Rollup of 5 pull requests

Successful merges:

 - #70345 (Remove `no_integrated_as` mode.)
 - #70434 (suggest `;` on expr `mac!()` which is good as stmt `mac!()`)
 - #70457 (non-exhastive diagnostic: add note re. scrutinee type)
 - #70478 (Refactor type_of for constants)
 - #70480 (clarify hir_id <-> node_id method names)

Failed merges:

r? @ghost

clarify hir_id <-> node_id method names

resolves 2 FIXME.

r? @EddyB

Refactor type_of for constants

If I have to look at this function for a few hours I want it to at least look good.

r? @varkor

non-exhastive diagnostic: add note re. scrutinee type

This fixes https://github.com/rust-lang/rust/issues/67259 by adding a note:
```
    = note: the matched value is of type &[i32]
```
to non-exhaustive pattern matching errors.

r? @varkor @estebank

suggest `;` on expr `mac!()` which is good as stmt `mac!()`

Fixes https://github.com/rust-lang/rust/issues/34421 by implementing @jseyfried's suggestion in https://github.com/rust-lang/rust/issues/34421#issuecomment-301578683.

r? @petrochenkov

Remove `no_integrated_as` mode.

Specifically, remove both `-Z no_integrated_as` and
`TargetOptions::no_integrated_as`. The latter was only used for the
`msp430_none_elf` platform, for which it's no longer required.

r? @alexcrichton

Move the query system to a dedicated crate

The query system `rustc::ty::query` is split out into the `rustc_query_system` crate.

Some commits are unformatted, to ease rebasing.

Based on #67761 and #69910.

r? @Zoxc

Rollup of 4 pull requests

Successful merges:

 - #65222 (Proposal: `fold_self` and `try_fold_self` for Iterators)
 - #69887 (clean up E0404 explanation)
 - #70068 (use "gcc" instead of "cc" on *-sun-solaris systems when linking)
 - #70470 (Clean up E0463 explanation)

Failed merges:

r? @ghost

Clean up E0463 explanation

r? @Dylan-DPC

use "gcc" instead of "cc" on *-sun-solaris systems when linking

On illumos and Solaris systems, Rust will use GCC as the link editor.
Rust does this by invoking "cc", which on many (Linux and perhaps BSD)
systems is generally either GCC or a GCC-compatible front-end.  On
historical Solaris systems, "cc" was often the Sun Studio compiler.
This history casts a long shadow, and as such, even most modern
illumos-based operating systems tend to install GCC as "gcc", without
also making it available as "cc".

We should invoke GCC as "gcc" on such systems to ensure we get the right
compiler driver.

clean up E0404 explanation

r? @Dylan-DPC

Proposal: `fold_self` and `try_fold_self` for Iterators

This pull request proposes & implements two new methods on Iterators: `fold_self` and `try_fold_self`. These are variants of `fold` and `try_fold` that use the first element in the iterator as the initial accumulator.

Let me know if a public feature like this requires an RFC, or if this pull request is sufficient as place for discussion.

Enable blessing of mir opt tests

cc @rust-lang/wg-mir-opt
cc @RalfJung

Long overdue, but now you can finally just add a

```rust
// EMIT_MIR rustc.function_name.MirPassName.before.mir
```

(or `after.mir` since most of the time you want to know the MIR after a pass). A `--bless` invocation will automatically create the files for you.

I suggest we do this for all mir opt tests that have all of the MIR in their source anyway

If you use `rustc.function.MirPass.diff` you only get the diff that the MIR pass causes on the MIR.

Fixes #67865

Test and fix gdb pretty printing more

Over time I had oversimplified the test case for #68098: it does not have an internal node to print so it did not test what it pretended to test. And then I also realized not spotting the same mistake reviewing #70111, and more likely to occur in the wild. Now, both test cases fail if you put back the flawed python code.

r? @Mark-Simulacrum

Upgrade rustc and bootstrap dependencies

Rename asm! to llvm_asm!

As per https://github.com/rust-lang/rfcs/pull/2843, this PR renames `asm!` to `llvm_asm!`. It also renames the compiler's internal `InlineAsm` data structures to `LlvmInlineAsm` in preparation for the new `asm!` functionality specified in https://github.com/rust-lang/rfcs/pull/2850.

This PR doesn't actually deprecate `asm!` yet, it just makes it redirect to `llvm_asm!`. This is necessary because we first need to update the submodules (in particular stdarch) to use `llvm_asm!`.

Specifically, remove both `-Z no_integrated_as` and
`TargetOptions::no_integrated_as`. The latter was only used for the
`msp430_none_elf` platform, for which it's no longer required.

Rollup of 5 pull requests

Successful merges:

 - #69644 (Remove framework in `dataflow/mod.rs` in favor of "generic" one)
 - #69936 (Fix cycle error when emitting suggestion for mismatched `fn` type)
 - #70048 (Allow obtaining &mut OsStr)
 - #70344 (Decouple `rustc_hir::print` into `rustc_hir_pretty`)
 - #70435 (Add regression test for #66706)

Failed merges:

r? @ghost

Add regression test for #66706

Adds the two cases that no longer ICE (https://github.com/rust-lang/rust/issues/66706#issuecomment-604098436)

Decouple `rustc_hir::print` into `rustc_hir_pretty`

High level summary:
- The HIR pretty printer, `rustc_hir::print` is moved into a new crate `rustc_hir_pretty`.
- `rustc_ast_pretty` and `rustc_errors` are dropped as `rustc_hir` dependencies.
- The dependence on HIR pretty is generally reduced, leaving `rustc_save_analysis`, `rustdoc`, `rustc_metadata`, and `rustc_driver` as the remaining clients.

The main goal here is to reduce `rustc_hir`'s dependencies and its size such that it can start and finish earlier, thereby working towards https://github.com/rust-lang/rust/issues/65031.

r? @Zoxc

Allow obtaining &mut OsStr

```rust
impl DerefMut for OsString {...}              // type Target = OsStr
impl IndexMut<RangeFull> for OsString {...}   // type Output = OsStr
```

---

This change is pulled out of #69937 per @dtolnay

This implements `DerefMut for OsString` to allow obtaining a `&mut OsStr`. This also implements `IndexMut for OsString`, which is used by `DerefMut`. This pattern is the same as is used by `Deref`.

This is necessary to for methods like `make_ascii_lowercase` which need to mutate the underlying value.

Fix cycle error when emitting suggestion for mismatched `fn` type

Fixes #66667

Previously, we called `tcx.typeck_tables_of` when determining whether or
not to emit a suggestion for a type error. However, we might already be
type-checking the `DefId` we pass to `typeck_tables_of` (it could be
anywhere in the query stack).

Fortunately, we only need the function signature, not the entire
`TypeckTables`. By using `tcx.fn_sig`, we avoid the possibility of cycle
errors while retaining the ability to emit a suggestion.

Remove framework in `dataflow/mod.rs` in favor of "generic" one

This is the culmination of the work described in rust-lang/compiler-team#202. All dataflow analyses (including the one in `clippy`) have been ported to use the framework in `dataflow/generic`, which can efficiently handle both gen/kill and generic problems. This PR moves the framework in `dataflow/generic` to `dataflow/framework`, and removes the gen/kill framework in `dataflow/mod.rs`.

More comprehensive documentation for the new framework is tracked in rust-lang/rustc-guide#564.

`clippy` will need to change the path it uses to import the dataflow analysis traits.