error[E0255]: the name `A` is defined multiple times
  --> $DIR/issue-19498.rs:3:1
   |
LL | use self::A;
   |     ------- previous import of the module `A` here
LL | use self::B;
LL | mod A {}
   | ^^^^^ `A` redefined here
   |
   = note: `A` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
LL | use self::A as OtherA;
   |             +++++++++

error[E0255]: the name `B` is defined multiple times
  --> $DIR/issue-19498.rs:5:1
   |
LL | use self::B;
   |     ------- previous import of the module `B` here
...
LL | pub mod B {}
   | ^^^^^^^^^ `B` redefined here
   |
   = note: `B` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
LL | use self::B as OtherB;
   |             +++++++++

error[E0255]: the name `D` is defined multiple times
  --> $DIR/issue-19498.rs:9:5
   |
LL |     use C::D;
   |         ---- previous import of the module `D` here
LL |     mod D {}
   |     ^^^^^ `D` redefined here
   |
   = note: `D` must be defined only once in the type namespace of this module
help: you can use `as` to change the binding name of the import
   |
LL |     use C::D as OtherD;
   |              +++++++++

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0255`.