Incorrect unused_import lint firing for a function-local macro_rules!

[danielhenrymantilla]

I tried this code:

fn main ()
{
    m!();
    // where
    macro_rules! m {
        () => ();
    } use m;
}

I expected to see this happen: no warning.

Instead, this happened: I get a warning saying:

warning: the item `m` is imported redundantly
 --> src/main.rs:7:11
  |
5 | /     macro_rules! m {
6 | |         () => ();
7 | |     } use m;
  | |     -     ^
  | |_____|
  |       the item `m` is already defined here
  |
  = note: `#[warn(unused_imports)]` on by default

This is incorrect since removing that use "statement" leads to the code not compiling.

Meta

Affects all three versions currently available in the Playground (1.47.0 -> 1.49.0)

[petrochenkov]

This issue no longer reproduces and can be closed when a corresponding test is added.