Code inspection: Merge null/pattern checks into complex pattern

tip

You can suppress this inspection to ignore specific issues, change its severity level to make the issues less or more noticeable, or disable it altogether.

This inspection suggests using list pattern syntax introduced in C# 11.

Before the introduction of this syntax, it was generally necessary to check the length of the collection and then use indexer access expressions to check the items in the collection. This inspection identifies such checks in your code and suggests replacing them with more concise list pattern matching.

static void Main(string[] args)
{
  if (args is ["--help", _] && args[1] is var topic)
  {
    Console.WriteLine($"Help on topic '{topic}':");
  }
}

static void Main(string[] args)
{
  if (args is ["--help", var topic])
  {
    Console.WriteLine($"Help on topic '{topic}':");
  }
}

note

This inspection suggests that you use a C# 11 feature.

By default, JetBrains Rider automatically detects C# version based on the associated compiler. However, you can specify the target C# version explicitly for a project — press AltEnter on the project in the Solution Explorer and use the Language version selector on the Application page of the Project Properties dialog .

To set the C# version for all projects in your solution, specify it in a Directory.Build.props file in your solution directory as described here.