got it to compile

rust/insert_digit_anywhere_primes_ev/Cargo.toml

@@ -2,10 +2,10 @@
 name = "insert_digit_anywhere_primes_constant"
 version = "0.1.0"
 authors = ["William Ball <wball1@swarthmore.edu>"]
-edition = "2018"
+edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-is_prime = "1.0.5"
-rand = "0.7.3"
+is_prime = "2.0.7"
+rand = "*"

rust/insert_digit_anywhere_primes_ev/src/main.rs

@@ -1,4 +1,4 @@
-use is_prime::is_prime_with_witnesses;
+use is_prime::is_prime;
 use rand::prelude::*;
 use std::io::prelude::*;
 
@@ -14,7 +14,7 @@ fn step(x: String, rng: &mut ThreadRng) -> Option<String> {
         let mut copy = x.clone();
         copy.insert(i, (d + '0' as u8) as char);
         if copy.as_bytes()[0] != '0' as u8 {
-            if is_prime_with_witnesses(&copy, 40) {
+            if is_prime(&copy) {
                 return Some(copy);
             }
         }