Every codegen unit gets its own local counter for generating new symbol
names. This makes bitcode and object files reproducible at the binary
level even when incremental compilation is used.
Motivation: the `selectors` crate is generic over a string type,
in order to support all of `String`, `string_cache::Atom`, and
`gecko_string_cache::Atom`. Multiple trait bounds are used
for the various operations done with these strings.
One of these operations is creating a string (as efficiently as possible,
re-using an existing memory allocation if possible) from `Cow<str>`.
The `std::convert::From` trait seems natural for this, but
the relevant implementation was missing before this PR.
To work around this I’ve added a `FromCowStr` trait in `selectors`,
but with trait coherence that means one of `selectors` or `string_cache`
needs to depend on the other to implement this trait.
Using a trait from `std` would solve this.
The `Vec<T>` implementation is just added for consistency.
I also tried a more general
`impl<'a, O, B: ?Sized + ToOwned<Owned=O>> From<Cow<'a, B>> for O`,
but (the compiler thinks?) it conflicts with `From<T> for T` the impl
(after moving all of `collections::borrow` into `core::borrow`
to work around trait coherence).
syntax: Tweak path parsing logic
Associated paths starting with `<<` are parsed in patterns.
Paths like `self::foo::bar` are interpreted as paths and not as `self` arguments in methods (cc @matklad).
Now, I believe, *all* paths are consistently parsed greedily in case of ambiguity.
Detection of `&'a mut self::` requires pretty large (but still fixed) lookahead, so I had to increase the size of parser's lookahead buffer.
Curiously, if `lookahead_distance >= lookahead_buffer_size` was used previously, the parser hung forever, I fixed this as well, now it ICEs.
r? @jseyfried
macros: Future proof `#[no_link]`
This PR future proofs `#[no_link]` for macro modularization (cc #35896).
First, we resolve all `#[no_link] extern crate`s. `#[no_link]` crates without `#[macro_use]` or `#[macro_reexport]` are not resolved today, this is a [breaking-change]. For example,
```rust
```
Any breakage can be fixed by simply removing the `#[no_link] extern crate`.
Second, `#[no_link] extern crate`s will define an empty module in type namespace to eventually allow importing the crate's macros with `use`. This is a [breaking-change], for example:
```rust
mod syntax {} //< This becomes a duplicate error.
```
r? @nrc
Enable line number debuginfo in releases
This commit enables by default passing the `-C debuginfo=1` argument to the
compiler for the stable, beta, and nightly release channels. A new configure
option was also added, `--enable-debuginfo-lines`, to enable this behavior in
developer builds as well.
Closes#36452
Attribute drop code to block's closing brace, instead of the line where the allocation was done.
Attribute function epilogues to function body's closing brace, rather than the function header.
Detect local-rebuild by just the MAJOR.MINOR version
A new point-release shouldn't change any language semantics, so a local
stage0 that matches MAJOR.MINOR version should still be considered a
local-rebuild as far as `--cfg stageN` features go.
e.g. `1.14.0` should be considered a local-rebuild for any `1.14.X`.
(Bootstrap keys used to be an issue too, until #37265.)
