Rust not finding environment variable defined in .zshrc

envtest.rs

use std::env;

fn main() {
    let var = env::var("SOME_VAR");
    println!("SOME_VAR: {var:?}");
}

// When SOME_VAR is define in .zshrc:
/*
~/Developer/envtest
❯ echo $SOME_VAR
Hello World

~/Developer/envtest
❯ cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s
     Running `target/debug/envtest`
SOME_VAR: Err(NotPresent)
*/

// When SOME_VAR is defined in the shell environment directly:
/*
~/Developer/envtest
❯ export SOME_VAR="Good Evening"

~/Developer/envtest
❯ cargo run
   Compiling envtest v0.1.0 (/Users/dehanjl/Developer/envtest)
    Finished dev [unoptimized + debuginfo] target(s) in 0.30s
     Running `target/debug/envtest`
SOME_VAR: Ok("Good Evening")
*/