E02080: use of a delegate and methods of same name

What went wrong

A function delegate field has the same name as a method in the class. This creates ambiguity: does 'name()' call the method or invoke the delegate?

Worked examples

Compilable examples demonstrating this error and the correct fix:

• ek9 -q 57 (How can I change method behaviour on a class without subc...)

How to fix it

• Rename the delegate field (add 'Delegate' suffix)
• Or rename the method to be distinct

Rationale

When you write 'obj.processor("input")', EK9 cannot determine:

• Should it call the method 'processor()'?
• Should it invoke the delegate stored in 'processor' field?

Common causes

• Using same naming convention for delegates and methods
• Refactoring that introduced a naming collision

See also

• E02030: duplicate/ambiguous methods
• E06140: ambiguous match

Examples

Every example is compiled by the EK9 compiler: the first fails exactly as captioned, the others fix it.

Fails with E02080: use of a delegate and methods of same name

#!ek9
defines module error.e02080.bad

  defines class

    Counter

      current()
        <- rtn as Integer?

        //A delegate named like the method below: which one does next() call?
        next <- () is NumberSource as function (rtn: 22)
        rtn: next()

      next()
        <- rtn as Integer: 1

  defines function

    NumberSource() as abstract
      <- rtn as Integer?

Fixed: Give the delegate a name no method has, such as one ending in Source or Handler

#!ek9
defines module error.e02080.good

  defines class

    Counter

      current()
        <- rtn as Integer?
        nextSource <- () is NumberSource as function (rtn: 22)
        rtn: nextSource() + next()

      next()
        <- rtn as Integer: 1

  defines function

    NumberSource() as abstract
      <- rtn as Integer?

Questions and answers

These Q&A entries show E02080 and its fix:

• Q57: How can I change method behaviour on a class without subclassing?