nll part 5
Next round of changes from the nll-master branch.
Extensions:
- we now propagate ty-region-outlives constraints out of closures and into their creator when necessary
- we fix a few ICEs that can occur by doing liveness analysis (and the resulting normalization) during type-checking
- we handle the implicit region bound that assumes that each type `T` outlives the fn body
- we handle normalization of inputs/outputs in fn signatures
Not included in this PR (will come next):
- handling `impl Trait`
- tracking causal information
- extended errors
r? @arielb1
arbitrary_self_types: add support for raw pointer `self` types
This adds support for raw pointer `self` types, under the `arbitrary_self_types` feature flag. Types like `self: *const Self`, `self: *const Rc<Self>`, `self: Rc<*const Self` are all supported. Object safety checks are updated to allow`self: *const Self` and `self: *mut Self`.
This PR does not add support for `*const self` and `*mut self` syntax. That can be added in a later PR once this code is reviewed and merged.
#44874
r? @arielb1
fix broken assertion in type_param
Nested generics (aka method generics) in trait methods don't have an
*additional* Self parameter in their own type parameter list (they have
a Self parameter in the parent generics), so don't try to check we're
correctly adjusting for it.
Fixes#46568.
r? @eddyb
This simple patch resolves#46756 (which was specifically about the case of
casts, but it would be poor form indeed to fix a reported issue without at
least a cursory attempt at answering the immortal question, "How does this bug
generalize?").
Point at var in short lived borrows instead of drop location
For RLS' sake, point at the borrow location as primary span for short lived borrows, instead of the borrow drop location.
Fix#39268.
The input/output types found in `UniversalRegions` are not normalized.
The old code used to assign them directly into the MIR, which would
lead to errors when there was a projection in a argument or return
type. This also led to some special cases in the `renumber` code.
We now renumber uniformly but then pass the input/output types into
the MIR type-checker, which equates them with the types found in MIR.
This allows us to normalize at the same time.
This allows us to re-use the `normalize` method on `TypeCheck`, which
is important since normalization may create fresh region
variables. This is not an ideal solution, though, since the current
representation of "liveness constraints" (a vector of (region, point)
pairs) is rather inefficient. Could do somewhat better by converting
to indices, but it'd still be less good than the older code. Unclear
how important this is.
Before, we would always have a `Some` ClosureRegionRequirements if we
were inferring values for a closure. Now we only do is it has a
non-empty set of outlives requirements.
Lifetime Resolution for Generic Associated Types
Tracking Issue: https://github.com/rust-lang/rust/issues/44265
r? @nikomatsakis
This PR implements lifetime resolution for generic associated types. 🎉
## Remaining Work Before Merge
I'm going to go do these things in the next day or so. Please let me know if you spot anything in my changes until then.
- [x] If I'm not mistaken, at least some tests should pass now. I need to go through the tests and re-enable the ones that should work by removing the appropriate `~ ERROR` comments
