Rust: Add a few more test cases for constants / constant propagation.

Author: geoffw0

rust/ql/test/query-tests/security/CWE-798/test_heuristic.rs

@@ -68,6 +68,9 @@ fn test(var_string: &str, var_data: &[u8;16], var_u64: u64) {
     mc2.set_salt_u64(var_u64);
     mc2.set_salt_u64(var_u64 + 1);
     mc2.set_salt_u64((var_u64 << 32) ^ (var_u64  & 0xFFFFFFFF));
+    mc2.set_salt_u64(1 << 4); // $ MISSING: Alert[rust/hard-coded-cryptographic-value]
+    mc2.set_salt_u64(u64::MAX); // $ MISSING: Alert[rust/hard-coded-cryptographic-value]
+    mc2.set_salt_u64(u64::MAX / 4); // $ MISSING: Alert[rust/hard-coded-cryptographic-value]
 
     let mut key1 = "foo".to_string(); // $ MISSING: Alert[rust/hard-coded-cryptographic-value]
     key1 += "bar"; // $ MISSING: Alert[rust/hard-coded-cryptographic-value]
@@ -76,4 +79,8 @@ fn test(var_string: &str, var_data: &[u8;16], var_u64: u64) {
     let mut key2 = "foo".to_string();
     key2 += var_string;
     let _ = MyCryptor::new(&key2);
+
+    let mut key3 = var_string.to_string();
+    key3 += "bar";
+    let _ = MyCryptor::new(&key3);
 }