NLL migrate mode: issues two errors for single move out of borrow

[pnkfelix]

This code (play):

struct S;
pub fn main() {
    let x = S;
    let _y = *&x;
}

issues the following diagnostics under migrate mode:

error[E0507]: cannot move out of borrowed content
 --> src/main.rs:4:14
  |
4 |     let _y = *&x;
  |              ^^^
  |              |
  |              cannot move out of borrowed content
  |              help: consider removing the `*`: `&x`

error[E0507]: cannot move out of data in a `&` reference
 --> src/main.rs:4:14
  |
4 |     let _y = *&x;
  |              ^^^
  |              |
  |              cannot move out of data in a `&` reference
  |              cannot move

error: aborting due to 2 previous errors

It issues only a single error under either of AST-borrowck or pure NLL.

[pnkfelix]

(This is obviously one particular instance of #53004)

[pnkfelix]

I think this test:

rust/src/test/ui/by-move-pattern-binding.nll.stderr

Lines 1 to 28 in f99911a

	error[E0507]: cannot move out of borrowed content
	--> $DIR/by-move-pattern-binding.rs:24:11
	|
	LL | match &s.x {
	| ^^^^ cannot move out of borrowed content
	LL | &E::Foo => {}
	LL | &E::Bar(identifier) => f(identifier.clone()) //~ ERROR cannot move
	| -------------------
	| | |
	| | data moved here
	| help: consider removing the `&`: `E::Bar(identifier)`
	|
	note: move occurs because `identifier` has type `std::string::String`, which does not implement the `Copy` trait
	--> $DIR/by-move-pattern-binding.rs:26:17
	|
	LL | &E::Bar(identifier) => f(identifier.clone()) //~ ERROR cannot move
	| ^^^^^^^^^^
	error[E0507]: cannot move out of data in a `&` reference
	--> $DIR/by-move-pattern-binding.rs:26:17
	|
	LL | &E::Bar(identifier) => f(identifier.clone()) //~ ERROR cannot move
	| ^^^^^^^^^^
	| |
	| cannot move out of data in a `&` reference
	| cannot move
	error: aborting due to 2 previous errors

is another instance of this. (But when/if we resolve this, one should double check that claim.)

[pnkfelix]

This is probably fixed by PR #55221

[jonas-schievink]

On current stable and nightly, the code only outputs one diagnostic now (migrate mode is on by default, right?).

[matthewjasper]

Yes, this is fixed.