error[E0391]: cycle detected when computing type of `Foo::T` --> $DIR/issue-34373.rs:7:30 | LL | pub struct Foo>>; | ^^^^^^^^^^ | note: ...which requires expanding type alias `DefaultFoo`... --> $DIR/issue-34373.rs:8:19 | LL | type DefaultFoo = Foo; | ^^^ = note: ...which again requires computing type of `Foo::T`, completing the cycle note: cycle used when collecting item types in top-level module --> $DIR/issue-34373.rs:1:1 | LL | / #![allow(warnings)] LL | | LL | | trait Trait { LL | | fn foo(_: T) {} ... | LL | | fn main() { 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`.