# Conflicts:
#	src/librustc_mir/build/scope.rs

see rust-lang/rfcs#2043 for details

The motivation here is to allow rustfmt to recover from parse errors
after failing to parse macros.

This commit fixes procedural macro attributes being attached to trait methods,
ensuring that they get resolved and expanded as other procedural macro
attributes. The bug here was that `current_module` on the resolver was
accidentally set to be a trait when it's otherwise only ever expecting a
`mod`/block module. The actual fix here came from @jseyfried, I'm just helping
to land it in the compiler!

Closes rust-lang#42493

distcheck complains that this file references projects not cotnained in the tarball

The previous documentation mentioned this, but ambiguously used the term "fail".

This clarifies that the function will panic if the index is out of bounds, instead of silently failing and not doing anything.

After a projection was processed, its derived subobligations no longer
need any processing when encountered, and can be removed. This improves
the status of rust-lang#43787.

This is actually complementary to rust-lang#43938 - that PR fixes selection
caching (and @remram44's example, which "accidentally" worked because of
the buggy projection caching) while this PR fixes projection caching

Make the ./x.py script fail when run with an invalid command, like:

  ./x.py nonsense

This helps in case of chaining multiple runs, eg.:

  ./x.py biuld && ./x.py test

This commit rewrites our ancient `./configure` script from shell into Python.
The impetus for this change is to remove `config.mk` which is just a vestige of
the old makefile build system at this point. Instead all configuration is now
solely done through `config.toml`.

The python script allows us to more flexibly program (aka we can use loops
easily) and create a `config.toml` which is based off `config.toml.example`.
This way we can preserve comments and munge various values as we see fit.

It is intended that the configure script here is a drop-in replacement for the
previous configure script, no functional change is intended. Also note that the
rationale for this is also because our build system requires Python, so having a
python script a bit earlier shouldn't cause too many problems.

Closes rust-lang#40730

The crate itself is internally referenced by serde_derive.

…rk-Simulacrum

rustbuild: Rewrite the configure script in Python

This commit rewrites our ancient `./configure` script from shell into Python.
The impetus for this change is to remove `config.mk` which is just a vestige of
the old makefile build system at this point. Instead all configuration is now
solely done through `config.toml`.

The python script allows us to more flexibly program (aka we can use loops
easily) and create a `config.toml` which is based off `config.toml.example`.
This way we can preserve comments and munge various values as we see fit.

It is intended that the configure script here is a drop-in replacement for the
previous configure script, no functional change is intended. Also note that the
rationale for this is also because our build system requires Python, so having a
python script a bit earlier shouldn't cause too many problems.

Closes rust-lang#40730
Closes rust-lang#43295
Closes rust-lang#42255
Closes rust-lang#38058
Closes rust-lang#32176

There were several feature-gated attributes for which the
feature-not-available error spans would point to the item annotated with
the gated attribute, when it would make more sense for the span to point
to the attribute itself: if the attribute is removed, the
function/struct/&c. likely still makes sense and the program will
compile. (Note that we decline to make the analogous change for the
`main`, `start`, and `plugin_registrar` features, for in those cases it
makes sense for the span to implicate the entire function, of which
there is little hope of using without the gated attribute.)

This commit introduces the ability to create and emit `Diagnostic`
structures from proc-macros, allowing for proc-macro authors to emit
warning, error, note, and help messages just like the compiler does.

Clarify that VecDeque::swap can panic

The previous documentation mentioned this, but ambiguously used the term "fail".

This clarifies that the function will panic if the index is out of bounds, instead of silently failing and not doing anything.

If there's anything else I can do to improve this PR, I'd be happy to do so! Just saw this when reading through the docs in passing - it was slightly unclear what "fail" meant.

in particular:

* show how to create an iterator that yields multiple socket addresses
* show more failing scenarios

Brings in a few fixes for wasm/asmjs

This commit flags all allocation-related functions in liballoc as "this can't
unwind" which should largely resolve the size-related issues found on rust-lang#42808.
The documentation on the trait was updated with such a restriction (they can't
panic) as well as some other words about the relative instability about
implementing a bullet-proof allocator.

Closes rust-lang#42808

…lean slate

Generator support

This adds experimental support for generators intended to land once rust-lang/rfcs#2033 is approved.

This is not yet ready to be merged. Things to do:
- [x] Make closure arguments on generators an error
- [x] Spot FIXMEs
- [x] Pass make tidy
- [x] Write tests
- [x] Document the current syntax and semantics for generators somewhere
- [x] Use proper error message numbers
- [x] ~~Make the implicit argument type default to `()`~~

…akis

clear out projection subobligations after they are processed

After a projection was processed, its derived subobligations no longer
need any processing when encountered, and can be removed. This improves
the status of rust-lang#43787.

This is actually complementary to rust-lang#43938 - that PR fixes selection
caching (and @remram44's example, which "accidentally" worked because of
the buggy projection caching) while this PR fixes projection caching.

r? @nikomatsakis

…urntSushi

std: Mark allocation functions as nounwind

This commit flags all allocation-related functions in liballoc as "this can't
unwind" which should largely resolve the size-related issues found on rust-lang#42808.
The documentation on the trait was updated with such a restriction (they can't
panic) as well as some other words about the relative instability about
implementing a bullet-proof allocator.

Closes rust-lang#42808

When we pass `--host` the `self.hosts` array doesn't contain `self.build`, so
check `self.build` to see if we can uplift.

No need to depend on librustc! All we need is libstd

Closes rust-lang#44140

…ified by the end, use the channel to determine its value

Suggest `Ok(())` when encountering `Result::<(), E>::Ok()`

…=nikomatsakis

feature error span on attribute for fn_must_use, SIMD/align reprs, macro reëxport

There were several feature-gated attributes for which the feature-not-available
error spans would point to the item annotated with the gated attribute, when it
would make more sense for the span to point to the attribute itself: if the
attribute is removed, the function/struct/_&c._ likely still makes sense and the
program will compile. (Note that we decline to make the analogous change for
the `main`, `start`, and `plugin_registrar` features, for in those cases it
makes sense for the span to implicate the entire function, of which there is
little hope of using without the gated attribute.)

![feature_attr_error_span](https://user-images.githubusercontent.com/1076988/29746531-fd700bfe-8a91-11e7-9c5b-6f5324083887.png)

This allows caching closure signatures and kinds in the normal selection
and evaluation caches, and fixes the exponential worst-case in
@remram44's example, which is a part of rust-lang#43787.

This improvement is complenentary to rust-lang#43999 - they fix different cases.

At least, I think that's how it should be.  'debug' is how the feature is called in Cargo.toml.

This commit removes the `specialization_cache` field of `TyCtxt` by moving it to
a dedicated query, which it turned out was already quite easily structured to do
so!

the data serves no purpose - it can be recovered from the obligation -
and I think may leak stale inference variables into global caches.

Fixes rust-lang#43420.