   mutating func bar()
   mutating func bas()
 
-  prefix func +(x: Self)
-
   var prop1: Int { get set }
   var prop2: Int { get set }
   var prop3: Int { get nonmutating set }

    set {}
  }
}

prefix func +(x: C) {}

  // CHECK-NOT:     destroy_addr [[SELF_ADDR]]
}

// Witness thunk for nonmutating 'foo'
// CHECK-LABEL: sil hidden @_TTWV15guaranteed_self1SS_7FooableS_FS1_3fooUS1___fQPS1_FSiT_ : $@cc(witness_method) @thin (Int, @in_guaranteed S) -> () {
// CHECK:       bb0({{.*}} [[SELF_ADDR:%.*]] : $*S):
