BUG OF THE MONTH | Copy-Paste

V3102 Suspicious access to element of ‘method.SequencePoints’ object by a constant index inside a loop. CodeCoverageMethodTreeNode.cs 52

public override void ActivateItem()
{
  if (method != null && method.SequencePoints.Count > 0) {
    CodeCoverageSequencePoint firstSequencePoint =  
      method.SequencePoints[0];
    ....
    for (int i = 1; i < method.SequencePoints.Count; ++i) {
      CodeCoverageSequencePoint sequencePoint = 
        method.SequencePoints[0];  
      ....
    }
    ....
  }
  ....
}

The zero-index element of the collection is accessed at each iteration of the for loop. I included the code fragment immediately following the condition of the if statement on purpose to show where the line used in the loop body was copied from. The programmer changed the variable name firstSequencePoint to sequencePoint but forgot to change the expression indexing into the elements. This is what the fixed version of the construct looks like:

public override void ActivateItem()
{
  if (method != null && method.SequencePoints.Count > 0) {
    CodeCoverageSequencePoint firstSequencePoint =  
      method.SequencePoints[0];
    ....
    for (int i = 1; i < method.SequencePoints.Count; ++i) {
      CodeCoverageSequencePoint sequencePoint = 
        method.SequencePoints[i];
      ....
    }
    ....
  }
  ....
}

Please click here to see more bugs from this project.