Variable declared but never used (CS0168)

Key dotnet.codequality.unused-variable · Severity warning · Category codequality

C# compiler warning CS0168. Flags a local variable - often a catch variable - that is declared and never used.

Incorrect

try
{
    Save();
}
catch (DbUpdateException ex)
{
    return Conflict();
}

Correct

try
{
    Save();
}
catch (DbUpdateException)
{
    return Conflict();
}