Simplify the macro hygiene algorithm
This PR removes renaming from the hygiene algorithm and treats differently marked identifiers as unequal.
This change makes the scope of identifiers in `macro_rules!` items empty. That is, identifiers in `macro_rules!` definitions do not inherit any semantics from the `macro_rules!`'s scope.
Since `macro_rules!` macros are items, the scope of their identifiers "should" be the same as that of other items; in particular, the scope should contain only items. Since all items are unhygienic today, this would mean the scope should be empty.
However, the scope of an identifier in a `macro_rules!` statement today is the scope that the identifier would have if it replaced the `macro_rules!` (excluding anything unhygienic, i.e. locals only).
To continue to support this, this PR tracks the scope of each `macro_rules!` and uses it in `resolve` to ensure that an identifier expanded from a `macro_rules!` gets a chance to resolve to the locals in the `macro_rules!`'s scope.
This PR is a pure refactoring. After this PR,
- `syntax::ext::expand` is much simpler.
- We can expand macros in any order without causing problems for hygiene (needed for macro modularization).
- We can deprecate or remove today's `macro_rules!` scope easily.
- Expansion performance improves by 25%, post-expansion memory usage decreases by ~5%.
- Expanding a block is no longer quadratic in the number of `let` statements (fixes#10607).
r? @nrc
doc: ffi referenced rust-snappy can not compile
r? @steveklabnik
The referenced code https://github.com/thestinger/rust-snappy can not work. Maybe it's the old rust version? I do not know.
So I try to rewrite these test cases. If it is not what you originally meaning, just ignored it.
doc: Mention that writeln! and println! always use LF
Fixes#34697
I'm not really satisfied with the wording, but I didn't have a better idea. Suggestions welcome.
Improve arc doc, fixing #32905
As issue #32905 detailed, I moved part of the module doc to the struct doc, and fixed some small places in the `alloc::arc`.
rustbuild: doc fixes
This fixes two issues rustbuild currently has when building documentation:
1. It fixes standalone builds of `doc-test` and `doc-rustc`.
2. It actually builds the compiler docs if requested in the config.
Closes#34275.
Fixed issue where importing a trait method directly and then calling the method causes a compiler panic
The code below triggers the panic, and is included in a new regression test.
```rust
trait Foo {
fn foo();
}
use Foo::foo;
fn main() {
foo();
}
```
The bug is caused by `librustc_resolve` allowing the illegal binding to be imported even after displaying the error message above.
The fix amounts to importing a dummy binding (`rustc::hir::def::Def::Err`) instead of the actual trait method.
test: Remove NOTE assertions from trace_macros-gate
If no NOTE assertions are present I believe they aren't asserted at all, and it
looks like the number of NOTEs differs on distcheck vs `make check`, so let's
just remove them all.
Closes#18154
If no NOTE assertions are present I believe they aren't asserted at all, and it
looks like the number of NOTEs differs on distcheck vs `make check`, so let's
just remove them all.
Closes#18154
Mention the crate type cdylib in rustc's usage
Hello,
I just tried to build a `cdylib` with the latest stable release, I've been passively waiting for this for quite some time now. Tested successfully on my machine, although it doesn't appear in `rustc`'s usage it seems to work like a charm so far. 😀
Thanks!
std: fix `readdir` errors for solaris
A `NULL` from `readdir` could be the end of stream or an error. The only
way to know is to check `errno`, so it must be set to a known value first,
like a 0 that POSIX will never use.
This currently only matters for solaris targets, as the other unix platforms
are using `readdir_r` with a direct error return indication. However, this is
getting deprecated (#34668) so they should all eventually switch to `readdir`.
This PR adds `set_errno`, uses it to clear the value before calling `readdir`,
then checks it again after to see the reason for a `NULL`. A few other small
fixes are included just to get solaris compiling at all.
I couldn't get cross-compilation completely going, so I don't have a good way
to test this beyond a smoke-test cargo build of std. I'd appreciate input from
someone more familiar with solaris -- cc @nbaksalyar?
