Add AST validation pass and move some checks to it
The purpose of this pass is to catch constructions that fit into AST data structures, but not permitted by the language. As an example, `impl`s don't have visibilities, but for convenience and uniformity with other items they are represented with a structure `Item` which has `Visibility` field.
This pass is intended to run after expansion of macros and syntax extensions (and before lowering to HIR), so it can catch erroneous constructions that were generated by them. This pass allows to remove ad hoc semantic checks from the parser, which can be overruled by syntax extensions and occasionally macros.
The checks can be put here if they are simple, local, don't require results of any complex analysis like name resolution or type checking and maybe don't logically fall into other passes. I expect most of errors generated by this pass to be non-fatal and allowing the compilation to proceed.
I intend to move some more checks to this pass later and maybe extend it with new checks, like, for example, identifier validity. Given that syntax extensions are going to be stabilized in the measurable future, it's important that they would not be able to subvert usual language rules.
In this patch I've added two new checks - a check for labels named `'static` and a check for lifetimes and labels named `'_`. The first one gives a hard error, the second one - a future compatibility warning.
Fixes https://github.com/rust-lang/rust/issues/33059 ([breaking-change])
cc https://github.com/rust-lang/rfcs/pull/1177
r? @nrc
stable features lint warning mentions version stabilized
To accomplish this, we alter the checks in `rustc::middle::stability` to
use the `StabilityLevel` defined in `syntax::attr` (which includes the
version in which the feature was stabilized) rather than the local
`StabilityLevel` in the same module, and make the
`declared_stable_lang_features` field of
`syntax::feature_gate::Features` hold a Vec of feature-name, span
tuples (in analogy to the `declared_lib_features` field) rather than
just spans.
Fixes#33394.
r? @brson (tagging Brian because he [wrote](https://github.com/rust-lang/rust/pull/21958) the lint)
resolve: record pattern def when `resolve_pattern` returns `Err(true)`
I propose a fix for issue #33293.
In 1a374b8, (pr #33046) fixed the error reporting of a specific case, but the change that was introduced did not make sure that `record_def` was called in all cases, which lead to an ICE in [1].
This change restores the original `else` case, but keeps the changes that were committed in 1a374b8.
[1] `rustc::middle::mem_categorization::MemCategorizationContext::cat_pattern_`
Inline simple Cursor write calls
Implementing the Write trait for Cursors over slices is so light-weight that under some circumstances multiple writes can be fused into a single instruction. In general I think inlining these functions is a good idea because most of the code can be constant-folded and copy-propagated away.
Closes issue #33916.
r? @alexcrichton
core: check pointer equality when comparing byte slices
If pointer address and length are the same, it should be the same slice.
In experiments, I've seen that this doesn't happen as often in debug builds, but release builds seem to optimize to using a single pointer more often.
Reject a LHS formed of a single sequence TT during `macro_rules!` checking.
This was already rejected during expansion. Encountering malformed LHS or RHS during expansion is now considered a bug.
Follow up to #33689.
r? @pnkfelix
Note: this can break code that defines such macros but does not use them.
Attempt to diagnose #33844https://github.com/rust-lang/rust/issues/33844 is a spurious failure that causes builds to fail due to the linker command sometimes failing with error 206, which means that the command is too long. This PR makes rustc print out the linker arguments in that case so the reason for it being so long can be diagnosed and hopefully fixed.
r? @alexcrichton
mk: Prepare for a new stage0 compiler
This commit prepares the source for a new stage0 compiler, the 1.10.0 beta
compiler. These artifacts are hot off the bots and should be ready to go.
To accomplish this, we alter the checks in `rustc::middle::stability` to
use the `StabilityLevel` defined in `syntax::attr` (which includes the
version in which the feature was stabilized) rather than the local
`StabilityLevel` in the same module, and make the
`declared_stable_lang_features` field of
`syntax::feature_gate::Features` hold a Vec of feature-name, span
tuples (in analogy to the `declared_lib_features` field) rather than
just spans.
This is in the matter of issue #33394.
In 1a374b8, (pr #33046) fixed the error reporting of a specific
case, but the change that was introduced did not make sure that
`record_def` was called in all cases, which lead to an ICE in [1].
This change restores the original `else` case, but keeps the changes
that were committed in 1a374b8.
This commit fixes issue #33293.
[1] `rustc::middle::mem_categorization::MemCategorizationContext::cat_pattern_`
print enum variant fields in docs
Right now we are repeating enum variants at the top, because the fields aren't shown with the actual docs. It's very annoying to have to scroll up and down to have both docs and field info. For struct variants we already list the fields.
enum docs look like this after this PR:
There are degenerate cases for enum tuple variants with lots of fields:
I was thinking that we could move the docs below the variant (slightly indented) or list the variant fields vertically instead of horizontally
r? @steveklabnik
Added examples/docs to split in str.rs
Added documentation clarifying the behavior of split when used with the empty string and contiguous separators. Addresses issue [33882](https://github.com/rust-lang/rust/issues/33882). This is my first time contributing to rust, so forgive me if I'm skipping any of the contribution steps.
Fixes#33882
Separate bindings from other patterns in HIR
Now when name resolution is done on AST, we can avoid dumping everything that looks like an identifier into `PatKind::Ident` in HIR.
`hir::PatKind::Ident` is removed, fresh bindings are now called `hir::PatKind::Binding`, everything else goes to `hir::PatKind::Path`.
I intend to do something with `PatKind::Path`/`PatKind::QPath` as well using resolution results, but it requires some audit and maybe some deeper refactoring of relevant resolution/type checking code to do it properly.
I'm submitting this part of the patch earlier to notify interested parties that I'm working on this.
cc @jseyfried
r? @eddyb
antlr grammar verification script now compiles under latest nightly
This is kind of a moving target, since none of libsyntax is stable, but at least this compiles for the time being.
