Simplify checked_duration_since
This follows the same design as we updated to in #56490. Internally, all the system specific time implementations are checked, no panics. Then the panicking publicly exported API can just call the checked version of itself and make do with a single panic (`expect`) at the top.
Since the internal sys implementations are now checked, this gets rid of the extra `if self >= &earlier` check in `checked_duration_since`. Except likely making the generated machine code simpler, it also reduces the algorithm from "Check panic condition -> call possibly panicking method" to just "call non panicking method".
Added two test cases:
* Edge case: Make sure `checked_duration_since` on two equal `Instant`s produce a zero duration, not a `None`.
* Most common/intended usage: Make sure `later.checked_duration_since(earlier)`, returns an expected value.
Demo `FromIterator` short-circuiting
while looking at a FIXME in `FromIterator for Option` and `FromIterator for Result`, I realized that the current documentation does not have example code showing exactly what is meant by "no further elements are taken."
The code snippets provided here are meant to correct that.
Update build instructions in README.md
Add additional instructions when `sudo ./x.py install` fails to
complete the build.
This resolves issues #40108 and #49269.
r? @steveklabnik
Provide suggestion when using field access instead of path
When trying to access an associated constant as if it were a field of
an instance, provide a suggestion for the correct syntax.
Fix#57316.
SGX target: fix std unit tests
This fixes some tests and some code in the SGX sys implementation to make the `std` unit test suite pass.
#59009 must be merged first.
This writes an extra `dist/image-$image.txt` which contains the S3 URL
of the cached image and the `sha256` digest of the docker entry point.
This will be uploaded with the rest of the deployed artifacts in the
Travis `after_success` script.
filter suggestions from extern prelude
Fixes#59027.
Modifies the candidate gathering code to call `filter_fn` on extern crates, which causes them to be filtered out when looking for a type.
This changes removes a cyclic dependency between the "test" and "libtest"
crates, where "libtest" depends on "test" for "black_box", but "test" depends on
"libtest" for everything else.
I've chosen the "hint" module because there seems to be enough consensus in the
discussion of RFC2360 that this module is where such an intrinsic would belong,
but this PR does not implement that RFC! (note: if that RFC ever gets merged,
the API, docs, etc. of this API will need to change).
For backwards compatibility reasons I've chosen to also keep the "test" feature
gate for these instead of adding a new feature gate. If we change the feature
gate, we'll potentially all benchmarks, and while that's something that we could
do, it seems unnecessary to do that now - if RFC2360 gets merged, we'll need to
do that anyways.
make asm diagnostic instruction optional
`DiagnosticInfoInlineAsm::getInstruction` may return a null pointer, so
the instruction shouldn't be blindly unwrapped.
Reopening from #55193. I was unable to trigger the assertion on Windows after rebasing.
Fixes#23458.
Fixes#55216.
When moving out of a for loop head, suggest borrowing it
When encountering code like the following, suggest borrowing the for loop
head to avoid moving it into the for loop pattern:
```
fn main() {
let a = vec![1, 2, 3];
for i in &a {
for j in a {
println!("{} * {} = {}", i, j, i * j);
}
}
}
```
Fix#25534.
