alias vs enum for lambdas?

[Orion]

In which programming scenarios should alias be used instead of 
enum?

So far I have only found a simplified notation of a generic 
lambda:
alias id = (x) => x; x; , which does not work in the case of enum.

There is also a difference in overloading a non-generic lambda:

alias m = (int x) => x;
alias m = (float x) => 0.5 + x;
- alias overloads a function with the same name.

enum e = (int x) => x;
///enum e = (float x) => x; //error
- enum does not.

At the compiler level, enum lambda is represented as a literal.
But how is alias represented? As an expression?