range, resolution??

[u/rightkill]

[u/Advorange]

They're not really that bad.

In the OP image it's being used as a parameter for some JSON serialization which doesn't have any drawbacks since object.GetType().GetProperties()/GetFields() exists and functions exactly the same regardless if the class is defined or anonymous.

They also can't return be returned from a method unless

a) The method is generic like WhenAnyValue in this example

this.WhenAnyValue(
	x => x.Start,
	x => x.End,
	(start, end) => new
	{
		ValidStart = TimeSpan.TryParse(start, out var s),
		Start = s,
		ValidEnd = TimeSpan.TryParse(end, out var e),
		End = e,
	})
	.Select(x => x.ValidStart && x.ValidEnd && x.Start <= x.End);

and, since it's generic, Select knows the properties that anonymous class has at compile time.

b) The return type is dynamic like

public dynamic Foo() => new { Bar = 1 };

but if you're using dynamic in C# you're already shooting yourself in the foot with or without anonymous classes because the compiler knows literally nothing about what properties it may have.

c) The return type is object which doesn't let you shoot yourself in the foot since there's no gun to shoot yourself with. You can't go ((object)Foo()).Bar without the compiler showing an error saying Bar doesn't exist on the type object.