merge from main

crates/nu-command/tests/commands/mut_.rs

@@ -148,3 +148,14 @@ fn def_should_not_mutate_mut() {
     assert!(actual.err.contains("capture of mutable variable"));
     assert!(!actual.status.success())
 }
+
+#[test]
+fn mut_with_bad_syntax_raises_parse_error() {
+    let actual = nu!("let x = 3; $x = 4");
+    assert!(actual
+        .err
+        .contains("parser::assignment_requires_mutable_variable"));
+
+    let actual = nu!("mut x = 3; x = 5");
+    assert!(actual.err.contains("parser::assignment_requires_variable"));
+}