incr.comp.: Verify stability of incr. comp. hashes and clean up various other things.
The main contribution of this PR is that it adds the `-Z incremental-verify-ich` functionality. Normally, when the red-green tracking system determines that a certain query result has not changed, it does not re-compute the incr. comp. hash (ICH) for that query result because that hash is already known. `-Z incremental-verify-ich` tells the compiler to re-hash the query result and compare the new hash against the cached hash. This is a rather thorough way of
- testing hashing implementation stability,
- finding missing `[input]` annotations on `DepNodes`, and
- finding missing read-edges,
since both a missed read and a missing `[input]` annotation can lead to something being marked as green instead of red and thus will have a different hash than it should have.
Case in point, implementing this verification logic and activating it for all `src/test/incremental` tests has revealed several such oversights, all of which are fixed in this PR.
r? @nikomatsakis
I'm really new to Rust, this is the first thing I've ever actually pushed to github in a rust project, so please double check that it's correct. I noticed that the in-doc example for the string's get() function was referring to get_mut(). Looks like a copy/paste issue.
```rust
fn main() {
let v = String::from("🗻∈🌏");
assert_eq!(Some("🗻"), v.get(0..4));
// indices not on UTF-8 sequence boundaries
assert!(v.get(1..).is_none());
assert!(v.get(..8).is_none());
// out of bounds
assert!(v.get(..42).is_none());
}
```
results in:
```
jhford-work:~/rust/redish $ cat get-example.rs
fn main() {
let v = String::from("🗻∈🌏");
assert_eq!(Some("🗻"), v.get(0..4));
// indices not on UTF-8 sequence boundaries
assert!(v.get(1..).is_none());
assert!(v.get(..8).is_none());
// out of bounds
assert!(v.get(..42).is_none());
}
jhford-work:~/rust/redish $ rustc get-example.rs
jhford-work:~/rust/redish $ ./get-example ; echo $?
0
```
I did not build an entire rust toolchain as I'm not totally sure how to do that.
put the error message on one line so the test suite does not think it is two errors
use a substring of the error message so it fits in 100 chars for tidy
Detect `=` -> `:` typo in let bindings
When encountering a let binding type error, attempt to parse as
initializer instead. If successful, it is likely just a typo:
```rust
fn main() {
let x: Vec::with_capacity(10);
}
```
```
error: expected type, found `10`
--> file.rs:3:31
|
3 | let x: Vec::with_capacity(10, 20);
| -- ^^
| ||
| |help: did you mean assign here?: `=`
| while parsing the type for `x`
```
Fix#43703.
On the case of duplicated names caused by an `extern crate` statement
with a rename, don't include the inline suggestion, instead using a span
label with only the text to avoid incorrect rust code output.
Saturating casts between integers and floats
Introduces a new flag, `-Z saturating-float-casts`, which makes code generation for int->float and float->int casts safe (`undef`-free), implementing [the saturating semantics laid out by](https://github.com/rust-lang/rust/issues/10184#issuecomment-299229143) @jorendorff for float->int casts and overflowing to infinity for `u128::MAX` -> `f32`.
Constant evaluation in trans was changed to behave like HIR const eval already did, i.e., saturate for u128->f32 and report an error for problematic float->int casts.
Many thanks to @eddyb, whose APFloat port simplified many parts of this patch, and made HIR constant evaluation recognize dangerous float casts as mentioned above.
Also thanks to @ActuallyaDeviloper whose branchless implementation served as inspiration for this implementation.
cc #10184#41799fixes#45134
Disable `mmap` in `libbacktrace` on Apple platforms
Fixes#45731
libbacktrace uses mmap if available to map ranges of the files containing debug information. On macOS `mmap` will succeed even if the mapped range does not exist, and a SIGBUS (with an unusual EXC_BAD_ACCESS code 10) will occur when the program attempts to page in the memory. To combat this we force `libbacktrace` to be built with the simple `read` based fallback on Apple platforms.
I doubt this changes anything, I was just trying to fix an issue with
error messages and ended up doing this along with other things.
Committing it separately so I can undo it easily.
Only instantiate inline- and const-fns if they are referenced (again).
It seems that we have regressed on not translating `#[inline]` functions unless they are actually used. This should bring back this optimization. I also added a regression test this time so it doesn't happen again accidentally.
Fixes#40392.
r? @alexcrichton
UPDATE & PSA
---------------------
This patch **makes translation very lazy** -- in general this is a good thing (we don't want the compiler to do unnecessary work) but it has two consequences:
1. Some error messages are only generated when an item is actually translated. Consequently, this patch will lead to more cases where the compiler will only start emitting errors when the erroneous function is actually used. This has always been true to some extend (e.g. when passing generic values to an intrinsic) but since this is something user-facing it's worth mentioning.
2. When writing tests, one has to make sure that the functions in question are actually generated. In other words, it must not be dead code. This can usually be achieved by either
1. making sure the function is exported from the resulting binary or
2. by making sure the function is called from something that is exported (or `main()`).
Note that it depends on the crate type what functions are exported:
1. For rlibs and dylibs everything that is reachable from the outside is exported.
2. For executables, cdylibs, and staticlibs, items are only exported if they are additionally `#[no_mangle]` or have an `#[export_name]`.
The commits in this PR contain many examples of how tests can be updated to comply to the new requirements.
Fixes#45731
libbacktrace uses mmap if available to map ranges of the files containing debug information. On macOS `mmap` will succeed even if the mapped range does not exist, and a SIGBUS (with an unusual EXC_BAD_ACCESS code 10) will occur when the program attempts to page in the memory. To combat this we force `libbacktrace` to be built with the simple `read` based fallback on Apple platforms.
Warn about lack of args glob expansion in Windows shell
Because all shells on Linux/macOS expand globs, and even MinGW on Windows emulates this behavior, it's easy to forget that Windows by itself doesn't support glob expansion. This PR documents this cross-platform difference.
impl FromIterator<()> for ()
This just collapses all unit items from an iterator into one. This is
more useful when combined with higher-level abstractions, like
collecting to a `Result<(), E>` where you only care about errors:
```rust
use std::io::*;
data = vec![1, 2, 3, 4, 5];
let res: Result<()> = data.iter()
.map(|x| writeln!(stdout(), "{}", x))
.collect();
assert!(res.is_ok());
```
Remove `T: Sized` on pointer `as_ref()` and `as_mut()`
`NonZero::is_zero()` was already casting all pointers to thin `*mut u8` to check for null. The same test on unsized fat pointers can also be used with `as_ref()` and `as_mut()` to get fat references.
(This PR formerly changed `is_null()` too, but checking just the data pointer is not obviously correct for trait objects, especially if `*const self` sorts of methods are ever allowed.)
