Remove the `overlapping_marker_traits` feature
See #29864
This has been replaced by `#[feature(marker_trait_attr)]`
A few notes:
* Due to PR #68057 not yet being in the bootstrap compiler, it's
necessary to continue using `#![feature(overlapping_marker_traits)]`
under `#[cfg(bootstrap)]` to work around type inference issues.
* I've updated tests that used `overlapping_marker_traits` to now use
`marker_trait_attr` where applicable
The test `src/test/ui/overlap-marker-trait.rs` doesn't make any sense
now that `overlapping_marker_traits`, so I removed it.
The test `src/test/ui/traits/overlap-permitted-for-marker-traits-neg.rs`
now fails, since it's no longer possible to have multiple overlapping
negative impls of `Send`. I believe that this is the behavior we want
(assuming that `Send` is not going to become a `#[marker]` trait, so I
renamed the test to `overlap-permitted-for-marker-traits-neg`
fix couple of perf related clippy warnings
librustc: don't clone a type that is copy
librustc_incremental: use faster vector initialization
librustc_typeck: don't clone a type that is copy
librustdoc: don't create a vector where a slice will do
Fix 59191 - ICE when macro replaces crate root with non-module item
Hi,
This should fix#59191! My friend and I are working on learning the rustc codebase through contributions, so please feel free to mention anything amiss or that could be done better.
The code adds an explicit case for when a macro applied to the crate root (via an inner attribute) replaces it with something nonsensical, like a function. The crate root must be a module, and the error message reflects this.
---
I should note that there are a few other weird edge cases here, like if they do output a module, it succeeds but uses that module's name as a prefix for all names in the crate. I'm assuming that's an issue for stabilizing #54726, though.
Instrument C / C++ in MemorySanitizer example
Modify the example to instrument C / C++ in addition to Rust, since it
will be generally required (e.g., when using libbacktrace for symbolication).
Add a method to query the capacity of a BufWriter and BufReader
Besides the obvious of retrieving the parameter used to construct the writer, this method allows consumers to control the number of `flush` calls during write operations. For `BufReader` it gives an upper bound on the returned buffer in `fill_buf` which might influence the allocation behaviour of a consumer.
