operator == method Null safety

Test whether another object is equal to this function.

Function objects are only equal to other function objects (an object satisfying object is Function), and never to non-function objects.

Some function objects are considered equal by == because they are recognized as representing the "same function":

• It is the same object. Static and top-level functions are compile time constants when used as values, so referring to the same function twice always give the same object, as does referring to a local function declaration twice in the same scope where it was declared.
• if they refer to the same member method extracted from the same object. Repeatedly extracting an instance method of an object as a function value gives equal, but not necessarily identical, function values.

Different evaluations of function literals never give rise to equal function objects. Each time a function literal is evaluated, it creates a new function value that is not equal to any other function value, not even ones created by the same expression.