diff --git a/crates/nu-engine/src/evaluate/operator.rs b/crates/nu-engine/src/evaluate/operator.rs
index 4cea18f20f..c6318382d0 100644
--- a/crates/nu-engine/src/evaluate/operator.rs
+++ b/crates/nu-engine/src/evaluate/operator.rs
@@ -55,8 +55,8 @@ pub fn apply_operator(
             )),
             _ => res,
         }),
-        Operator::In => table_contains(left, right).map(UntaggedValue::boolean),
-        Operator::NotIn => table_contains(left, right).map(|x| UntaggedValue::boolean(!x)),
+        Operator::In => inside_of(left, right).map(UntaggedValue::boolean),
+        Operator::NotIn => inside_of(left, right).map(|x| UntaggedValue::boolean(!x)),
         Operator::And => match (left.as_bool(), right.as_bool()) {
             (Ok(left), Ok(right)) => Ok(UntaggedValue::boolean(left && right)),
             _ => Err((left.type_name(), right.type_name())),
@@ -89,12 +89,12 @@ fn string_contains(
     }
 }
 
-fn table_contains(
+fn inside_of(
     left: &UntaggedValue,
     right: &UntaggedValue,
 ) -> Result<bool, (&'static str, &'static str)> {
-    match right {
-        UntaggedValue::Table(values) => {
+    match (left, right) {
+        (_, UntaggedValue::Table(values)) => {
             Ok(values
                 .iter()
                 .any(|x| match compare_values(Operator::Equal, left, &x.value) {
@@ -102,6 +102,10 @@ fn table_contains(
                     _ => false,
                 }))
         }
+        (
+            UntaggedValue::Primitive(Primitive::String(lhs)),
+            UntaggedValue::Primitive(Primitive::String(rhs)),
+        ) => Ok(rhs.contains(lhs)),
         _ => Err((left.type_name(), right.type_name())),
     }
 }
diff --git a/crates/nu-protocol/src/return_value.rs b/crates/nu-protocol/src/return_value.rs
index 01a89a431b..f097c60443 100644
--- a/crates/nu-protocol/src/return_value.rs
+++ b/crates/nu-protocol/src/return_value.rs
@@ -130,7 +130,8 @@ mod tests {
 
     #[test]
     fn return_value_can_be_used_in_assert_eq() {
-        let v: ReturnValue = ReturnSuccess::value(UntaggedValue::nothing());
-        assert_eq!(v, v);
+        let v1: ReturnValue = ReturnSuccess::value(UntaggedValue::nothing());
+        let v2: ReturnValue = ReturnSuccess::value(UntaggedValue::nothing());
+        assert_eq!(v1, v2);
     }
 }
diff --git a/tests/shell/pipeline/commands/internal.rs b/tests/shell/pipeline/commands/internal.rs
index 789b5d9e79..108421b5d7 100644
--- a/tests/shell/pipeline/commands/internal.rs
+++ b/tests/shell/pipeline/commands/internal.rs
@@ -679,6 +679,31 @@ fn negative_decimal_start() {
 
     assert_eq!(actual.out, "2.7");
 }
+
+#[test]
+fn string_inside_of() {
+    let actual = nu!(
+        cwd: ".",
+        r#"
+            "bob" in "bobby"
+        "#
+    );
+
+    assert_eq!(actual.out, "true");
+}
+
+#[test]
+fn string_not_inside_of() {
+    let actual = nu!(
+        cwd: ".",
+        r#"
+            "bob" not-in "bobby"
+        "#
+    );
+
+    assert_eq!(actual.out, "false");
+}
+
 #[test]
 fn index_row() {
     let actual = nu!(