Higher-order functions in 3 different languages

main.dart

int one() => 1;
T Function() passThrough1<T>(T Function() fun) => () => fun();
T Function(T Function() fun) passThrough2<T>() => (fun) => fun();

void main() async {
  final result1 = passThrough1(one)(); // Can infer the type
  final result2 = passThrough2()(one); // Can't infer the type ;(
}

main.kt

fun one(): Int = 1;
fun <T> passThrough1(func: () -> T) = { func() };
fun <T> passThrough2(): (func: () -> T) -> T = { it() };

fun main() {
    val result1 = passThrough1(::one)() // Can infer the type
    val result2 = passThrough2()(::one) // Can't infer the type ;( also compiler error
}

main.ts

const one = () => 1;
const passThrough1 = <T extends any>(fun: () => T) => () => fun(); 
const passThrough2 = <T extends any>() => (fun: () => T) => fun(); 

const result1 = passThrough1(one)(); // Can infer the type
const result2 = passThrough2()(one); // Can't infer the type ;(