region-liveness-drop-no-may-dangle.rs compilation failure on MIR borrowck

[KiChjang]

Compiling with -Zborrowck-mir does not reveal the problem, but compiling with -Znll does:

error[E0597]: borrowed value does not live long enough (Mir)
  --> /home/keith/Workspace/rust/src/test/mir-opt/nll/region-liveness-drop-no-may-dangle.rs:26:51
   |
25 |     let mut v = [1, 2, 3];
   |         ----- temporary value created here
26 |     let p: Wrap<& /* R1 */ usize> = Wrap { value: &v[0] };
   |                                                   ^^^^^ temporary value dropped here while still borrowed
   |
   = note: consider using a `let` binding to increase its lifetime

@arielb1 said that this is due to us having an incorrect MIR borrowck before, and this should really throw a compilation error as seen.

Temporarily disabling this test in order to land my patch at #46100.

cc @nikomatsakis @arielb1 @pnkfelix

[KiChjang]

Possibly related to #45537.

[nikomatsakis]

@arielb1 can you elaborate on why you think that this test ought to report a compilation error? I don't understand why that is true.

(Among other things, the code does compile today -- i.e., without NLL etc.)

[arielb1]

@nikomatsakis

The test is not supposed to cause a compilation error. The bug is that the test fails to compile with -Z nll.

[nikomatsakis]

Fixed

[pnkfelix]

Wait a minute: does this test work or not? Has it been reenabled on master yet? Is there a latent bug in NLL still?

[matthewjasper]

The test was reenabled in #46320.

[pnkfelix]

Thanks @matthewjasper sorry for the noise,