This rather crucial requirement was not checked. In most cases, that
didn't cause any trouble because the argument types are required to
outlive the call and are subtypes of a subformula of the callee type.
However, binary ops are taken by ref only indirectly, without it being
marked in the argument types, which led to the argument types not being
constrained anywhere causing spurious errors (as these are basically
unconstrainable, I don't think this change can break code). Of course,
the old way was also incorrent with contravariance, but that is still
unsound for other reasons.
This also improves rustc::front to get RUST_LOG to *somewhat* work.
Fixes#28999. That issue is one of the several regression introduced by #28669.
r? @pnkfelix
This rather crucial requirement was not checked. In most cases, that
didn't cause any trouble because the argument types are required to
outlive the call and are subtypes of a subformula of the callee type.
However, binary ops are taken by ref only indirectly, without it being
marked in the argument types, which led to the argument types not being
constrained anywhere causing spurious errors (as these are basically
unconstrainable, I don't think this change can break code). Of course,
the old way was also incorrent with contravariance, but that is still
unsound for other reasons.
This also improves rustc::front to get RUST_LOG to *somewhat* work.
Fixes#28999
I found these automatically, but fixed them manually to ensure the semantics are correct. I know things like these are hardly important, since they only marginally improve clarity. But at least for me typos and simple grammatical errors trigger an---unjustified---sense of unprofessionalism, despite the fact that I make them all the time and I understand that they're the sort of thing that is bound to slip through review.
Anyway, to find most of these I used:
* `ag '.*//.*(\b[A-Za-z]{2,}\b) \1\b'` for repeated words
* `ag '\b(the|this|those|these|a|it) (a|the|this|those|these|it)\b'` to find constructs like 'the this' etc. many false positives, but not too hard to scroll through them to actually find the mistakes.
* `cat ../../typos.txt | paste -d'|' - - - - - - - - - - - - - - - - - - - - - - | tr '\n' '\0' | xargs -0 -P4 -n1 ag`. Hacky way to find misspellings, but it works ok. I got `typos.txt` from [Wikipedia](https://en.wikipedia.org/wiki/Wikipedia:Lists_of_common_misspellings/For_machines)
* `ag '.*//.* a ([ae][a-z]|(o[^n])|(i[a-rt-z]))'` to find places where 'a' was followed by a vowel (requiring 'an' instead).
I also used a handful more one off regexes that are too boring to reproduce here.
Implement cannot-assume-parametricity (CAP) from RFC 1238, and add the
UGEH attribute.
----
Note that we check for the attribute attached to the dtor method, not
the Drop impl.
(This is just to match the specification of RFC and the tests; I am
not wedded to this approach.)
By RFC1214:
> Before calling a fn, we check that its argument and return types are WF.
The previous code only checked the trait-ref, which was not enough
in several cases.
As this is a soundness fix, it is a [breaking-change]. Some new annotations are needed, which I think are because of #18653 and the imperfection of `projection_must_outlive` (that can probably be worked around by moving the wf obligation later).
Fixes#28609
r? @nikomatsakis
libcore.rlib reduced from 19121 kiB to 15934 kiB - 20% win.
The librustc encoded AST is 9013500 bytes long - for the record, librustc consists of about 2254126 characters. Might be worth looking at.
r? @eddyb
By RFC1214:
Before calling a fn, we check that its argument and return types are WF. This check takes place after all higher-ranked lifetimes have been instantiated. Checking the argument types ensures that the implied bounds due to argument types are correct. Checking the return type ensures that the resulting type of the call is WF.
The previous code only checked the trait-ref, which was not enough
in several cases.
As this is a soundness fix, it is a [breaking-change].
Fixes#28609
As described in https://github.com/rust-lang/rfcs/pull/1298, the idea here is to make DefIds independent of changes to the content of other items. They are also *mostly* independent from ordering, so e.g. reordering two functions will change the defids, but it will not change the paths that they expand into (but this is not the case for some things, such as impls).
This is a major refactoring, so I did it in slices. The final commit is in some sense The Big One where most of the work is done. The earlier commits just pave the way by gradually refactoring accesses to the `node` field.
This is a [breaking-change] for plugin authors. The things you need to do to migrate your code are as follows:
1. For local def-ids, rather than do `def_id.node`, call `tcx.map.as_local_node_id(def_id)`.
2. To construct a local def-id, call `tcx.map.local_def_id(node_id)`.
3. Note that you cannot make def-ids for any node, but only for "definitions" -- which include all items, as well as a number of other things, but not e.g. arbitrary expressions.
4. You can get the path to a def-id by calling `tcx.def_path(def_id)`.
One thing that is NOT part of this PR, but which I plan do in a follow-up, is converting uses of the existing `with_path` API to use `def_path`, which is basically the same.
r? @eddyb (or @nrc)
