This reverts commit e38e954.

llvm were not able to optimize the code that well with the simplified mir.

Closes: rust-lang#62993

A program like the following one:

```rust
enum E { A, B, C }
fn f(x: E) -> bool {
    match x {
        A | B => false,
        C => true
    }
}
```

is rejected by the compiler due to `E` variant paths not being in scope.
In this case `A`, `B` are resolved as pattern bindings and consequently
the pattern is considered invalid as the inner or-patterns do not bind
to the same set of identifiers.

This is expected but the compiler errors that follow could be surprising
or confusing to some users. This commit adds a help note explaining that
if the user desired to match against variants or consts, they should use
a qualified path. The note is restricted to cases where the identifier
starts with an upper-case sequence so as to reduce the false negatives.

Since this happens during resolution, there's no clean way to check what
the patterns match against. The syntactic criterium, however, is in line
with the convention that's assumed by the `non-camel-case-types` lint.

Co-Authored-By: Mazdak Farrokhzad <[email protected]>

Adds a closing parenthesis.

Use sharded maps for queries

Based on rust-lang#61779.

r? @gankro

Improve pointer offset method docs

Cc @rkruppe @gnzlbg

Adapt AddRetag for shallow retagging

With rust-lang/miri#872, Miri only retags "bare" references, not those nested in compound types. This adjust `Retag` statement generation to don't emit retags if they are definitely not a bare reference.

I also expanded the mir-opt test to cover the `Retag` in the drop shim, which had previously not been tested.

…es-suggest-qualified-path, r=petrochenkov

Suggest using a qualified path in patterns with inconsistent bindings

A program like the following one:

```rust
enum E { A, B, C }
fn f(x: E) -> bool {
    match x {
        A | B => false,
        C => true
    }
}
```

is rejected by the compiler due to `E` variant paths not being in scope.
In this case `A`, `B` are resolved as pattern bindings and consequently
the pattern is considered invalid as the inner or-patterns do not bind
to the same set of identifiers.

This is expected but the compiler errors that follow could be surprising
or confusing to some users. This commit adds a help note explaining that
if the user desired to match against variants or consts, they should use
a qualified path. The help note is restricted to cases where the identifier
starts with an upper-case sequence so as to reduce the false negatives.

Since this happens during resolution, there's no clean way to check what
it is the patterns match against. The syntactic criterium, however, is in line
with the convention that's assumed by the `non-camel-case-types` lint.

Fixes rust-lang#50831.

… r=matthewjasper

Revert "Simplify MIR generation for logical ops"

This reverts commit e38e954.

llvm were not able to optimize the code that well with the simplified mir.

Closes: rust-lang#62993

resolve: Remove remaining special cases from built-in macros

Edition and definition sites of the macros are now also taken from the `#[rustc_builtin_macro]` definitions in `libcore`.

---
The edition switch may be a breaking change for `Rustc{Encodable,Decodable}` derives if they are used in combination with the unstable crate `serialize` from sysroot like this
```rust
extern crate serialize;
use serialize as rustc_serialize;

#[derive(RustcEncodable)]
struct S;
```
(see the updated `ui-fulldeps` tests).

…iplett

docs: add stdlib env::var(_os) panic

Closes rust-lang#63456

Regression test for rust-lang#56870

Closes rust-lang#56870.

Add tests for issue rust-lang#53598 and rust-lang#57700

Closes rust-lang#53598 and rust-lang#57700

Fixes rust-lang#63477

Adds a closing parenthesis.