Examples of errors detected by the V3202 diagnostic

V3202. Unreachable code detected. The 'case' value is out of the range of the match expression.

.NET 9

V3202 Unreachable code detected. The 'case' value is out of range of the match expression. VBCodeGenerator.cs 580

public enum MemberAttributes
{
  Abstract = 0x0001,
  Final = 0x0002,
  Static = 0x0003,
  Override = 0x0004,
  Const = 0x0005,
  New = 0x0010,
  Overloaded = 0x0100,
  Assembly = 0x1000,
  FamilyAndAssembly = 0x2000,
  Family = 0x3000,
  FamilyOrAssembly = 0x4000,
  Private = 0x5000,
  Public = 0x6000,
  AccessMask = 0xF000,
  ScopeMask = 0x000F,
  VTableMask = 0x00F0
}

protected override void OutputMemberScopeModifier(MemberAttributes attributes)
{
  switch (attributes & MemberAttributes.ScopeMask)
  {
    case MemberAttributes.Abstract:
      Output.Write("MustOverride ");
      break;
    case MemberAttributes.Final:
      Output.Write("");
      break;
    ....
    case MemberAttributes.Private:            // <=
      Output.Write("Private ");
      break;
    ....
  }
}

ScottPlot

V3202 Unreachable code detected. The 'case' value is out of range of the match expression. ScottPlot.WinForms FormsPlotExtensions.cs 106

public static Interactivity.Key GetKey(this Keys keys)
{

  Keys keyCode = keys & ~Keys.Modifiers;                   // <=
  Interactivity.Key key = keyCode switch
  {
    Keys.Alt => Interactivity.StandardKeys.Alt,            // <=
    Keys.Menu => Interactivity.StandardKeys.Alt,
    Keys.Shift => Interactivity.StandardKeys.Shift,        // <=
    Keys.ShiftKey => Interactivity.StandardKeys.Shift,
    Keys.LShiftKey => Interactivity.StandardKeys.Shift,
    Keys.RShiftKey => Interactivity.StandardKeys.Shift,
    Keys.Control => Interactivity.StandardKeys.Control,    // <=
    Keys.ControlKey => Interactivity.StandardKeys.Control,
    Keys.Down => Interactivity.StandardKeys.Down,
    Keys.Up => Interactivity.StandardKeys.Up,
    Keys.Left => Interactivity.StandardKeys.Left,
    Keys.Right => Interactivity.StandardKeys.Right,
    _ => Interactivity.StandardKeys.Unknown,
  };

  ....
}

[Flags]
[TypeConverter(typeof(KeysConverter))]
[Editor(....)]
public enum Keys
{
  Modifiers = unchecked((int)0xFFFF0000),

  ....

  Shift = 0x00010000,
  Control = 0x00020000,
  Alt = 0x00040000
}