We don't want these symbols exported from the standard library, this is
just an internal implementation detail of the standard library
currently.

Closes #34984

This hides symbols from various unstable and implementation-detail
crates of the standard library. Although typically transitive exported
`pub extern` functions are exported from cdylibs, these crates aren't
necessary as they're all implementation details.

Closes #34493

These give so many incorrect suggestions that having them is
detrimental to the user experience. The compiler should not be
suggesting changes to the code that are wrong - it is infuriating: not
only is the compiler telling you that _you don't understand_ borrowing,
_the compiler itself_ appears to not understand borrowing. It does not
inspire confidence.

Point to immutable borrow arguments and fields when trying to use them as
mutable borrows. Add label to primary span on "cannot borrow as mutable"
errors.

Present the following output when trying to access an immutable borrow's
field as mutable:

```
error[E0389]: cannot borrow data mutably in a `&` reference
  --> $DIR/issue-38147-1.rs:27:9
   |
26 | fn f(&self) {
   |      -----  use `&mut self` here to make mutable
27 |     f.s.push('x');
   |     ^^^ assignment into an immutable reference
```

And the following when trying to access an immutable struct field as mutable:

```
error: cannot borrow immutable borrowed content `*self.s` as mutable
  --> $DIR/issue-38147-3.rs:17:9
   |
12 |     s: &'a String
   |     ------------- use `&'a mut String` here to make mutable
...|
16 |     fn f(&self) {
   |          -----  use `&mut self` here to make mutable
17 |         self.s.push('x');
   |         ^^^^^^ cannot borrow as mutable
```

The current setup processes impl/trait items while visiting
the impl/trait. This means we basically have this setup:

    <Lots> -> TypeckItemBody(Impl) -> Tables(ImplItem{0,1,2,3})

But this was largely an artifact of the older code. By moving the
processing of items into method dedicated for their use, we produce this
setup:

    <Little> -> TypeckItemBody(ImplItem0) -> Tables(ImplItem0)
    ...
    <Little> -> TypeckItemBody(ImplItem3) -> Tables(ImplItem3)

Fixes #38524

Catches generic types in paths

This is actually kinda hard to hit, but it fixes missing the `foo` in `for _ in foo {}`.

Fixes #36082.

This commit adds a new flag to the configure script,
`--enable-extended`, which is intended for specifying a desire to
compile the full suite of Rust tools such as Cargo, the RLS, etc. This
is also an indication that the build system should create combined
installers such as the pkg/exe/msi artifacts.

Currently the `--enable-extended` flag just indicates that combined
installers should be built, and Cargo is itself not compiled just yet
but rather only downloaded from its location. The intention here is to
quickly get to feature parity with the current release process and then
we can start improving it afterwards.

All new files in this PR inside `src/etc/installer` are copied from the
rust-packaging repository.

* Remove the Reflect trait
* Remove the "reflect" lang feature

rather than "test function", which would be `it_works`

Updated Fuchsia support for std::process. Adds support for try_wait. Misc. updates to reflect changes in Magenta