error[E0275]: overflow evaluating the requirement `<FooStruct as Foo>::A == _`
  --> $DIR/issue-21946.rs:8:5
   |
LL |     type A = <FooStruct as Foo>::A;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0275`.