diff --git a/RELEASES.md b/RELEASES.md
index 8ba7d09c..22aae65d 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -18,6 +18,7 @@ New features
 * Anonymous functions in the syntax of a closure, e.g. `|x, y, z| x + y - z`.
 * Custom syntax now works even without the `internals` feature.
 * Currying of function pointers is supported via the `curry` keyword.
+* `Module::set_indexer_get_set_fn` is added as a shorthand of both `Module::set_indexer_get_fn` and `Module::set_indexer_set_fn`.
 
 Breaking changes
 ----------------
diff --git a/src/engine.rs b/src/engine.rs
index cb7234d3..f34cb7ca 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -11,7 +11,7 @@ use crate::parser::{Expr, FnAccess, ImmutableString, ReturnType, ScriptFnDef, St
 use crate::r#unsafe::unsafe_cast_var_name_to_lifetime;
 use crate::result::EvalAltResult;
 use crate::scope::{EntryType as ScopeEntryType, Scope};
-use crate::syntax::{CustomSyntax, EvalContext, Expression};
+use crate::syntax::{CustomSyntax, EvalContext};
 use crate::token::Position;
 use crate::utils::StaticVec;
 
@@ -1020,7 +1020,7 @@ impl Engine {
                     map.entry(index).or_insert(Default::default()).into()
                 } else {
                     let index = idx
-                        .downcast_ref::<String>()
+                        .downcast_ref::<ImmutableString>()
                         .ok_or_else(|| EvalAltResult::ErrorStringIndexExpr(idx_pos))?;
 
                     map.get_mut(index.as_str())
diff --git a/src/module.rs b/src/module.rs
index 7216c248..11787e1c 100644
--- a/src/module.rs
+++ b/src/module.rs
@@ -738,18 +738,18 @@ impl Module {
     /// });
     /// assert!(module.contains_fn(hash));
     /// ```
-    pub fn set_indexer_set_fn<A: Variant + Clone, B: Variant + Clone>(
+    pub fn set_indexer_set_fn<A: Variant + Clone, B: Variant + Clone, C: Variant + Clone>(
         &mut self,
-        func: impl Fn(&mut A, B, A) -> FuncReturn<()> + SendSync + 'static,
+        func: impl Fn(&mut A, B, C) -> FuncReturn<()> + SendSync + 'static,
     ) -> u64 {
         let f = move |_: &Engine, _: &Module, args: &mut FnCallArgs| {
             let b = mem::take(args[1]).cast::<B>();
-            let c = mem::take(args[2]).cast::<A>();
+            let c = mem::take(args[2]).cast::<C>();
             let a = args[0].downcast_mut::<A>().unwrap();
 
             func(a, b, c).map(Dynamic::from)
         };
-        let arg_types = [TypeId::of::<A>(), TypeId::of::<B>(), TypeId::of::<A>()];
+        let arg_types = [TypeId::of::<A>(), TypeId::of::<B>(), TypeId::of::<C>()];
         self.set_fn(
             FN_IDX_SET,
             Public,
@@ -758,6 +758,40 @@ impl Module {
         )
     }
 
+    /// Set a pair of Rust index getter and setter functions, returning both hash keys.
+    /// This is a shorthand for `set_indexer_get_fn` and `set_indexer_set_fn`.
+    ///
+    /// If there are similar existing Rust functions, they are replaced.
+    ///
+    /// # Examples
+    ///
+    /// ```
+    /// use rhai::{Module, ImmutableString};
+    ///
+    /// let mut module = Module::new();
+    /// let (hash_get, hash_set) = module.set_indexer_get_set_fn(
+    ///     |x: &mut i64, y: ImmutableString| {
+    ///         Ok(*x + y.len() as i64)
+    ///     },
+    ///     |x: &mut i64, y: ImmutableString, value: i64| {
+    ///         *x = y.len() as i64 + value;
+    ///         Ok(())
+    ///     }
+    /// );
+    /// assert!(module.contains_fn(hash_get));
+    /// assert!(module.contains_fn(hash_set));
+    /// ```
+    pub fn set_indexer_get_set_fn<A: Variant + Clone, B: Variant + Clone, T: Variant + Clone>(
+        &mut self,
+        getter: impl Fn(&mut A, B) -> FuncReturn<T> + SendSync + 'static,
+        setter: impl Fn(&mut A, B, T) -> FuncReturn<()> + SendSync + 'static,
+    ) -> (u64, u64) {
+        (
+            self.set_indexer_get_fn(getter),
+            self.set_indexer_set_fn(setter),
+        )
+    }
+
     /// Set a Rust function taking four parameters into the module, returning a hash key.
     ///
     /// If there is a similar existing Rust function, it is replaced.
diff --git a/tests/functions.rs b/tests/functions.rs
index 3c0a080b..78d20fa3 100644
--- a/tests/functions.rs
+++ b/tests/functions.rs
@@ -104,5 +104,19 @@ fn test_function_pointers() -> Result<(), Box<EvalAltResult>> {
         42
     );
 
+    #[cfg(not(feature = "no_object"))]
+    assert_eq!(
+        engine.eval::<INT>(
+            r#"
+                fn foo(x) { this.data += x; }
+
+                let x = #{ data: 40, action: Fn("foo") };
+                x.action(2);
+                x.data
+            "#
+        )?,
+        42
+    );
+
     Ok(())
 }