E07410: returning type must be same as the construct type

What went wrong

A constructor's return type doesn't match the enclosing class type. Constructors must return instances of their own class.

Worked examples

Compilable examples demonstrating this error and the correct fix:

• ek9 -q 864 (Why must the negate operator ~ return the same type as it...)
• ek9 -q 823 (Why must certain operators return specific types in EK9?)

How to fix it

1. Return type must match enclosing class name

Common causes

• Typo in return type
• Copy/paste error

See also

• E07410: constructor return type mismatch (this error)
• E07420: promotion operator same type

Examples

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

Fails with E07410: returning type must be same as the construct type

#!ek9
defines module error.e07410.bad

  defines class

    Toggle
      on <- false

      //'~' returns the type it is declared on, never another
      default operator ?

      operator ~ as pure
        <- rtn as Boolean: not on

Fixed: Return the type that declares the operator

#!ek9
defines module error.e07410.good

  defines class

    Toggle
      on as Boolean?

      default private Toggle() as pure

      Toggle() as pure
        -> initial as Boolean
        this.on :=? initial

      //'~' returns the type it is declared on
      default operator ?

      operator ~ as pure
        <- rtn as Toggle: Toggle(not on)

Questions and answers

These Q&A entries show E07410 and its fix:

• Q823: Why must certain operators return specific types in EK9?
• Q864: Why must the negate operator ~ return the same type as its class?