error[E0308]: mismatched types --> $DIR/closure-print-generic-verbose-2.rs:9:23 | LL | let c = || println!("{} {}", t, x); | -- the found closure LL | let c1 : () = c; | -- ^ expected `()`, found closure | | | expected due to this | = note: expected unit type `()` found closure `[f::{closure#0} closure_substs=(unavailable) substs=[T, _#16t, extern "rust-call" fn(()), _#15t]]` help: use parentheses to call this closure | LL | let c1 : () = c(); | ++ error: aborting due to previous error For more information about this error, try `rustc --explain E0308`.