The default capacity of a VecDeque is 8, which is excessive here. In a
"base incremental" check build of rustc-perf's tuple-stress benchmark,
this decreases total heap allocation by 26%. I couldn't see a clear
speedup, but it can't hurt.
Filter global bounds from ParamEnv again.
This PR adds back the filtering of global bounds from ParamEnv as a temporary solution for #50825.
<details>
Long term, the fix seems like it should be changing the priority in `candidate_should_be_dropped_in_favor_of` so that (global) where clauses aren't considered as highly.
a722296b6e/src/librustc/traits/select.rs (L2017-L2022)
</details>
r? @nikomatsakis
rustc: Fix joint-ness of stringified token-streams
This commit fixes `StringReader`'s parsing of tokens which have been stringified
through procedural macros. Whether or not a token tree is joint is defined by
span information, but when working with procedural macros these spans are often
dummy and/or overridden which means that they end up considering all operators
joint if they can!
The fix here is to track the raw source span as opposed to the overridden span.
With this information we can more accurately classify `Punct` structs as either
joint or not.
Closes#50700
Escape combining characters in char::Debug
Although combining characters are technically printable, they make little sense to print on their own with `Debug`: it'd be better to escape them like non-printable characters.
This is a breaking change, but I imagine the fact `escape_debug` is rare and almost certainly primarily used for debugging that this is an acceptable change.
Resolves#41922.
r? @alexcrichton
cc @clarcharr
Fix issue #50811 (`NaN > NaN` was true).
Fix#50811
Make sure the float comparison output is consistent with the expected behavior when NaN is involved.
----
Note: This PR is a **BREAKING CHANGE**. If you have used `>` or `>=` to compare floats, and make the result as the length of a fixed array type, like:
```rust
use std::f64::NAN;
let x: [u8; (NAN > NAN) as usize] = [1];
```
then the code will no longer compile. Previously, all float comparison involving NaN will just return "Greater", i.e. `NAN > NAN` would wrongly return `true` during const evaluation. If you need to retain the old behavior (why), you may replace `a > b` with `a != a || b != b || a > b`.
