error[E0119]: conflicting implementations of trait `Send` for type `MyStruct`
  --> $DIR/overlap-not-permitted-for-builtin-trait.rs:7:1
   |
LL | impl !Send for MyStruct {}
   | ----------------------- first implementation here
LL | impl !Send for MyStruct {}
   | ^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `MyStruct`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0119`.