error[E0302]: cannot assign in a pattern guard --> $DIR/borrowck-mutate-in-guard.rs:10:25 | LL | Enum::A(_) if { x = Enum::B(false); false } => 1, | ^^^^^^^^^^^^^^^^^^ assignment in pattern guard error[E0301]: cannot mutably borrow in a pattern guard --> $DIR/borrowck-mutate-in-guard.rs:12:38 | LL | Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1, | ^ borrowed mutably in pattern guard | = help: add #![feature(bind_by_move_pattern_guards)] to the crate attributes to enable error[E0302]: cannot assign in a pattern guard --> $DIR/borrowck-mutate-in-guard.rs:12:41 | LL | Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1, | ^^^^^^^^^^^^^^^^^^^ assignment in pattern guard error: aborting due to 3 previous errors Some errors occurred: E0301, E0302. For more information about an error, try `rustc --explain E0301`.