error[E0391]: cycle detected when computing the super predicates of `T1`
  --> $DIR/issue-12511.rs:1:12
   |
LL | trait T1 : T2 {
   |            ^^
   |
note: ...which requires computing the super predicates of `T2`...
  --> $DIR/issue-12511.rs:5:12
   |
LL | trait T2 : T1 {
   |            ^^
   = note: ...which again requires computing the super predicates of `T1`, completing the cycle
note: cycle used when checking that `T1` is well-formed
  --> $DIR/issue-12511.rs:1:1
   |
LL | / trait T1 : T2 {
LL | |
LL | | }
   | |_^
   = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0391`.