Remove useless help part
Part of #32658.
I think this error should be splitted into two parts, each more specific (`anonymous function` vs `type method`).
As discussed in
https://github.com/rust-lang/cargo/issues/4040#issuecomment-321639074
This is a redirect meant to be replaced once cargo docs have been
converted to mdbook. We just want *a* URL to ride the trains for now so
that we can print doc.rust-lang.org/cargo in the paper book and
guarantee that it will go *somewhere* useful by the time the book is
printed.
Implemented as a meta redirect in HTML because we don't currently have
any google juice at doc.rust-lang.org/cargo to lose.
Stop testing `i586-pc-windows-msvc` on AppVeyor.
Fixes#43881. Reduces AppVeyor test time back to ~2 hours on average.
The i586 libstd was never tested before Aug 13th, so this PR brings the situation back to the previous status-quo.
MIR borrow check (under debug flag)
Here is the current state of MIR borrow check.
It consists of (1.) some refactoring, (2.) a dataflow analysis to identify the borrows themselves, and (3.) a mir "transform" that does the borrow check itself based on the aforementioned dataflow results.
(There's also a drive-by fix to dataflow that I can factor into a separate PR if necessary. Interestingly I could not find a way to observe the bug outside of MIR borrowck.)
To be clear, this branch is not ready to be used as the default borrow check. Thus the code is guarded: To get mir-borrowck to run, you need to either supply an attribute `#[rustc_mir_borrowck]` or a debug flag `-Z borrowck-mir`.
Here are the main issues with the current MIR borrowck as it stands in this PR:
* No Notes emitted yet, just errors. (So the feedback is definitely inferior compared to AST borrowck today)
* Lvalue rendering differs between Ast and Mir. (Mostly minor, but replacement of field names with indices is very bad; big priority for me to fix ASAP.)
* Lots of ICEs (presumably because some MIR operations used here have well-formedness assumptions that are violated in borrowck-broken code)
* Conflates lots of cases that are distinguished by AST-borrowck
* Conflates "uninitialized" with "moved" (special case of previous bullet, one that I think should be fixed ASAP)
(I am hoping to fix as many of the above issues as I can in the near term, but I also would like to land this even if they are *not* all fixed, because the rebasing effort is getting to be a real drag.)
Added two fixmes: The `SimplifyBranches` pass cannot stay where it is,
and `BorrowckMir` should be a query, not a pass. But I am going to
leave those changes to a future PR.
One can either use `-Z borrowck-mir` or add the `#[rustc_mir_borrowck]` attribute
to opt into MIR based borrow checking.
Note that regardless of whether one opts in or not, AST-based borrow
check will still run as well. The errors emitted from AST-based
borrow check will include a "(Ast)" suffix in their error message,
while the errors emitted from MIR-based borrow check will include a
"(Mir)" suffix.
post-rebase: removed check for intra-statement mutual conflict;
replaced with assertion checking that at most one borrow is generated
per statement.
post-rebase: removed dead code: `IdxSet::pairs` and supporting stuff.
