One of the links in the docs was being rendered as a literal
open-bracket followed by a single quote, instead of being transformed
into a link. Fix it to match the link earlier in the same paragraph.

This was essentially a "query" previously (with no key, just always run
once when resolving the crate dependencies), and remains so, just now in
a way that isn't on Session. This removes the need for the `Once` as
well.

Similarly to the previous commit, there's no need for this to be in
Session and have a Once around it.

In bootstrap, we set `RUSTC_INSTALL_BINDIR` to `config.bindir`, so
rustdoc can find rustc relative to the toolchain sysroot. However, if a
distro script like Fedora's `%configure` sets an absolute path, then
rustdoc's `sysroot.join(bin_path)` ignores that sysroot altogether.

That would be OK once the toolchain is actually installed, but it breaks
the in-tree doc tests during the build, since `/usr/bin/rustc` is still
the old version. So now we try to make `RUSTC_INSTALL_BINDIR` relative
to the sysroot prefix in the first place.

This makes it easier to add new non-standard constructors, and this also
ensures that we don't forget cases when adding a new constructor.

It counts as an extra constructor for types that are not allowed to be
matched exhaustively.

The single dependency on queries (QueryName) can be fairly easily
abstracted via a trait and this further decouples Session from librustc
(the primary goal).

This helps decouple the lint system from needing the implicit TLS TyCtxt
as well.

Co-Authored-By: Mazdak Farrokhzad <twingoow@gmail.com>

download .tar.xz if python3 is used

fixes rust-lang#65757

Fix documentation for `Iterator::count()`.

The documentation of std::core::Iterator::count() stated that the number returned is the number of times `next` is called on the iterator. However this is not true as the number of times `next` is called is exactly one plus the number returned by `count()`.

…c, r=QuietMisdreavus

rename cfg(rustdoc) into cfg(doc)

Needed by rust-lang#61351

r? @QuietMisdreavus

…-E0623, r=Dylan-DPC

Add long error explanation for E0623

Part of rust-lang#61137.

r? @Dylan-DPC

…sh-link, r=Dylan-DPC

docs: Fix link to BufWriter::flush

One of the links in the docs was being rendered as a literal
open-bracket followed by a single quote, instead of being transformed
into a link. Fix it to match the link earlier in the same paragraph.

…onSapin

add raw ptr variant of UnsafeCell::get

This has come up recently in rust-lang#66051 (Cc @Centril @pitdicker) as well as in discussion with @nikomatsakis and in unrelated discussion with @withoutboats.

add Result::map_or

This PR adds this API to make it consistent with `Option::map_or`.

```rust
impl<T, E> Result<T, E> {
    pub fn map_or<U, F: FnOnce(T) -> U>(self, default: U, f: F) -> U {
        match self {
            Ok(t) => f(t),
            Err(_) => default,
        }
    }
}
```

This API is very small. We already has a similar API for `Option::map_or`.

Add a callback that allows compiler consumers to override queries.

This pull request adds an additional callback that allows compiler consumers such as Prusti and MIRAI to override queries. My hope is that in this way it will be possible to get access to the internal compiler information (e.g. borrow checker) without major changes to the compiler.

This pull request is work in progress because I am still testing if I can get the information which I need.

cc @nikomatsakis

r? @oli-obk

…ulacrum

Use a relative bindir for rustdoc to find rustc

In bootstrap, we set `RUSTC_INSTALL_BINDIR` to `config.bindir`, so
rustdoc can find rustc relative to the toolchain sysroot. However, if a
distro script like Fedora's `%configure` sets an absolute path, then
rustdoc's `sysroot.join(bin_path)` ignores that sysroot altogether.

That would be OK once the toolchain is actually installed, but it breaks
the in-tree doc tests during the build, since `/usr/bin/rustc` is still
the old version. So now we try to make `RUSTC_INSTALL_BINDIR` relative
to the sysroot prefix in the first place.

r? @Mark-Simulacrum

…, r=varkor

Improve non-exhaustiveness handling in usefulness checking

The comments around code paths for the `non_exhaustive` feature mention stuff like "we act as if the type had an extra unmatcheable constructor". So I thought I'd make this explicit by defining a special constructor that does exactly this.
This makes those code paths a bit more legible and less prone to error.

Add some tests for fixed ICEs

Closes rust-lang#30904 (fixed between nightly-2019-07-14 and nightly-2019-07-31)
Closes rust-lang#40231 (example 1 is fixed in 1.32.0, example 2 is fixed in 1.38.0)
Closes rust-lang#52432 (fixed in rustc 1.40.0-beta.1 (76b4053 2019-11-05))
Closes rust-lang#63279 (fixed in rustc 1.40.0-nightly (246be7e 2019-10-25))

r? @Centril

…ochenkov

Move Session fields to CrateStore

`allocator_kind` and `injected_panic_runtime` are both query-like, this moves them out of Session and into CrateStore, avoiding the `Once` they previously had by clearing separating initialization and de-initialization.

…a, r=michaelwoerister

Move self-profile infrastructure to data structures

The single dependency on queries (QueryName) can be fairly easily
abstracted via a trait and this further decouples Session from librustc
(the primary goal).

This is intended as a precursor to moving Session out of librustc, but since that involves lots of smaller steps that move around code I'm splitting it up into separate PRs.

…r=Dylan-DPC

Remove dead code for encoding/decoding lint IDs

This helps decouple the lint system from needing the implicit TLS TyCtxt
as well.