Why is this an issue?
A chain of If
/ElseIf
statements is evaluated from top to bottom. At most, only one branch will be executed: the first one
with a condition that evaluates to True
.
Therefore, duplicating a condition automatically leads to dead code. Usually, this is due to a copy/paste error. At best, it’s simply dead code and
at worst, it’s a bug that is likely to induce further bugs as the code is maintained, and obviously it could lead to unexpected behavior.
Noncompliant code example
If param = 1 Then
OpenWindow()
ElseIf param = 2 Then
CloseWindow()
ElseIf param = 1 Then ' Noncompliant
MoveWindowToTheBackground()
End If
Compliant solution
If param = 1 Then
OpenWindow()
ElseIf param = 2 Then
CloseWindow()
ElseIf param = 3 Then
MoveWindowToTheBackground()
End If