diff --git a/src/engine.rs b/src/engine.rs
index 7806382f..2ad03365 100644
--- a/src/engine.rs
+++ b/src/engine.rs
@@ -1105,7 +1105,7 @@ impl Engine {
                         .downcast_ref::<ImmutableString>()
                         .ok_or_else(|| EvalAltResult::ErrorStringIndexExpr(idx_pos))?;
 
-                    map.get_mut(index.as_str())
+                    map.get_mut(index)
                         .map(Target::from)
                         .unwrap_or_else(|| Target::from(()))
                 })
@@ -1208,10 +1208,8 @@ impl Engine {
             #[cfg(not(feature = "no_object"))]
             Dynamic(Union::Map(rhs_value)) => match lhs_value {
                 // Only allows String or char
-                Dynamic(Union::Str(s)) => Ok(rhs_value.contains_key(s.as_str()).into()),
-                Dynamic(Union::Char(c)) => {
-                    Ok(rhs_value.contains_key(c.to_string().as_str()).into())
-                }
+                Dynamic(Union::Str(s)) => Ok(rhs_value.contains_key(&s).into()),
+                Dynamic(Union::Char(c)) => Ok(rhs_value.contains_key(&c.to_string()).into()),
                 _ => Err(Box::new(EvalAltResult::ErrorInExpr(lhs.position()))),
             },
             Dynamic(Union::Str(rhs_value)) => match lhs_value {
diff --git a/src/fn_call.rs b/src/fn_call.rs
index 162410f3..861f490b 100644
--- a/src/fn_call.rs
+++ b/src/fn_call.rs
@@ -665,7 +665,8 @@ impl Engine {
                         ))
                     })
                     .and_then(|s| FnPtr::try_from(s))
-                    .map(Into::<Dynamic>::into);
+                    .map(Into::<Dynamic>::into)
+                    .map_err(|err| err.new_position(expr.position()));
             }
         }
 
diff --git a/src/packages/map_basic.rs b/src/packages/map_basic.rs
index cc1aa000..9437bc67 100644
--- a/src/packages/map_basic.rs
+++ b/src/packages/map_basic.rs
@@ -23,7 +23,7 @@ fn map_get_values(map: &mut Map) -> FuncReturn<Vec<Dynamic>> {
 def_package!(crate:BasicMapPackage:"Basic object map utilities.", lib, {
     lib.set_fn_2_mut(
         "has",
-        |map: &mut Map, prop: ImmutableString| Ok(map.contains_key(prop.as_str())),
+        |map: &mut Map, prop: ImmutableString| Ok(map.contains_key(&prop)),
     );
     lib.set_fn_1_mut("len", |map: &mut Map| Ok(map.len() as INT));
     lib.set_fn_1_mut("clear", |map: &mut Map| {
@@ -32,7 +32,7 @@ def_package!(crate:BasicMapPackage:"Basic object map utilities.", lib, {
     });
     lib.set_fn_2_mut(
         "remove",
-        |x: &mut Map, name: ImmutableString| Ok(x.remove(name.as_str()).unwrap_or_else(|| ().into())),
+        |x: &mut Map, name: ImmutableString| Ok(x.remove(&name).unwrap_or_else(|| ().into())),
     );
     lib.set_fn_2_mut(
         "mixin",
@@ -47,7 +47,7 @@ def_package!(crate:BasicMapPackage:"Basic object map utilities.", lib, {
         "fill_with",
         |map1: &mut Map, map2: Map| {
             map2.into_iter().for_each(|(key, value)| {
-                if !map1.contains_key(key.as_str()) {
+                if !map1.contains_key(&key) {
                     map1.insert(key, value);
                 }
             });
diff --git a/src/utils.rs b/src/utils.rs
index 13e11704..6668a7a9 100644
--- a/src/utils.rs
+++ b/src/utils.rs
@@ -6,6 +6,7 @@ use crate::stdlib::{
     any::TypeId,
     borrow::Borrow,
     boxed::Box,
+    cmp::Ordering,
     fmt,
     hash::{BuildHasher, Hash, Hasher},
     iter::FromIterator,
@@ -141,6 +142,12 @@ impl AsRef<String> for ImmutableString {
     }
 }
 
+impl Borrow<String> for ImmutableString {
+    fn borrow(&self) -> &String {
+        &self.0
+    }
+}
+
 impl Borrow<str> for ImmutableString {
     fn borrow(&self) -> &str {
         self.0.as_str()
@@ -348,6 +355,42 @@ impl AddAssign<char> for ImmutableString {
     }
 }
 
+impl<S: AsRef<str>> PartialEq<S> for ImmutableString {
+    fn eq(&self, other: &S) -> bool {
+        self.as_str().eq(other.as_ref())
+    }
+}
+
+impl PartialEq<ImmutableString> for str {
+    fn eq(&self, other: &ImmutableString) -> bool {
+        self.eq(other.as_str())
+    }
+}
+
+impl PartialEq<ImmutableString> for String {
+    fn eq(&self, other: &ImmutableString) -> bool {
+        self.eq(other.as_str())
+    }
+}
+
+impl<S: AsRef<str>> PartialOrd<S> for ImmutableString {
+    fn partial_cmp(&self, other: &S) -> Option<Ordering> {
+        self.as_str().partial_cmp(other.as_ref())
+    }
+}
+
+impl PartialOrd<ImmutableString> for str {
+    fn partial_cmp(&self, other: &ImmutableString) -> Option<Ordering> {
+        self.partial_cmp(other.as_str())
+    }
+}
+
+impl PartialOrd<ImmutableString> for String {
+    fn partial_cmp(&self, other: &ImmutableString) -> Option<Ordering> {
+        self.as_str().partial_cmp(other.as_str())
+    }
+}
+
 impl ImmutableString {
     /// Consume the `ImmutableString` and convert it into a `String`.
     /// If there are other references to the same string, a cloned copy is returned.