Fixes rust-lang#41964.

This is a breaking change.

.

Generally useful, but also a prerequisite for moving a bunch of unit tests off Range::step_by.

iterator_step_by has decoupled their futures, so the tracking issue should split.

regression test for rust-lang#37550

Remove `FusedIterator` implementation of `iter::Scan`

Fixes rust-lang#41964.

This is a breaking change.

trace_macro: Show both the macro call and its expansion. rust-lang#42072.

See rust-lang#42072 for the initial motivation behind this.

The change is not the minimal fix, but I want this behavior almost every time I use `trace_macros`.

…excrichton

Override size_hint and propagate ExactSizeIterator for iter::StepBy

Generally useful, but also a prerequisite for moving a bunch of unit tests off `Range*::step_by`.

A small non-breaking subset of rust-lang#42110 (which I closed).

Includes two small documentation changes @ivandardi requested on that PR.

r? @alexcrichton

…excrichton

Give step_trait a distinct tracking issue from step_by

iterator_step_by has decoupled their futures, so the tracking issue should split.

Old issue: rust-lang#27741
New issue: rust-lang#42168

r? @alexcrichton (another follow-up to closed PR rust-lang#42110 (comment))

…x-1, r=nikomatsakis

incr.comp.: Track expanded spans instead of FileMaps.

This PR removes explicit tracking of FileMaps in response to rust-lang#42101. The reasoning behind being able to just *not* track access to FileMaps is similar to why we don't track access to the `DefId->DefPath` map:
1. One can only get ahold of a `Span` value by accessing the HIR (for local things) or a `metadata::schema::Entry` (for things from external crates).
2. For both of these things we compute a hash that incorporates the *expanded spans*, that is, what we hash is in the (FileMap independent) format `filename:line:col`.
3. Consequently, everything that emits a span should already be tracked via its dependency to something that has the span included in its hash and changes would be detected via that hash.

One caveat here is that we have to be conservative when exporting things in metadata. A crate can be built without debuginfo and would thus by default not incorporate most spans into the metadata hashes. However, a downstream crate can make an inline copy of things in the upstream crate and span changes in the upstream crate would then go undetected, even if the downstream uses them (e.g. by emitting debuginfo for an inlined function). For this reason, we always incorporate spans into metadata hashes for now (there might be more efficient ways to handle this safely when red-green tracking is implemented).

r? @nikomatsakis

…eddyb

Remove all instances of fragment_infos and fragment sets

Remove unused fragment structs. This was suggested by @eddyb in IRC: [botbot link](https://botbot.me/mozilla/rustc/2017-05-23/?msg=86016574&page=2).

rust-src: include everything needed to compile libstd with jemalloc

I am not very happy about all this `Path::new`, but did not find a nice way to avoid it. Also, this shouldn't be very performance-critical.

With this patch, rust-src-1.19.0-dev.tar.gz grows from 1.4 to 3.1 MiB (new uncompressed size: 15.5 MiB). Not great, but shipping incomplete sources is also not great, and this is still much smaller than pre-rust-lang#41546. Excluding the entire `src/jemalloc/test` does not work, unfortunately; there is a file in there that is needed to build libstd. (And anyway there's just 190 KiB uncompressed left in that folder.)

In principle, we could try excluding the Rust test suite directories (that would be `libcore/tests` and `libcollection/tests`). I don't know enough about how this component is used to judge whether that would cause any problems. Anyway this is just 600 KiB uncompressed.

Fixes rust-lang#41952

…r=Mark-Simulacrum

Remove superfluous `;;` sequences

Ran across a doubled `;;` in the docstring for `str::split`. Grep found a few more. :)

…petrochenkov

Fix 'associate type' typo

I came across an error message mentioning an 'associate type'.

Since this is the only instance of this term in rustc (it's 'associated type' everywhere else), I think this might be a typo.

…chton

use shared scripts for init and sccache in cross image

cc rust-lang#42201
cc @malbarbo

Remove stray lockfile

…=Mark-Simulacrum

regression tests for ICEs

closes rust-lang#36379
closes rust-lang#37550
closes rust-lang#37665
closes rust-lang#38160
closes rust-lang#38954
closes rust-lang#39362

r? @Mark-Simulacrum