| Age | Commit message (Collapse) | Author | Lines |
|---|
|
Ty{Adt|Array|Slice|RawPtr|Ref|FnDef|FnPtr|Dynamic|Closure|Generator|GeneratorWitness|Never|Tuple|Projection|Anon|Infer|Error}
|
|
|
|
Fix typos found by codespell.
|
|
Rename CodeMap/FileMap to SourceMap/SourceFile
A first renaming for #51574
|
|
52985: cause cycle err on inf trait normalization
Issue: #52985
- If an existential type is defined, but no user code infers the
concrete type behind the existential type, normalization would
infinitely recurse on this existential type which is only defined in
terms of itself.
- Instead of raising an inf recurse error, we cause a cycle error to
help highlight that the issue is that the type is only defined in terms
of itself.
- Three known potential improvements:
- If type folding itself was exposed as a query, used by
normalization and other mechanisms, cases that would cause infinite recursion would
automatically cause a cycle error.
- The span for the cycle error should be improved to point to user
code that fails to allow inference of the concrete type of the existential type,
assuming that this error occurs because no user code can allow inference the
concrete type.
- A mechanism to extend the cycle error with a helpful note would be nice. Currently,
the error is built and maintained by src/librustc/ty/query/plumbing,
with no known way to extend the information that the error gets built
with.
r? @oli-obk
|
|
|
|
|
|
skip trivial `Sized` predicates
This came to about a 2% win for me in cargo. Small, but hey.
r? @eddyb
|
|
- If an existential type is defined, but no user code infers the
concrete type behind the existential type, normalization would
infinitely recurse on this existential type which is only defined in
terms of itself.
- Instead of raising an inf recurse error, we cause a cycle error to
help highlight that the issue is that the type is only defined in terms
of itself.
- Three known potential improvements:
- If type folding itself was exposed as a query, used by
normalization and other mechanisms, cases that would cause infinite recursion would
automatically cause a cycle error.
- The span for the cycle error should be improved to point to user
code that fails to allow inference of the concrete type of the existential type,
assuming that this error occurs because no user code can allow inference the
concrete type.
- A mechanism to extend the cycle error with a helpful note would be nice. Currently,
the error is built and maintained by src/librustc/ty/query/plumbing,
with no known way to extend the information that the error gets built
with.
|
|
Fixes #52786
|
|
|
|
|
|
Fixes #51649
|
|
|
|
|
|
|
|
|
|
Extra allocations are a significant cost of NLL, and the most common
ones come from within `Canonicalizer`. In particular, `canonical_var()`
contains this code:
indices
.entry(kind)
.or_insert_with(|| {
let cvar1 = variables.push(info);
let cvar2 = var_values.push(kind);
assert_eq!(cvar1, cvar2);
cvar1
})
.clone()
`variables` and `var_values` are `Vec`s. `indices` is a `HashMap` used
to track what elements have been inserted into `var_values`. If `kind`
hasn't been seen before, `indices`, `variables` and `var_values` all get
a new element. (The number of elements in each container is always the
same.) This results in lots of allocations.
In practice, most of the time these containers only end up holding a few
elements. This PR changes them to avoid heap allocations in the common
case, by changing the `Vec`s to `SmallVec`s and only using `indices`
once enough elements are present. (When the number of elements is small,
a direct linear search of `var_values` is as good or better than a
hashmap lookup.)
The changes to `variables` are straightforward and contained within
`Canonicalizer`. The changes to `indices` are more complex but also
contained within `Canonicalizer`. The changes to `var_values` are more
intrusive because they require defining a new type
`SmallCanonicalVarValues` -- which is to `CanonicalVarValues` as
`SmallVec` is to `Vec -- and passing stack-allocated values of that type
in from outside.
All this speeds up a number of NLL "check" builds, the best by 2%.
|
|
|
|
|
|
|
|
convert NLL ops to caches
This is a extension of <https://github.com/rust-lang/rust/pull/51460>. It uses a lot more caching than we used to do. This caching is not yet as efficient as it could be, but I'm curious to see the current perf results.
This is the high-level idea: in the MIR type checker, use [canonicalized queries](https://rust-lang-nursery.github.io/rustc-guide/traits/canonical-queries.html) for all the major operations. This is helpful because the MIR type check is operating in a context where all types are fully known (mostly, anyway) but regions are completely renumbered. This means we often wind up with duplicate queries like `Foo<'1, '2> :Bar` and `Foo<'3, '4>: Bar`. Canonicalized queries let us re-use the results. By the final commit in this PR, we can essentially just "read off" the resulting region relations and add them to the NLL type check.
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
As the comment explains, this is needed to prevent subtype from going
awry in higher-ranked cases, due to #33684. The proper fix here is
introducing universes (#48536).
|
|
|
|
|
|
|
|
This lets us simplify a few type aliases.
|
|
|
|
|
|
|
|
|
|
|
|
Notably, excluding ReSkolemized
|
