item paths use the name of the item, which might differ from the name of the import

STR

Crate foo:

mod internal {
    pub struct S;
}

pub use internal::S as T;

Crate main:

extern crate foo;

fn main() {
    foo::T
}

Results

error[E0308]: mismatched types
 --> x.rs:4:5
  |
3 | fn main() {
  |           - expected `()` because of default return type
4 |     foo::T
  |     ^^^^^^ expected (), found struct `foo::S`
  |
  = note: expected type `()`
             found type `foo::S`

error: aborting due to previous error

The error message refers to foo::S, which does not exist (only foo::T does)

1. On today's rustc, the message is even a little more confusing (at least, if the type comes from the same crate, haven't tried it outside of the playground yet):

   mod krate {
       mod internal {
           pub struct S;
       }
       
       pub use self::internal::S as T;
   }
   
   fn main() {
       krate::T
   }
   

   error[E0308]: mismatched types
     --> src/main.rs:10:5
      |
   9  | fn main() {
      |           - expected `()` because of default return type
   10 |     krate::T
      |     ^^^^^^^^ expected `()`, found struct `S`
   

   It doesn't even give a full path for the S type.

   Playground

   Potentially related: https://github.com/rust-lang/rust/issues/44478

   Ben Reeves at 2021-12-29 04:26:34