What does this notation involving angle brackets mean? [duplicate]

Question

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Where to learn about VS debugger 'magic names' (1 answer)

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I'm reading Async in C# 5.0, and the section on the compiler transform contains this snippet:

public Task<int> AlexsMethod()
{
    <AlexsMethod>d__0 stateMachine = new <AlexsMethod>d__0();
    stateMachine.<>4__this = this;
    stateMachine.<>t__builder = AsyncTaskMethodBuilder<int>.Create();
    stateMachine.<>1__state = -1;
    stateMachine.<>t__builder.Start<<AlexsMethod>d__0>(ref stateMachine);
    return stateMachine.<>t__builder.Task;
}

There are two pieces of notation that are new to me. The first is <AlexsMethod>d__0. The second is stateMachine.<>4__this. Neither works when I try them myself, so I suspect it's for use by the compiler only. But I'm having trouble searching for more information on what is intended by this notation.

Answer 1

Unlike the brackets marking generics (e.g. Task<int>), they don't have special meaning. They're just what the compiler generates - identifiers that are valid in IL, but not in C#.

Answer 2

When you use lambda expression, lambda expression is a anonymous method. But compiler need to give it a name, so these methods are generated by compiler, it is not readable for human.