Tait fails when type alias inside the adjacent function

I tried this code:
playground

#![feature(type_alias_impl_trait)]

type Foo = impl Sized;

#[define_opaque(Foo)]
fn foo() -> Foo {
    0i32
}

fn bar() {
    type Bar = Foo;
}

fn main() {}

I expected to see this happen: code checks, just like this one (type alias moved out from the function):

#![feature(type_alias_impl_trait)]

type Foo = impl Sized;

#[define_opaque(Foo)]
fn foo() -> Foo {
    0i32
}

type Bar = Foo;

fn bar() {}

fn main() {}

Instead, this happened:

error: item does not constrain `Foo::{opaque#0}`
  --> src/main.rs:10:4
   |
10 | fn bar() {
   |    ^^^
   |
   = note: consider removing `#[define_opaque]` or adding an empty `#[define_opaque()]`
note: this opaque type is supposed to be constrained
  --> src/main.rs:3:12
   |
 3 | type Foo = impl Sized;
   |            ^^^^^^^^^^

error: could not compile `play` (bin "play") due to 1 previous error

Meta

rustc --version --verbose:

> rustc --version --verbose
rustc 1.93.0-nightly (adaa83897 2025-10-27)
binary: rustc
commit-hash: adaa838976ff99a4f0661136322f64cb466b58a0
commit-date: 2025-10-27
host: x86_64-unknown-linux-gnu
release: 1.93.0-nightly
LLVM version: 21.1.3

Start with the linked Rust Playground reproducer and compare the failing local type-alias case with the working top-level alias case. Trace the compiler handling for #[define_opaque(Foo)] and local aliases; done means the failing example checks without producing the item does not constrain error.