impl block on a type defined with type_alias_impl_trait can conflict with other unrelated impl

I tried this code:

#![feature(type_alias_impl_trait)]

use std::any::TypeId;

pub trait Trait {}
impl<T: ?Sized> Trait for T {}

pub trait Other {}

macro_rules! mymac {
    () => {{
        struct S;
        type Foo = impl Trait;
        let x: Foo = S;
        println!("{:?}", TypeId::of::<Foo>());
        impl Foo {
            fn foo() -> () {}
        }
        impl Other for Foo {}
    }};
}

fn main() {
    mymac!();
    mymac!();
}

I expected to see this happen: compiles without error

Instead, this happened:

error[E0119]: conflicting implementations of trait `Other` for type `main::Foo`
  --> src/main.rs:19:9
   |
19 |         impl Other for Foo {}
   |         ^^^^^^^^^^^^^^^^^^
   |         |
   |         first implementation here
   |         conflicting implementation for `main::Foo`
...
25 |     mymac!();
   |     -------- in this macro invocation
   |
   = note: this error originates in the macro `mymac` (in Nightly builds, run with -Z macro-backtrace for more info)

Meta

Rust nightly version on the playground as of 9th of April 2025.

Start by reproducing the supplied src/main.rs on the stated Rust nightly, focusing on the two mymac! invocations and the conflicting Other implementation diagnostic. Done means the reproducer compiles without treating the two macro expansions as the same Foo, with coverage for this case.