S3010 — Static fields should not be updated in constructors

Why is this an issue?

Assigning a value to a static field in a constructor could cause unreliable behavior at runtime since it will change the value for all instances of the class.

Instead remove the field’s static modifier, or initialize it statically.

Noncompliant code example

public class Person
{
  private static DateTime dateOfBirth;
  private static int expectedFingers;

  public Person(DateTime birthday)
  {
    dateOfBirth = birthday;  // Noncompliant; now everyone has this birthday
    expectedFingers = 10;  // Noncompliant
  }
}

Compliant solution

public class Person
{
  private DateTime dateOfBirth;
  private static int expectedFingers = 10;

  public Person(DateTime birthday)
  {
    this.dateOfBirth = birthday;
  }
}