【Rust】型エイリアス(type)

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fn main(){
 
    let x = 123;
    println!("{}", type_of(x));
}
 
fn type_of<T>(_: T) -> &'static str {
    std::any::type_name::<T>()
}

c++だと、typeid

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#include <iostream>
#include <typeinfo>
 
struct Base {};
struct Derived : public Base {};
 
struct PolyBase {virtual void member(){}};
struct PolyDerived : public PolyBase {};
 
 
int main() {
    int i;
    int* pi;
    std::cout << "int is: " << typeid(int).name() << std::endl;
    std::cout << "i is: " << typeid(i).name() << std::endl;
    std::cout << "pi is: " << typeid(pi).name() << std::endl;
    std::cout << "*pi is: " << typeid(*pi).name() << std::endl;
    std::cout << std::endl;
 
    Derived derived;
    Base *pbase = &derived;
    std::cout << "derived is: " << typeid(derived).name() << std::endl;
    std::cout << "*pbase is: " << typeid(*pbase).name() << std::endl;
    std::cout << std::boolalpha << "same type? " << (typeid(derived) == typeid(*pbase)) << std::endl;
    std::cout << std::endl;
 
    PolyDerived polyderived;
    PolyBase* ppolybase = &polyderived;
    std::cout << "polyderived is: " << typeid(polyderived).name() << std::endl;
    std::cout << "*ppolybase is: " << typeid(*ppolybase).name() << std::endl;
    std::cout << std::boolalpha << "same type? " << (typeid(polyderived) == typeid(*ppolybase)) << std::endl;
}
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fn main(){
    let i = 10;
    let j = 3.14;
    println!("{}", type_of(i));
    println!("{}", type_of(j));
}
 
fn type_of<T>(_: T) -> &'static str {
    std::any::type_name::<T>()
}

derivedは派生。rustはclassがなくstructとimplなので、baseとderivedという概念があるか不明。。