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