type SafeFn = proc (): void {. raises: [] } proc ok() {. raises: [] .} = discard proc fail() {. raises: [] .} let f1 : SafeFn = ok let f2 : SafeFn = fail # Error: type mismatch: got (proc ()) but expected 'SafeFn = proc (){.closure.}' # .raise effect is 'can raise any' proc fail() = discard