Question

In F# what is the difference between an internal method and a private method.

I have a feeling that they are implemented the same, but mean something different.

Answer 1

An internal method can be accessed from any type (or function) in the same .NET assembly.
A private method can be accessed only from the type where it was declared.

Here is a simple snippet that shows the difference:

type A() = 
  member internal x.Foo = 1

type B() = 
  member private x.Foo = 1

let a = A()
let b = B()
a.Foo // Works fine (we're in the same project)
b.Foo // Error FS0491: 'Foo' is not defined