diff --git a/src/api/custom_syntax.rs b/src/api/custom_syntax.rs
index 7ee568c0..868b9931 100644
--- a/src/api/custom_syntax.rs
+++ b/src/api/custom_syntax.rs
@@ -10,9 +10,9 @@ use crate::{
     reify, Dynamic, Engine, EvalContext, Identifier, ImmutableString, LexError, Position,
     RhaiResult, StaticVec,
 };
-use std::ops::Deref;
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
+use std::{borrow::Borrow, ops::Deref};
 
 /// Collection of special markers for custom syntax definition.
 pub mod markers {
@@ -145,6 +145,14 @@ impl Expression<'_> {
     }
 }
 
+impl Borrow<Expr> for Expression<'_> {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &Expr {
+        self.0
+    }
+}
+
 impl AsRef<Expr> for Expression<'_> {
     #[inline(always)]
     #[must_use]
diff --git a/src/ast/ast.rs b/src/ast/ast.rs
index d0b88e26..98ed86b3 100644
--- a/src/ast/ast.rs
+++ b/src/ast/ast.rs
@@ -5,6 +5,7 @@ use crate::{Dynamic, FnNamespace, Identifier, Position};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
+    borrow::Borrow,
     fmt,
     hash::Hash,
     ops::{Add, AddAssign},
@@ -919,6 +920,14 @@ impl<A: Into<Self>> AddAssign<A> for AST {
     }
 }
 
+impl Borrow<[Stmt]> for AST {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &[Stmt] {
+        self.statements()
+    }
+}
+
 impl AsRef<[Stmt]> for AST {
     #[inline(always)]
     #[must_use]
@@ -927,6 +936,15 @@ impl AsRef<[Stmt]> for AST {
     }
 }
 
+#[cfg(not(feature = "no_function"))]
+impl Borrow<crate::Module> for AST {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &crate::Module {
+        &self.shared_lib()
+    }
+}
+
 #[cfg(not(feature = "no_function"))]
 impl AsRef<crate::Module> for AST {
     #[inline(always)]
@@ -936,6 +954,15 @@ impl AsRef<crate::Module> for AST {
     }
 }
 
+#[cfg(not(feature = "no_function"))]
+impl Borrow<crate::Shared<crate::Module>> for AST {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &crate::Shared<crate::Module> {
+        self.shared_lib()
+    }
+}
+
 #[cfg(not(feature = "no_function"))]
 impl AsRef<crate::Shared<crate::Module>> for AST {
     #[inline(always)]
diff --git a/src/ast/ident.rs b/src/ast/ident.rs
index e8eb6626..ffc5f968 100644
--- a/src/ast/ident.rs
+++ b/src/ast/ident.rs
@@ -4,6 +4,7 @@ use crate::{ImmutableString, Position};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
+    borrow::Borrow,
     fmt,
     hash::Hash,
     ops::{Deref, DerefMut},
@@ -28,6 +29,14 @@ impl fmt::Debug for Ident {
     }
 }
 
+impl Borrow<str> for Ident {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &str {
+        self.name.as_ref()
+    }
+}
+
 impl AsRef<str> for Ident {
     #[inline(always)]
     #[must_use]
diff --git a/src/ast/stmt.rs b/src/ast/stmt.rs
index a72e2f01..6b15061c 100644
--- a/src/ast/stmt.rs
+++ b/src/ast/stmt.rs
@@ -7,6 +7,7 @@ use crate::{calc_fn_hash, Position, StaticVec, INT};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
 use std::{
+    borrow::Borrow,
     collections::BTreeMap,
     fmt,
     hash::Hash,
@@ -443,6 +444,14 @@ impl DerefMut for StmtBlock {
     }
 }
 
+impl Borrow<[Stmt]> for StmtBlock {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &[Stmt] {
+        &self.block
+    }
+}
+
 impl AsRef<[Stmt]> for StmtBlock {
     #[inline(always)]
     #[must_use]
diff --git a/src/eval/expr.rs b/src/eval/expr.rs
index 285f5e23..c8d17896 100644
--- a/src/eval/expr.rs
+++ b/src/eval/expr.rs
@@ -251,7 +251,7 @@ impl Engine {
                 get_builtin_binary_op_fn(operator_token.as_ref().unwrap(), operands[0], operands[1])
             {
                 // Built-in found
-                let context = (self, name, None, &*global, lib, pos, level + 1).into();
+                let context = (self, name.as_str(), None, &*global, lib, pos, level + 1).into();
                 return func(context, operands);
             }
 
diff --git a/src/eval/target.rs b/src/eval/target.rs
index 5a441520..c48aa62a 100644
--- a/src/eval/target.rs
+++ b/src/eval/target.rs
@@ -2,9 +2,12 @@
 
 use crate::types::dynamic::Variant;
 use crate::{Dynamic, Position, RhaiResultOf};
-use std::ops::{Deref, DerefMut};
 #[cfg(feature = "no_std")]
 use std::prelude::v1::*;
+use std::{
+    borrow::Borrow,
+    ops::{Deref, DerefMut},
+};
 
