MIR: terminate unreachable blocks in construct_const
Fixes#46843.
#45821 added unreachable blocks in matches, which were terminated in
construct_fn but not in construct_const, causing a panic due to "no
terminator on block" when constants involved matching on enums.
The "unimplemented expression type" error may go away in the future, the
key is that we see the E0015 about using a non-const function and then
don't ICE.
Implement non-mod.rs mod statements
Fixes https://github.com/rust-lang/rust/issues/45385, cc https://github.com/rust-lang/rust/issues/44660
This will fail tidy right now because it doesn't recognize my UI tests as feature-gate tests. However, I'm not sure if compile-fail will work out either because compile-fail usually requires there to be error patterns in the top-level file, which isn't possible with this feature. What's the recommended way to handle this?
Fixes#46843.
#45821 added unreachable blocks in matches, which were terminated in
construct_fn but not in construct_const, causing a panic due to "no
terminator on block" when constants involved matching on enums.
The "unimplemented expression type" error may go away in the future, the
key is that we see the E0015 about using a non-const function and then
don't ICE.
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
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.
[MIR-borrowck] Two phase borrows
This adds limited support for two-phase borrows as described in
http://smallcultfollowing.com/babysteps/blog/2017/03/01/nested-method-calls-via-two-phase-borrowing/
The support is off by default; you opt into it via the flag `-Z two-phase-borrows`
I have written "*limited* support" above because there are simple variants of the simple `v.push(v.len())` example that one would think should work but currently do not, such as the one documented in the test compile-fail/borrowck/two-phase-reservation-sharing-interference-2.rs
(To be clear, that test is not describing something that is unsound. It is just providing an explicit example of a limitation in the implementation given in this PR. I have ideas on how to fix, but I want to land the work that is in this PR first, so that I can stop repeatedly rebasing this branch.)
trait alias infrastructure
This will be an implementation of trait aliases (RFC 1733, #41517).
Progress so far:
- [x] Feature gate
- [x] Add to parser
- [x] `where` clauses
- [x] prohibit LHS type parameter bounds via AST validation https://github.com/rust-lang/rust/pull/45047#discussion_r143575575
- [x] Add to AST and HIR
- [x] make a separate PathSource for trait alias contexts https://github.com/rust-lang/rust/pull/45047#discussion_r143353932
- [x] Stub out enough of typeck and resolve to just barely not ICE
Postponed:
- [ ] Actually implement the alias part
- [ ] #21903
- [ ] #24010
I need some pointers on where to start with that last one. The test currently does this:
```
error[E0283]: type annotations required: cannot resolve `_: CD`
--> src/test/run-pass/trait-alias.rs:34:16
|
34 | let both = foo();
| ^^^
|
= note: required by `foo`
```
Validate miri against the HIR const evaluator
r? @eddyb
cc @alexcrichton @arielb1 @RalfJung
The interesting parts are the last few functions in `librustc_const_eval/eval.rs`
* We warn if miri produces an error while HIR const eval does not.
* We warn if miri produces a value that does not match the value produced by HIR const eval
* if miri succeeds and HIR const eval fails, nothing is emitted, but we still return the HIR error
* if both error, nothing is emitted and the HIR const eval error is returned
So there are no actual changes, except that miri is forced to produce the same values as the old const eval.
* This does **not** touch the const evaluator in trans at all. That will come in a future PR.
* This does **not** cause any code to compile that didn't compile before. That will also come in the future
It would be great if someone could start a crater run if travis passes
Since we are now checking activation points, I removed one of the
checks at the reservation point. (You can see the effect this had on
two-phase-reservation-sharing-interference-2.rs)
Also, since we now have checks at both the reservation point and the
activation point, we sometimes would observe duplicate errors (since
either one independently interferes with another mutable borrow). To
deal with this, I used a similar strategy to one used as discussed on
issue #45360: keep a set of errors reported (in this case for
reservations), and then avoid doing the checks for the corresponding
activations. (This does mean that some errors could get masked, namely
for conflicting borrows that start after the reservation but still
conflict with the activation, which is unchecked when there was an
error for the reservation. But this seems like a reasonable price to
pay.)
move `resolve_lifetimes` into a proper query
Now that we made `resolve_lifetimes` into a query, elision errors no
longer abort compilation, which affects some tests.
Also, remove `dep_graph_crosscontaminate_tables` -- there is no a path in
the dep-graph, though red-green handles it. The same scenario
is (correctly) tested by issue-42602.rs in any case.
r? @michaelwoerister
Now that we made `resolve_lifetimes` into a query, elision errors no
longer abort compilation, which affects some tests.
Also, remove `dep_graph_crosscontaminate_tables` -- there is no a path in
the dep-graph, though red-green handles it. The same scenario
is (correctly) tested by issue-42602.rs in any case.
