Codecontracts V1.2.30312.0中的错误真实警告 [英] False True Warning from Codecontracts V1.2.30312.0

问题描述

如果您创建一个新的VB.Net Windows窗体项目，并添加以下代码：

Hi,
If you create a new VB.Net Windows Forms Project, and add the following Code:

 

Imports System.Diagnostics.Contracts

Public Class Form1
    Friend WithEvents lv As System.Windows.Forms.ListView
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Dim i As Integer
        Me.lv = New System.Windows.Forms.ListView
        For i = lv.Columns.Count - 1 To 0 Step -1
            Contract.Assume(i < lv.Columns.Count)
            lv.Columns.RemoveAt(i)
            With lv.Columns
                Contract.Assume(i < .Count)
                .RemoveAt(i)
            End With
        Next
    End Sub
End Class

你得到这两个错误的真实警告：

 

You get these two false true warnings:

 

Form1.vb（10,13）：警告：CodeContracts：requires未经证实：index< this.Count
Form1.vb（13,17）：警告：CodeContracts：需要unproven：index< this.Count

Form1.vb(10,13): warning : CodeContracts: requires unproven: index < this.Count
Form1.vb(13,17): warning : CodeContracts: requires unproven: index < this.Count

当我看到第一个时，我认为原因是我通过属性访问了列，但第二个显示情况并非如此。

As I saw the first one, I assumed that the reason was that I accessed the Columns via the property, but the second one shows that's not the case.

推荐答案

看起来System.Windows.Forms.ListView缺少Count == Columns.Count的不变量。  

It looks like System.Windows.Forms.ListView is missing an invariant that Count == Columns.Count.  

此外，您的假设似乎甚至没有生效以抑制丢失的不变量的余量。  绝对是一个错误。

Additionally it seems like your assumes are not even taking effect to suppress the fallout of the missing invariant.  Definitely a bug.

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