Fixes rust-lang#69446

When we encounter a region error involving an `FnMut` closure, we
display a specialized error message. However, we currently do not
tell the user which upvar was captured. This makes it difficult to
determine the cause of the error, especially when the closure is large.

This commit records marks constraints involving closure upvars
with `ConstraintCategory::ClosureUpvar`. When we decide to 'blame'
a `ConstraintCategory::Return`, we additionall store
the captured upvar if we found a `ConstraintCategory::ClosureUpvar` in
the path.

When generating an error message, we point to relevant spans if we have
closure upvar information available. We further customize the message if
an `async` closure is being returned, to make it clear that the captured
variable is being returned indirectly.

…tains

See:
https://reviews.llvm.org/D70779
https://reviews.llvm.org/D70779#C1703593NL568

LLVM 10 merged into master at:
rust-lang#67759

… return types

Add needs-sanitizer-{address,leak,memory,thread} directive indicating
that test requires target with support for specific sanitizer.

This is an addition to the existing needs-sanitizer-support directive
indicating that test requires a sanitizer runtime library.

…n, r=nikomatsakis

Display information about captured variable in `FnMut` error

Fixes rust-lang#69446

When we encounter a region error involving an `FnMut` closure, we
display a specialized error message. However, we currently do not
tell the user which upvar was captured. This makes it difficult to
determine the cause of the error, especially when the closure is large.

This commit records marks constraints involving closure upvars
with `ConstraintCategory::ClosureUpvar`. When we decide to 'blame'
a `ConstraintCategory::Return`, we additionall store
the captured upvar if we found a `ConstraintCategory::ClosureUpvar` in
the path.

When generating an error message, we point to relevant spans if we have
closure upvar information available. We further customize the message if
an `async` closure is being returned, to make it clear that the captured
variable is being returned indirectly.

…, r=nikomatsakis

Further tweak lifetime errors involving `dyn Trait` and `impl Trait` in return position

* Suggest substituting `'static` lifetime in impl/dyn `Trait + 'static` instead of `Trait + 'static + '_`
* When `'static` is explicit, also suggest constraining argument with it
* Reduce verbosity of suggestion message and mention lifetime in label
* Tweak output for overlapping required/captured spans
* Give these errors an error code

Follow up to rust-lang#72543.

r? @nikomatsakis

…iour, r=hanna-kruppe

Clarify the behaviour of Pattern when used with methods like str::contains

Fixes rust-lang#45507.

I used the previous work by @Emerentius (thanks !), added a paragraph and checked the links (they work for me but I'm not against someone else checking them too).

…akis

compiletest: Add directives to detect sanitizer support

Add needs-sanitizer-{address,leak,memory,thread} directive indicating
that test requires target with support for specific sanitizer.

This is an addition to the existing needs-sanitizer-support directive
indicating that test requires a sanitizer runtime library.

The existing needs-sanitizer-support directive could be incorporated into the
new ones, but I decided to retain it, since it enables running sanitizer
codegen tests even when building of sanitizer runtime libraries is disabled.

Fix link error with #[thread_local] introduced by rust-lang#71192

r? @oli-obk

Rename "cyclone" to "apple-a7" per changes in upstream LLVM

It looks like they intended to keep "cyclone" as a legacy option, but removed it from the list of subtarget features. This created a flood of warnings when targeting aarch64-apple-ios, and probably also created incorrectly optimized artifacts.

See:
https://reviews.llvm.org/D70779
https://reviews.llvm.org/D70779#C1703593NL568

LLVM 10 merged into master at:
rust-lang#67759

…Simulacrum

Use the built cargo for cargotest.

cargotest was using the beta (bootstrap) cargo. This changes it so that it will use the locally built cargo. This is intended to provide a sort of smoke test to ensure Cargo is functional. This *shouldn't* have any real impact on the CI build time.  The cargotest job also happens to run cargo's testsuite, so it should already be building cargo.

Note: This will fail until rust-lang#73266 is merged.

Fix links when pinging notification groups

I think a blank line is necessary for the link to be applied.
Not sure who to assign, r? @Dylan-DPC