Auto merge of #41236 - cengizIO:master, r=nikomatsakis

Move E0101 and E0102 logic into new E0282 mechanism #40013

Hello there!

## What's this?
Previously, me and @nikomatsakis worked on error messages of uninferred locals. (#38812)

This aims to build up on that by moving certain type checks from `writeback`.

With this, `E0101` and `E0102` errors are getting obsoleted and no longer thrown.

They're replaced with customized versions of `E0282`s instead.

## Sample Error Messages

#### `E0101` is getting converted into:
```rust
error[E0282]: type annotations needed
 --> test.rs:2:14
  |
2 |     let x = |_| {};
  |              ^ consider giving this closure parameter a type

error: aborting due to previous error
```

#### `E0102` is getting converted into:
```rust
error[E0282]: type annotations needed
 --> test.rs:2:9
  |
2 |     let x = [];
  |         ^
  |         |
  |         consider giving `x` a type
  |         cannot infer type for `[_; 0]`

error: aborting due to previous error
```

## Annoyances
- I think we need to change our way of type name resolving in relevant places, because that `[_; 0]` looks horrible IMHO.
- I'm not terribly happy with the note ordering of errors. So please do point to code that might help me accomplish this.

## Tests
Tests of `E0101` and `E0102` are getting converted from `compile-fail` to `ui` tests.

## Documentation
Please help me with documentation update. There are some confusing places that needed an update but I'm not sure if I did the right ones.

Please do comment on messages, layouts and other details.

## Appreciation
Huge thanks goes to @nikomatsakis for being a patient and humble mentor along this long journey. 🍻

src/test/compile-fail/E0101.rs

@@ -1,15 +0,0 @@
-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-fn main() {
-    let x = |_| {};
-    //~^ ERROR E0101
-    //~| NOTE cannot resolve type of expression
-}

src/test/compile-fail/E0102.rs

@@ -1,16 +0,0 @@
-// Copyright 2016 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-fn main() {
-    let x = [];
-    //~^ ERROR type annotations needed
-    //~| NOTE consider giving `x` a type
-    //~| NOTE cannot infer type for `_`
-}

src/test/compile-fail/issue-12187-1.rs

@@ -16,5 +16,5 @@ fn main() {
     let &v = new();
     //~^ ERROR type annotations needed [E0282]
     //~| NOTE cannot infer type for `_`
-    //~| NOTE consider giving a type to pattern
+    //~| NOTE consider giving the pattern a type
 }

src/test/compile-fail/issue-12187-2.rs

@@ -16,5 +16,5 @@ fn main() {
     let &v = new();
     //~^ ERROR type annotations needed [E0282]
     //~| NOTE cannot infer type for `_`
-    //~| NOTE consider giving a type to pattern
+    //~| NOTE consider giving the pattern a type
 }

src/test/compile-fail/issue-22897.rs

@@ -1,19 +0,0 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-fn main() { }
-
-// Before these errors would ICE as "cat_expr Errd" because the errors
-// were unknown when the bug was triggered.
-
-fn unconstrained_type() {
-    [];
-    //~^ ERROR cannot determine a type for this expression: unconstrained type
-}