1 error[E0391]: cycle detected when expanding type alias `X1`
2 --> $DIR/infinite-type-alias-mutual-recursion.rs:1:11
7 note: ...which requires expanding type alias `X2`...
8 --> $DIR/infinite-type-alias-mutual-recursion.rs:3:11
12 note: ...which requires expanding type alias `X3`...
13 --> $DIR/infinite-type-alias-mutual-recursion.rs:4:11
17 = note: ...which again requires expanding type alias `X1`, completing the cycle
18 = note: type aliases cannot be recursive
19 = help: consider using a struct, enum, or union instead to break the cycle
20 = help: see <https://doc.rust-lang.org/reference/types.html#recursive-types> for more information
21 note: cycle used when collecting item types in top-level module
22 --> $DIR/infinite-type-alias-mutual-recursion.rs:1:1
32 error: aborting due to previous error
34 For more information about this error, try `rustc --explain E0391`.