Вы можете найти его в документации :
//create a TypeAlias and store it to use the name later
val typeAlias = TypeAliasSpec.builder("MyAlias", BigDecimal::class).build()
val type = TypeSpec.classBuilder("TemplateState").primaryConstructor(
FunSpec.constructorBuilder().addParameter(
//You can use the ClassName class to get the typeAlias type
ParameterSpec.builder("test", ClassName("", typeAlias.name)).build()
)
).build()
FileSpec.builder("com.example", "HelloWorld")
.addTypeAlias(typeAlias)
.addType(type)
.build()