(While still prohibiting explicit and in-band in the same header.)

Bring in a few updates and fixes, mostly a standard update.

Otherwise, custom drivers will have to use their own copy of `getopts`, which
won't match the types used in `CompilerCalls`.

In the 2018 edition, when suggesting traits to import that implement a
given method that is being invoked, suggestions will now include the
`crate::` prefix if the suggested trait is local to the current crate.

Avoid hardcoding and special-casing the `std` crate name in the item
path logic by moving the prelude crate name logic into the `Session`
type so it can be reused in the item path logic and resolve module.

This commit takes a different approach to add the `crate::` prefix to
item paths than previous commits. Previously, recursion was stopped
after a prelude crate name was pushed to the path. It is theorized that
this was the cause of the linking issues since the same path logic is
used for symbol names and that not recursing meant that details were
being missed that affect symbol names. As of this commit, instead of
ceasing recursion, a flag is passed through to any subsequent recursive
calls so that the same effect can be achieved by checking that flag.

we are consolidating `cannot bind by-move and by-ref in the same
pattern` message present on the different lines into single diagnostic
message.

To do this, we are first gathering those spans into the vector
after that we are throwing them with the help of MultiSpan in
a separate block.

Addresses: rust-lang#53840

closes rust-lang#54678

closes rust-lang#54678

rust-lang#53840: Consolidate pattern check errors

rust-lang#53840  on this PR we are aggregating `cannot bind by-move and by-ref in the same pattern` message present on the different lines into one diagnostic message. Here we are first gathering those `spans` on `vector` then we are throwing them with the help of `MultiSpan`
r? @estebank

Addresses: rust-lang#53480

Allow both explicit and elided lifetimes in the same impl header

While still prohibiting explicit and in-band in the same header.

Fixes rust-lang#54456

As usual, I don't know the broader context of the code I'm changing, so please let me know whatever I can do better.

Pre-existing test that mixing explicit and in-band remains an error: https://github.com/rust-lang/rust/blob/master/src/test/ui/in-band-lifetimes/E0688.rs

Add `crate::` to trait suggestions in Rust 2018.

Fixes rust-lang#54559.

In the 2018 edition, when suggesting traits to import that implement a
given method that is being invoked, suggestions will now include the
`crate::` prefix if the suggested trait is local to the current crate.

r? @nikomatsakis

…tsakis

Update Cargo's submodule

Bring in a few updates and fixes, mostly a standard update.

make run-pass tests with empty main just compile-pass tests

Many run-pass tests have an empty main, so there is not actually any point in running them. This makes them `compile-pass` tests instead, saving some time (generating the binary and then running it).

For now I did this only for `run-pass/issues`; if there is interest I can also do it for the other directories. I used `^\s*fn\s+main\(\s*\)\s*\{\s*\}` as regexp to identify these files.

Use impl_header_lifetime_elision in libcore

The feature is approved for stabilization, so let's use it to remove about 300 `'a`s.

Tracking issue for the feature: rust-lang#15872

…=pnkfelix

Re-export `getopts` so custom drivers can reference it.

Otherwise, custom drivers will have to use their own copy of `getopts`, which won't match the types used in `CompilerCalls`.

do not promote comparing function pointers

This *could* break existing code that relied on fn ptr comparison getting promoted to `'static` lifetime.

Fixes rust-lang#54696

…omatsakis

Renumber `proc_macro` tracking issues

Lots of issue links in the compiler still point to rust-lang#38356 which is a bit of a monster issue that isn't serving much purpose any more. I've split the issue into a number of more fine-grained tracking issues to track stabilizations.

make `CStr::from_bytes_with_nul_unchecked()` a const fn

closes rust-lang#54678