error[E0275]: overflow normalizing the type alias `X2`
  --> $DIR/infinite-type-alias-mutual-recursion.rs:6:1
   |
LL | type X1 = X2;
   | ^^^^^^^
   |
   = note: in case this is a recursive type alias, consider using a struct, enum, or union instead

error[E0275]: overflow normalizing the type alias `X3`
  --> $DIR/infinite-type-alias-mutual-recursion.rs:9:1
   |
LL | type X2 = X3;
   | ^^^^^^^
   |
   = note: in case this is a recursive type alias, consider using a struct, enum, or union instead

error[E0275]: overflow normalizing the type alias `X1`
  --> $DIR/infinite-type-alias-mutual-recursion.rs:11:1
   |
LL | type X3 = X1;
   | ^^^^^^^
   |
   = note: in case this is a recursive type alias, consider using a struct, enum, or union instead

error: aborting due to 3 previous errors

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