A lot of bugs are caused by non-exhaustive matching in select statements.
If there is no Case Else one should be added that throws an exception.

Before:

Select Case A
  Case B
    DoSomething
  Case C
    DoSomethingElse
End Select

After:

Select Case A
  Case B
    DoSomething
  Case C
    DoSomethingElse
  Case Else
    Throw New Exception("Unexpected Case")
End Select

Should not raise for boolean if true and false are already handled:

Dim a = True
Select Case a
    Case True
    Case False
End Select

Diagnostic Id: CC0120
Category: Design
Severity: Warning