anchor.diff:          check environ
               (freshNode <| BopExpr(And, freshNode <| BopExpr(Or, freshNode True, freshNode True), freshNode False))
               (BFalse : BoolExpr<Sym<Var>>)
  +
   
   module VarLists =
       let checkFail (vars : TypedVar list) (expectedErrs : VarMapError list) =
  
positive.code:             // TODO (CaptainHayashi): this shouldn't be optimised?
              (IInt 5L)
  
  module BooleanExprs =
      let check (env : VarMap) (ast : Expression) (expectedExpr : BoolExpr<Sym<Var>>) =
          let actualBoolExpr = okOption <| modelBoolExpr env environ id ast
  
negative.code:     { ViewProtos = ticketLockProtos
        SharedVars = shared
        ThreadVars = environ }
  
  
  module ViewPass =
      let check (view : View) (expectedCView : CView) =
  