FunctionDefinition {
  specifiers {
    TypeReference {
      kind: TypeReferenceKind.BUILTIN (3)
      name: 'void'
      decl  { }
    }
  }
  decl {
    ParenDeclarator {
      decl {
        IdentifierDeclarator {
          name: 'main'
        }
      }
      parameter_types  { }
      identifiers  { }
    }
  }
  old_style_declarations  { }
  body  { }
}