 'z' => (),
^~~~~~
/home/michael/Temp/range.rs:6:9: 6:19 error: only char and numeric types are allowed in range [E0029]
/home/michael/Temp/range.rs:6 "what" ... 10 => (),
^~~~~~~~~~
/home/michael/Temp/range.rs:6:9: 6:19 help: run `rustc --explain E0029` to see a detailed explanation
/home/michael/Temp/range.rs:6:9: 6:19 note: Start type: &'static str
End type: _
/home/michael/Temp/range.rs:6 "what" ... 10 => (),
^~~~~~~~~~
/home/michael/Temp/range.rs:7:9: 7:26 error: only char and numeric types are allowed in range [E0029]
/home/michael/Temp/range.rs:7 "what" ... "well" => (),
^~~~~~~~~~~~~~~~~
/home/michael/Temp/range.rs:7:9: 7:26 help: run `rustc --explain E0029` to see a detailed explanation
/home/michael/Temp/range.rs:7:9: 7:26 note: Start type: &'static str
End type: &'static str
/home/michael/Temp/range.rs:7 "what" ... "well" => (),
^~~~~~~~~~~~~~~~~
/home/michael/Temp/range.rs:8:16: 8:25 error: only char and numeric types are allowed in range [E0029]
/home/michael/Temp/range.rs:8 10 ... "what" => ()
^~~~~~~~~
/home/michael/Temp/range.rs:8:16: 8:25 help: run `rustc --explain E0029` to see a detailed explanation
/home/michael/Temp/range.rs:8:16: 8:25 note: Start type: _
End type: &'static str
/home/michael/Temp/range.rs:8 10 ... "what" => ()
^~~~~~~~~
error: aborting due to 5 previous errors
```
I think this is already tonnes better, but the `Start type/End type` stuff could be neater. I don't think there's really any need to start a `note:` block but I wanted to get some feedback on this. I'd also appreciate advice on how to print the integer types as something other than `_`.
Hack the move_val_init intrinsic to trans directly into the destination address.
This is to remove an intermediate (and unnecessary) alloca on the stack that one otherwise suffers when using this intrinsic.
This is part of the `box` protocol work; in particular, this is meant to address the `ptr::write` codegen issues alluded to at this comment:
https://github.com/rust-lang/rust/pull/22086#issuecomment-96168675
cc #22181
This was always a weird feature, and isn't being used in the compiler.
Static assertions should be done better than this.
Fixes#13951Fixes#23008Fixes#6676
This is behind a feature gate, but that's still a
[breaking-change]
(It's not entirely clear to me that this should or shouldn't have an RFC, but if it does, I'm fine blocking on such a thing.)
