error: unconstrained opaque type
  --> $DIR/no_inferrable_concrete_type.rs:7:20
   |
LL |     pub type Foo = impl Copy;
   |                    ^^^^^^^^^
   |
   = note: `Foo` must be used in combination with a concrete type within the same module

error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
  --> $DIR/no_inferrable_concrete_type.rs:17:23
   |
LL |     let _: foo::Foo = std::mem::transmute(0u8);
   |                       ^^^^^^^^^^^^^^^^^^^
   |
   = note: source type: `u8` (8 bits)
   = note: target type: `Foo` (size can vary because of [type error])

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0512`.