rust: expected lifetime parameter problem [duplicate] - rust

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How to return new data from a function as a reference without borrow checker issues?
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I am new to Rust and was making a simple program to practice which takes 2 numbers and prints the numbers between them. This is my code
fn main() {
let a: u32 = 2;
let b: u32 = 10;
let a = result(&a, &b);
println!("{:?}", a);
}
fn result(a: &u32, b: &u32) -> [Vec<&u32>] {
let mut vec = Vec::new();
for x in a..b {
vec.push(a);
}
vec
}
When i run this program, i get this error
fn result(a: &u32, b: &u32) -> [Vec<&u32>] {
| ^ expected lifetime parameter
The concepts of borrowing and lifetimes are still very new and strange to me. Please help me in determining where i am wrong.

Answer 1

The error message is quite clear here:
this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from a or b
Providing an explicit lifetime would help the compiler understand what you're trying to do:
fn result<'a>(a: &'a u32, b: &'a u32) -> Vec<&'a u32> {
let mut vec: Vec<&'a u32> = Vec::new();
for x in *a..*b {
vec.push(&x);
}
vec
}
But the above wouldn't work either, as borrowing x results in borrowing a variable whch only lives in the scope a single iteration:
vec.push(&x);
^^ borrowed value does not live long enough
What you probably want is to avoid borrowing altogether:
fn result(a: u32, b: u32) -> Vec<u32> {
let mut vec = Vec::new();
for x in a..b {
vec.push(x);
}
vec
}
live example on godbolt.org