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:15:38
   |
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:15:41
   |
LL |         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
   |                                         ^^^^^^^^^^^^^^^^^^^ assignment in pattern guard

warning[E0510]: cannot assign `x` in match guard
  --> $DIR/borrowck-mutate-in-guard.rs:10:25
   |
LL |     match x {
   |           - value is immutable in match guard
LL |         Enum::A(_) if { x = Enum::B(false); false } => 1,
   |                         ^^^^^^^^^^^^^^^^^^ cannot assign
   |
   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future

warning[E0510]: cannot mutably borrow `x` in match guard
  --> $DIR/borrowck-mutate-in-guard.rs:15:33
   |
LL |     match x {
   |           - value is immutable in match guard
...
LL |         Enum::A(_) if { let y = &mut x; *y = Enum::B(false); false } => 1,
   |                                 ^^^^^^ cannot mutably borrow
   |
   = warning: this error has been downgraded to a warning for backwards compatibility with previous releases
   = warning: this represents potential undefined behavior in your code and this warning will become a hard error in the future

error: aborting due to 3 previous errors

Some errors have detailed explanations: E0301, E0302, E0510.
For more information about an error, try `rustc --explain E0301`.