$ rustc main.rs error[E0573]: expected type, found local variable `b` --> main.rs:5:25 | 5 | fn no_bound(b: Inv<(b)>); | ^ not a type thread 'rustc' panicked at 'expected `NodeId` to be lowered already for res Local( NodeId(21), )', src/librustc_ast_lowering/lib.rs:662:17 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace error: internal compiler error: unexpected panic note: the compiler unexpectedly panicked. this is a bug. note: we would appreciate a bug report: https://github.com/rust-lang/rust/blob/master/CONTRIBUTING.md#bug-reports note: rustc 1.43.0-nightly (5d04ce67f 2020-02-13) running on x86_64-unknown-linux-gnu error: aborting due to previous error For more information about this error, try `rustc --explain E0573`.