NLL Diagnostic Review 3: Unions not reinitialized after assignment into field
Fixes#55651, #55652.
This PR makes two changes:
First, it updates the dataflow builder to add an init for the place
containing a union if there is an assignment into the field of
that union.
Second, it stops a "use of uninitialized" error occuring when there is an
assignment into the field of an uninitialized union that was previously
initialized. Making this assignment would re-initialize the union, as
tested in `src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr`.
The check for previous initialization ensures that we do not start
supporting partial initialization yet (cc #21232, #54499, #54986).
This PR also fixes#55652 which was marked as requiring investigation
as the changes in this PR add an error that was previously missing
(and mentioned in the review comments) and confirms that the error
that was present is correct and a result of earlier partial
initialization changes in NLL.
r? @pnkfelix (due to earlier work with partial initialization)
cc @nikomatsakis
NLL: Update box insensitivity test
This is just keeping one of our tests honest with respect to NLL, in two ways:
1. Adds uses of borrows that would otherwise be too short to observe the error that we would have expected to see...
2. ... I say "would have expected" because all of the errors in this file are part of the reversion of rust-lang/rfcs#130 that is attached to NLL (you can see more discussion of this here https://github.com/rust-lang/rust/issues/43234#issuecomment-411017768 )
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
(The commit prior to this actual passes our test suite, "thanks"
to #55695. But since I am aware of that bug, I took advantage of it
in choosing how to order my commit series...)
This is a variant of `ui/borrowck/borrowck-closures-mut-of-imm.rs`
that I used to help identify what changes I needed to make to the
latter file in order to recover its instances of E0524 under NLL.
(Basically this test includes the changes you'd need to make to
`ui/borrowck/borrowck-closures-mut-of-imm.rs` in order to get rid of
occurrences of E0596. And then I realized that one needs to add
invocations of the closures in order to properly extend the mutable
reborrows in a manner such that NLL will roughly match AST-borrowck.)
Most of the time we want to robustify tests, but in this case this
test is deliberately encoding artifacts of AST-borrowck. So instead
of adding artificial uses that would obscure the aspects of
AST-borrowck that are being tests, we instead use revisions and then
mark the cases that apply to NLL as well as AST-borrowck.
This commit makes two changes:
First, it updates the dataflow builder to add an init for the place
containing a union if there is an assignment into the field of
that union.
Second, it stops a "use of uninitialized" error occuring when there is an
assignment into the field of an uninitialized union that was previously
initialized. Making this assignment would re-initialize the union, as
tested in `src/test/ui/borrowck/borrowck-union-move-assign.nll.stderr`.
The check for previous initialization ensures that we do not start
supporting partial initialization yet (cc #21232, #54499, #54986).
borrowck=migrate must look at parents of closures
This fixes the NLL migration mode (which is the default with edition=2018) to inspect all parents of a closure in addition to the closure itself when looking to see if AST-borrowck issues an error for the given code.
This should be a candidate for beta backport.
Fix#55492
Do not allow moving out of thread local under ast borrowck
AST borrowck failed to prevent moving out of a thread-local static.
This was broken. And it also (sometimes?) caused an ICE during drop elaboration.
Fix#47215Fix#54797
This gives at least some explanation for why a borrow is expected to
last for a certain free region. Also:
* Reports E0373: "closure may outlive the current function" with NLL.
* Special cases the case of returning a reference to (or value
referencing) a local variable or temporary (E0515).
* Special case assigning a reference to a local variable in a closure
to a captured variable.
regression test for move out of borrow via pattern
regression test for issue #54597.
(We may have other tests that cover this, but I couldn't immediately find them associated with the PR that originally fixed the ICE here.)
NLL: change compare-mode=nll to use borrowck=migrate
Fixes#55118.
This PR is split into two parts:
The first commit is a minor change that fixes a flaw in the existing `borrowck=migrate` implementation whereby a lint that was promoted to an error in the AST borrow checker would result in the same lint from the NLL borrow checker being downgraded to a warning in migrate mode. This PR fixes this by ensuring lints are exempt from buffering in the NLL borrow checker.
The second commit updates `compiletest` to make the NLL compare mode use `-Z borrowck=migrate` rather than `-Z borrowck=mir`. The third commit shows all the test output changes that result from this.
r? @pnkfelix
This commit updates the test output for the updated NLL compare mode
that uses `-Z borrowck=migrate` rather than `-Z borrowck=mir`. The
previous commit changes `compiletest` and this commit only updates
`.nll.stderr` files.
NLL says "borrowed content" instead of more precise "dereference of raw pointer"
Part of #52663.
Previously, move errors involving the dereference of a raw pointer would
say "borrowed content". This commit changes it to say "dereference of
raw pointer".
r? @nikomatsakis
cc @pnkfelix
Now when a `FnMut` closure is returning a closure that contains a
reference to a captured variable, we provide an error that makes it more
clear what is happening.
Previously, move errors involving the dereference of a raw pointer would
say "borrowed content". This commit changes it to say "dereference of
raw pointer".
Give a special message when the later use is from a call. Use the span
of the callee instead of the whole expression. For conflicting borrow
messages say that the later use is of the first borrow.
This commit special cases the move out of borrowed content error,
previously:
```
error[E0507]: cannot move out of borrowed content
--> src/main.rs:7:10
|
7 | drop(x.field);
| ^ cannot move out of borrowed content
```
to instead mention that it is a move out of a `Rc`/`Arc` which is more
helpful:
```
error[E0507]: cannot move out of an `Rc`
--> src/main.rs:7:10
|
7 | drop(x.field);
| ^ cannot move out of an `Rc`
```
Report when borrow could cause `&mut` aliasing during Drop
We were already issuing an error for the cases where this cropped up, so this is not fixing any soundness holes. The previous diagnostic just wasn't accurately describing the problem in the user's code.
Fix#52059
