# Test lambda patterns
let
  # Basic destructuring
  f1 = { a, b }: a + b;

  # With default values
  f2 = { a, b ? 10 }: a + b;

  # With ellipsis (extra fields allowed)
  f3 = { a, ... }: a * 2;

  # Named pattern with ellipsis to allow extra fields
  f4 = arg@{ a, b, ... }: a + b + arg.c;

  # Simple lambda (not a pattern)
  f5 = x: x + 1;
in
  {
    # Test basic destructuring
    test1 = f1 { a = 3; b = 4; };

    # Test with defaults (provide both)
    test2a = f2 { a = 5; b = 6; };

    # Test with defaults (use default for b)
    test2b = f2 { a = 5; };

    # Test ellipsis (extra field ignored)
    test3 = f3 { a = 7; extra = 999; };

    # Test named pattern
    test4 = f4 { a = 1; b = 2; c = 3; };

    # Test simple lambda
    test5 = f5 10;
  }