NLL: Add closure cannot be moved note.
Fixes#57098.
This PR extends existing logic for checking whether a closure that
is `FnOnce` and therefore moves variables that it captures from the
environment has already been invoked when being invoked again.
Now, this logic will also check whether the closure is being moved after
previously being moved or invoked and add an appropriate note.
r? @pnkfelix
Add support for trait-objects without a principal
The hard-error version of #56481 - should be merged after we do something about the `traitobject` crate.
Fixes#33140.
Fixes#57057.
r? @nikomatsakis
Implement the Re-rebalance coherence RFC
This is the first time I touch anything in the compiler so just tell me if I got something wrong.
Big thanks to @sgrif for the pointers where to look for those things.
cc #55437
make `panictry!` private to libsyntax
This commit completely removes usage of the `panictry!` macro from
outside libsyntax. The macro causes parse errors to be fatal, so using
it in libsyntax_ext caused parse failures *within* a syntax extension to
be fatal, which is probably not intended.
Furthermore, this commit adds spans to diagnostics emitted by empty
extensions if they were missing, à la #56491.
Forbid recursive impl trait
There is no type T, such that `T = [T; 2]`, but impl Trait could sometimes
be to circumvented this.
This patch makes it a hard error for an opaque type to resolve to such a
"type". Before this can be merged it needs
- [x] A better error message - it's good enough for now.
- [x] A crater run (?) to see if this any real-world code
closes#47659
Allow to dispatch fn traits depending on number of parameters
Hello,
By following @eddyb's advise on issue #45510, I managed to have the snippets of code in #45510 and #18952 passing without breaking older diagnostics.
EDIT: the codegen tests breakage I experienced is due to the poor quality of my laptop.
If any kind reviewer has any advice, you are very welcome.
Universes
This PR transitions the compiler to use **universes** instead of the **leak-check**. It is marked as [WIP] for a few reasons:
- The diagnostics at present are terrible =)
- This changes the behavior of coherence, regressing some things that used to compile
The goals of this PR at present are:
- To start getting some eyes on the code
- To do a crater run
- To see the full travis results (due to https://github.com/rust-lang/rust/issues/52452, I am not able to run the full test suite locally anymore at present)
The first few commits in the PR are changing how `evaluate` treats regions. We now track whether region comparisons occurred, reverting the "staticized" query approach that @arielb1 put in. The problem with "staticized" queries is that it relied on the leak-check to get higher-ranked things correct, and we are removing the leak-check in this PR series, so that caused problems.
You can see at the end a collection of test updates. Mostly we behave the same but with atrocious diagnostics, but there are a number of cases where we used to error and now no longer do, as well as single case where we used to **not** error but we now do (the coherence-subtyping change).
(Note: it would be possible to do a version of leak-check that propagates universe information and recover the old behavior. I am reluctant to do so because I'd like to leave us room to get more precise -- e.g., I want to eventually handle things like `exists<'a> { for<'b> { if ('a: 'b) { 'a: 'b } } }` which presently the leak-check cannot cope with etc. Also because it seems more consistent to me: most folks I've talked to expect the new behavior and are surprised to learn that binding sites were so significant before when it comes to coherence. One question is, though, to what extent are people relying on this in the wild?)
