anchor.diff:              |> Option.defaultValue {
                   IsArm = false
                   IsRef = false
  +                IsBox = false
                   HasMultipleUses = true }
           let isOnlyReference =
               if varAttrs.IsRef then false
  
positive.code: type ScopedVarAttrs = {
      IsArm: bool
      IsRef: bool
      HasMultipleUses: bool
  }
  
  
negative.code: 
      let transformCallee (com: IRustCompiler) ctx calleeExpr =
          let ctx = { ctx with Typegen = { ctx.Typegen with TakingOwnership = false } }
          transformExprMaybeIdentExpr com ctx calleeExpr
  
      let isModuleMember (com: IRustCompiler) (callInfo: Fable.CallInfo) =
          match callInfo.CallMemberInfo with
  