 // Calculate an offset+len pair given an actual length of the underlying array.
 //
@@ -422,6 +425,14 @@ impl AsRef<Dynamic> for Target<'_> {
     }
 }
 
+impl Borrow<Dynamic> for Target<'_> {
+    #[inline(always)]
+    #[must_use]
+    fn borrow(&self) -> &Dynamic {
+        self
+    }
+}
+
 impl DerefMut for Target<'_> {
     #[inline]
     fn deref_mut(&mut self) -> &mut Dynamic {
diff --git a/src/func/native.rs b/src/func/native.rs
index b3681e74..707f8f4c 100644
--- a/src/func/native.rs
+++ b/src/func/native.rs
@@ -81,13 +81,13 @@ pub struct NativeCallContext<'a> {
     level: usize,
 }
 
-impl<'a, M: AsRef<[&'a Module]> + ?Sized, S: AsRef<str> + 'a + ?Sized>
+impl<'a>
     From<(
         &'a Engine,
-        &'a S,
-        Option<&'a S>,
+        &'a str,
+        Option<&'a str>,
         &'a GlobalRuntimeState<'a>,
-        &'a M,
+        &'a [&Module],
         Position,
         usize,
     )> for NativeCallContext<'a>
@@ -96,37 +96,35 @@ impl<'a, M: AsRef<[&'a Module]> + ?Sized, S: AsRef<str> + 'a + ?Sized>
     fn from(
         value: (
             &'a Engine,
-            &'a S,
-            Option<&'a S>,
+            &'a str,
+            Option<&'a str>,
             &'a GlobalRuntimeState,
-            &'a M,
+            &'a [&Module],
             Position,
             usize,
         ),
     ) -> Self {
         Self {
             engine: value.0,
-            fn_name: value.1.as_ref(),
-            source: value.2.map(<_>::as_ref),
+            fn_name: value.1,
+            source: value.2,
             global: Some(value.3),
-            lib: value.4.as_ref(),
+            lib: value.4,
             pos: value.5,
             level: value.6,
         }
     }
 }
 
-impl<'a, M: AsRef<[&'a Module]> + ?Sized, S: AsRef<str> + 'a + ?Sized>
-    From<(&'a Engine, &'a S, &'a M)> for NativeCallContext<'a>
-{
+impl<'a> From<(&'a Engine, &'a str, &'a [&'a Module])> for NativeCallContext<'a> {
     #[inline(always)]
-    fn from(value: (&'a Engine, &'a S, &'a M)) -> Self {
+    fn from(value: (&'a Engine, &'a str, &'a [&Module])) -> Self {
         Self {
             engine: value.0,
-            fn_name: value.1.as_ref(),
+            fn_name: value.1,
             source: None,
             global: None,
-            lib: value.2.as_ref(),
+            lib: value.2,
             pos: Position::NONE,
             level: 0,
         }
@@ -142,14 +140,10 @@ impl<'a> NativeCallContext<'a> {
     )]
     #[inline(always)]
     #[must_use]
-    pub fn new(
-        engine: &'a Engine,
-        fn_name: &'a (impl AsRef<str> + 'a + ?Sized),
-        lib: &'a [&Module],
-    ) -> Self {
+    pub fn new(engine: &'a Engine, fn_name: &'a str, lib: &'a [&Module]) -> Self {
         Self {
             engine,
-            fn_name: fn_name.as_ref(),
+            fn_name,
             source: None,
             global: None,
             lib,
@@ -167,8 +161,8 @@ impl<'a> NativeCallContext<'a> {
     #[must_use]
     pub fn new_with_all_fields(
         engine: &'a Engine,
-        fn_name: &'a (impl AsRef<str> + 'a + ?Sized),
-        source: Option<&'a (impl AsRef<str> + 'a + ?Sized)>,
+        fn_name: &'a str,
+        source: Option<&'a str>,
         global: &'a GlobalRuntimeState,
         lib: &'a [&Module],
         pos: Position,
@@ -176,8 +170,8 @@ impl<'a> NativeCallContext<'a> {
     ) -> Self {
         Self {
             engine,
-            fn_name: fn_name.as_ref(),
-            source: source.map(<_>::as_ref),
+            fn_name,
+            source,
             global: Some(global),
             lib,
             pos,
diff --git a/src/optimizer.rs b/src/optimizer.rs
index 20145659..42e9dd90 100644
--- a/src/optimizer.rs
+++ b/src/optimizer.rs
@@ -1191,7 +1191,7 @@ fn optimize_expr(expr: &mut Expr, state: &mut OptimizerState, _chaining: bool) {
                             #[cfg(feature = "no_function")]
                             let lib = &[];
 
-                            let context = (state.engine, &x.name, lib).into();
+                            let context = (state.engine, x.name.as_str(), lib).into();
                             let (first, second) = arg_values.split_first_mut().unwrap();
                             (f)(context, &mut [ first, &mut second[0] ]).ok()
                         }) {