str-slice start/end equality does not preclude output

src/builtin/string.rs

@@ -111,7 +111,7 @@ pub(crate) fn register(f: &mut HashMap<String, Builtin>) {
                 end = str_len;
             }
 
-            if start >= end || start > str_len {
+            if start > end || start > str_len {
                 Ok(Value::Ident(String::new(), quotes.normalize()))
             } else {
                 let s = string[start - 1..end].to_string();

tests/strings.rs

@@ -93,6 +93,11 @@ test!(
     "a {\n  color: str-slice($string: \"foo\", $start-at: 99999999999999999999, $end-at: -99999999999999999999);\n}\n",
     "a {\n  color: \"\";\n}\n"
 );
+test!(
+    str_slice_start_end_equal,
+    "a {\n  color: str-slice(\"cde\", 1, 1);\n}\n",
+    "a {\n  color: \"c\";\n}\n"
+);
 test!(
     str_len_dbl_quotes,
     "a {\n  color: str-length(\"cde\");\n}\n",