error[E0391]: cycle detected when const-evaluating + checking `Foo::bytes::{{constant}}#0` --> $DIR/const-size_of-cycle.rs:6:17 | LL | bytes: [u8; std::mem::size_of::()] | ^^^^^^^^^^^^^^^^^^^^^^^^^^ | note: ...which requires const-evaluating `Foo::bytes::{{constant}}#0`... --> $SRC_DIR/libcore/mem.rs:LL:COL | LL | intrinsics::size_of::() | ^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: ...which requires computing layout of `Foo`... = note: ...which requires normalizing `ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All, def_id: None }, value: [u8; _] }`... note: ...which requires const-evaluating + checking `Foo::bytes::{{constant}}#0`... --> $DIR/const-size_of-cycle.rs:6:17 | LL | bytes: [u8; std::mem::size_of::()] | ^^^^^^^^^^^^^^^^^^^^^^^^^^ = note: ...which again requires const-evaluating + checking `Foo::bytes::{{constant}}#0`, completing the cycle note: cycle used when processing `Foo` --> $DIR/const-size_of-cycle.rs:5:1 | LL | struct Foo { | ^^^^^^^^^^ error: aborting due to previous error For more information about this error, try `rustc --explain E0391`.