extern crate peg; peg::parser!(grammar foo() for str { rule rec() = rec() //~ ERROR left recursive rules create an infinite loop: rec -> rec rule foo() = "foo" foo() / bar() //~ ERROR left recursive rules create an infinite loop: bar -> foo -> bar rule bar() = "bar" bar() / foo() //~ ERROR left recursive rules create an infinite loop: foo -> bar -> foo rule prec() = precedence! { prec() { () } //~ ERROR } }); fn main() {}