Why is it possible to declare variable with same name in the REPL?

Question

scala> val hi = \"Hello \\\"e\"
hi: String = Hello \"e


scala> val hi = \"go\"
hi: String = go

Within same REPL session why its allowing me

Answer 1

In the first piece of code I believe this is a "feature" of the REPL allowing your to redefine hi. Suppose you are working through building a small piece of code in the REPL then it might be helpful to go back and change a prior definition without rewriting the others to use a different value.

The following code would give an error error: x is already defined as value x when compiling with scalac.

class Foo{
  val x = "foo"
  val x = "foo"
}

In the second piece of code you are trying to reassign a val which cannot be changed. This is what you would expect.