E04070: as it is not 'template/generic' in nature

What went wrong

You're providing type parameters (e.g., 'of String') to a type that isn't generic/parameterized. Only generic types accept type parameters. Non-generic types have fixed structure and don't need/accept 'of' clauses.

Worked examples

Compilable examples demonstrating this error and the correct fix:

• ek9 -q 1309 (Why does EK9 reject 'of TypeName' on a non-generic typ...)

[GENERIC VS NON-GENERIC] Generic types (accept 'of' clause):

• List of T, Dict of (K, V), Optional of T, Result of (T, E)
• User-defined: 'Container of type T' syntax

Non-generic types (NO 'of' clause):

• String, Integer, Float, Boolean, Character
• Custom classes without 'of type T' declaration

How to fix it

1. Check if the type is generic (look for 'of type T' in its definition)
2. If non-generic, remove the 'of TypeName' clause
3. If you need generic behavior, create a generic class or use built-in generic

Common causes

• Confusing class name with generic type
• Copy-pasting from generic code to non-generic context
• Assuming all collection-like classes are generic

See also

• E04070: using 'of' on NON-generic type (this error)
• E04080: MISSING 'of' on generic type (opposite problem)
• E06020: wrong NUMBER of type parameters on generic

Examples

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

Fails with E04070: as it is not 'template/generic' in nature

#!ek9
defines module error.e04070.bad

  defines function

    aNonGenericFunction()
      -> text as String
      <- rtn as String: text

    badClassUseOfNonGeneric()
      //Failure 1
      notActuallyGeneric <- Date() of String

      //Failure 2
      alsoNotGeneric as Date of String?

    badFunctionUseOfNonGeneric()
      //Failure 3
      handler <- () is aNonGenericFunction of Date as function

      //Failure 4
      functionName as aNonGenericFunction of String?

Fixed: Only a generic type or function takes 'of': use Date and the function as they are

#!ek9
defines module error.e04070.good

  defines function

    aNonGenericFunction()
      -> text as String
      <- rtn as String: text

    classUse()
      today <- Date()
      names <- List() of String
      require today? and names?

    functionUse()
      <- rtn as String: aNonGenericFunction("plain")

Questions and answers

These Q&A entries show E04070 and its fix:

• Q1309: Why does EK9 reject 'of TypeName' on a non-generic type like String?