error[E0391]: cycle detected when evaluating type-level constant --> $DIR/const-size_of-cycle.rs:4:17 | LL | bytes: [u8; std::mem::size_of::()] | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | note: ...which requires const-evaluating + checking `Foo::bytes::{constant#0}`... --> $DIR/const-size_of-cycle.rs:4:17 | LL | bytes: [u8; std::mem::size_of::()] | ^^^^^^^^^^^^^^^^^^^^^^^^^^ note: ...which requires const-evaluating + checking `Foo::bytes::{constant#0}`... --> $DIR/const-size_of-cycle.rs:4:17 | LL | bytes: [u8; std::mem::size_of::()] | ^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: ...which requires computing layout of `Foo`... = note: ...which requires computing layout of `[u8; std::mem::size_of::()]`... = note: ...which requires normalizing `[u8; std::mem::size_of::()]`... = note: ...which again requires evaluating type-level constant, completing the cycle note: cycle used when checking that `Foo` is well-formed --> $DIR/const-size_of-cycle.rs:3:1 | LL | struct Foo { | ^^^^^^^^^^ = 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 previous error For more information about this error, try `rustc --explain E0391`.