Why is this an issue?

When you use a using statement, the goal is to ensure the correct disposal of an IDisposable instance when the control leaves the using statement block.

If you return that IDisposable instance inside the block, using will dispose it before the caller can use it, likely causing exceptions at runtime. You should either remove using statement or avoid returning the IDisposable in the using statement block.

How to fix it

Code examples

Noncompliant code example

public FileStream WriteToFile(string path, string text)
{
  using (var fs = File.Create(path)) // Noncompliant: 'fs' is disposed at the end of the using scope
  {
    var bytes = Encoding.UTF8.GetBytes(text);
    fs.Write(bytes, 0, bytes.Length);
    return fs;
  }
}

Compliant solution

public FileStream WriteToFile(string path, string text)
{
  var fs = File.Create(path);
  var bytes = Encoding.UTF8.GetBytes(text);
  fs.Write(bytes, 0, bytes.Length);
  return fs; // Compliant: 'fs' is not disposed once the end of the scope is reached and the caller can use it
}

Resources

Documentation