Why is this an issue?
Conditional expressions which are always true or false can lead to unreachable code.
In the case below, the call of Dispose() never happens.
Dim a = False
If a Then
Dispose() ' Never reached
End If
Exceptions
This rule will not raise an issue in either of these cases:
- When the condition is a single
const bool
Const debug = False
'...
If debug Then
' Print something
End If
- When the condition is the literal
true or false.
In these cases, it is obvious the code is as intended.
How to fix it
The conditions should be reviewed to decide whether:
- to update the condition or
- to remove the condition.
Code examples
Noncompliant code example
Public Sub Sample(ByVal b As Boolean)
Dim a = False
If a Then ' Noncompliant: The true branch is never reached
DoSomething() ' Never reached
End If
If Not a OrElse b Then ' Noncompliant: "not a" is always "True" and the false branch is never reached
DoSomething()
Else
DoSomethingElse() ' Never reached
End If
Dim c = "xxx"
Dim res = If(c, "value") ' Noncompliant: d is always not Nothing, "value" is never used
End Sub
Compliant solution
Public Sub Sample(ByVal b As Boolean)
Dim a = False
If Foo(a) Then ' Condition was updated
DoSomething()
End If
If b Then ' Parts of the condition were removed.
DoSomething()
Else
DoSomethingElse()
End If
Dim c = "xxx"
Dim res = c ' "value" was removed
End Sub
Resources
Documentation
