This commit stops well-formedness checking applying to unreachable code
and therefore stops some of the ICEs that the intended solution taken by
this PR causes.
By disabling these checks, we can land the other fixes and larger
refactors that this PR includes.
This commit moves well-formedness check for the
`UserTypeAnnotation::Ty(..)` case from always running to only when the
code is reachable. This solves the ICE that resulted from
`src/test/ui/issue-54943-1.rs` (a minimal repro of `dropck-eyepatch`
run-pass tests that failed).
The main well-formedness check that was intended to be run despite
unreachable code still is, that being the
`UserTypeAnnotation::TypeOf(..)` case. Before this PR, the other case
wasn't being checked at all.
It is possible to fix this ICE while still always checking
well-formedness for the `UserTypeAnnotation::Ty(..)` case but that
solution will ICE in unreachable code for that case, the diff for
that change [can be found here](0).
[0]: https://gist.github.com/davidtwco/f9751ffd9c0508f7251c0f17adc3af53
This commit adds support for user type annotations in variables declared
using `ref` bindings. When a variable declared using a `ref` binding,
then the `LocalDecl` has the type `&T` where the `&` was introduced by
the `ref` binding but the canonicalized type annotation has only a
`T` since the reference is implicit with the `ref` binding.
Therefore, to support type annotations, the canonicalized type
annotation either needs wrapped in a reference, or the `LocalDecl` type
must have a wrapped reference removed for comparison. It is easier to
remove the outer reference from the `LocalDecl` for the purpose of
comparison, so that is the approach this commit takes.
This commit uses the map introduced by the previous commit to ensure
that types are always checked for well-formedness by the NLL type check.
Previously, without the map introduced by the previous commit, types
would not be checked for well-formedness if the `AscribeUserType`
statement that would trigger that check was removed as unreachable code.
This commit refactors the `UserTypeAnnotation` type to be referred to by
an index within `UserTypeProjection`. `UserTypeAnnotation` is instead
kept in an `IndexVec` within the `Mir` struct.
Further, instead of `UserTypeAnnotation` containing canonicalized types,
it now contains normal types and the entire `UserTypeAnnotation` is
canonicalized. To support this, the type was moved from the `rustc::mir`
module to `rustc::ty` module.
This avoids all sorts of confusing issues with using both `dest_place`
and `self` in the `propagate_call_return` function in the
`BitDenotation` implementation for `Borrows`.
Enum layout optimizations mean that the discriminant of an enum may not
be stored in a tag disjoint from the rest of the fields of the enum.
Stop borrow checking as though they are.
This commit puts a fix in place for the ICE in region naming code so
that it doesn't break the compiler. However, this results in the
diagnostic being poorer as the borrow explanation that was causing the
ICE is not being added - this should be fixed as a follow-up.
Replace usages of `..i + 1` ranges with `..=i`.
Before this change we were using old computer code techniques. After this change we use the new and improved computer code techniques.
Implement chalk unification routines
`ResolventOps` and `AggregateOps` are mostly straightforwardly translated from chalk. I had caught a few bugs already in my `chalk` branch and backported fixes to this branch, but there may be other ones left. EDIT: I hope there are none left now :)
Fixes#54935.
ICE with #![feature(nll)] and elided lifetimes
Fixes#55394.
This commit fixes an ICE and determines the correct return span in cases
with a method implemented on a struct with an an elided lifetime.
r? @pnkfelix
Do not attempt to ascribe projections out of a ty var
If we encounter `_` ascribed to structural pattern like `(a, b)`, just skip relate_types.
Fix#55552
