When we do a "HR subtype" check, we replace all late-bound regions (LBR)
in the subtype with fresh variables, and skolemize the late-bound
regions in the supertype. If those skolemized regions from the supertype
wind up being super-regions (directly or indirectly) of either
- another skolemized region; or,
- some region that pre-exists the HR subtype check
- e.g., a region variable that is not one of those created
to represent bound regions in the subtype
then the subtype check fails.
What will change when we fix#32330 is that some of the LBR in the
subtype may become early-bound. In that case, they would no longer be in
the "permitted set" of variables that can be related to a skolemized
type.
So the foundation for this warning is to collect variables that we found
to be related to a skolemized type. For each of them, we have a
`BoundRegion` which carries a `Issue32330` flag. We check whether any of
those flags indicate that this variable was created from a lifetime
that will change from late- to early-bound. If so, we issue a warning
indicating that the results of compilation may change.
This is imperfect, since there are other kinds of code that will not
compile once #32330 is fixed. However, it fixes the errors observed in
practice on crater runs.
This indicates whether this `BoundRegion` will change from late to early
bound when issue 32330 is fixed. It also indicates the function on
which the lifetime is declared.
Currently, we consider region subtyping a failure
if a skolemized lifetime is relatable to any
other lifetime in any way at all. But a more precise
formulation is to say that a skolemized lifetime:
- must not have any *incoming* edges in the region graph
- only has *outgoing* edges to nodes that are `'static`
To enforce the latter requirement, we add edges from `'static -> 'x` for
each lifetime '`x' reachable from a skolemized region.
We now have to add a new `pop_skolemized` routine to do cleanup.
Whereas before if there were *any* edges relating to a skolemized
region, we would return `Err` and hence rollback the transaction, we now
tolerate some edges and return `Ok`. Therefore, the `pop_skolemized`
routine runs and cleans up those edges.
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.
save-analysis: be a bit more defensive with field sub-expressions
Prevents an ice with `(...).f` since the sub-expression is in the AST but not the HIR.
We could actually do better in this specific case, but it doesn't seem worth it.
Prevent overflows by increasing ring buffer size
Please note that this change is just done to prevent
issues as currently seen by syntex_syntax in future.
See https://github.com/serde-rs/syntex/pull/47 for details.
As shown in https://github.com/serde-rs/syntex/issues/33,
complex code can easily overflow the ring-buffer and
cause an assertion error.
test: Use `set sysroot` for more NDK compatibility
Recent versions of the Android NDK no longer ship debuggers like
`arm-linux-androideabi-gdb`, but instead one prebuilt binary `gdb`. We can
symlink this into place at least to get our detection still working, but it now
needs to be told what the sysroot is so it can correctly do... something. Long
story short, tests didn't pass with this change and after this change they pass.
mk: Fix bootstrapping cross-hosts on beta
The beta builds are currently failing, unfortunately, due to what is presumably
some odd behavior with our makefiles. The wrong bootstrap key is being used to
generate the stage1 cross-compiled libraries, which fails the build.
Interestingly enough if the targets are directly specified as part of the build
then it works just fine! Just a bare `make` fails...
Instead of trying to understand what's happening in the makefiles instead just
tweak how we configure the bootstrap key in a way that's more likely to work.
rustbuild: Add support for --enable-local-rust
This commit adds support for the `--enable-local-rust` `./configure` switch
which uses the locally installed `rustc` to bootstrap the compiler.
Implement Error trait for fmt::Error type
Fixes#33827.
r? @alexcrichton
Just one last thing: I added a feature name, but don't hesitate to ask me to change it if you think it doesn't fit well.
Apply visit_path to import prefixes by default
Overriding `visit_path` is not enough to visit all paths, some import prefixes are not visited and `visit_path_list_item` need to be overridden as well. This PR removes this catch, it should be less error prone this way. Also, the prefix is visited once now, not repeatedly for each path list item.
r? @eddyb
refactor autoderef to avoid prematurely registering obligations
Refactor `FnCtxt::autoderef` to use an external iterator and to not
register any obligation from the main autoderef loop, but rather to
register them after (and if) the loop successfully completes.
Fixes#24819Fixes#25801Fixes#27631Fixes#31258Fixes#31964Fixes#32320Fixes#33515Fixes#33755
r? @eddyb
