Touch up PR 180

src/de.rs

@@ -556,11 +556,11 @@ where
             return visitor.visit_i64(n);
         }
     }
-    // After handling the different number encodings above
-    // if we are left with leading zero(s) followed by numeric characters
-    // this is in fact a string according to the YAML 1.2 spec
-    // https://yaml.org/spec/1.2/spec.html#id2761292
-    if v.len() > 1 &&  v.starts_with('0') && v.chars().all(char::is_numeric) {
+    if v.len() > 1 && v.starts_with('0') && v.bytes().all(|b| b.is_ascii_digit()) {
+        // After handling the different number encodings above if we are left
+        // with leading zero(s) followed by numeric characters this is in fact a
+        // string according to the YAML 1.2 spec.
+        // https://yaml.org/spec/1.2/spec.html#id2761292
         return visitor.visit_str(v);
     }
     if let Ok(n) = v.parse() {

tests/test_value.rs

@@ -10,11 +10,14 @@ fn test_nan() {
     let neg_fake_nan = serde_yaml::from_str::<Value>("-.nan").unwrap();
     assert!(neg_fake_nan.is_string());
 
-    let num_string = serde_yaml::from_str::<Value>("01").unwrap();
-    assert!(num_string.is_string());
-
     let significand_mask = 0xF_FFFF_FFFF_FFFF;
     let bits = (f64::NAN.to_bits() ^ significand_mask) | 1;
     let different_pos_nan = Value::Number(Number::from(f64::from_bits(bits)));
     assert_eq!(pos_nan, different_pos_nan);
 }
+
+#[test]
+fn test_digits() {
+    let num_string = serde_yaml::from_str::<Value>("01").unwrap();
+    assert!(num_string.is_string());
+}