diff --git a/Cargo.toml b/Cargo.toml
index 54331e51..80ab0cf2 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,7 @@ rhai_codegen = { version = "1.4.1", path = "codegen", default-features = false }
 
 no-std-compat = { version = "0.4", default-features = false, features = ["alloc"], optional = true }
 libm = { version = "0.2", default-features = false, optional = true }
+hashbrown = { version = "0.12", optional = true }
 core-error = { version = "0.0", default-features = false, features = ["alloc"], optional = true }
 serde = { version = "1.0", default-features = false, features = ["derive", "alloc"], optional = true }
 serde_json = { version = "1.0", default-features = false, features = ["alloc"], optional = true }
@@ -63,7 +64,7 @@ debugging = ["internals"]       # enable debugging
 serde = ["dep:serde", "smartstring/serde", "smallvec/serde"] # implement serde for rhai types
 
 # compiling for no-std
-no_std = ["no-std-compat", "num-traits/libm", "core-error", "libm", "ahash/compile-time-rng"]
+no_std = ["no-std-compat", "num-traits/libm", "core-error", "libm", "ahash/compile-time-rng", "hashbrown"]
 
 # compiling for WASM
 wasm-bindgen = ["instant/wasm-bindgen"]
diff --git a/src/eval/expr.rs b/src/eval/expr.rs
index 22f22567..a0411410 100644
--- a/src/eval/expr.rs
+++ b/src/eval/expr.rs
@@ -10,6 +10,9 @@ use crate::func::{
 };
 use crate::types::dynamic::AccessMode;
 use crate::{Dynamic, Engine, Module, Position, RhaiResult, RhaiResultOf, Scope, ERR};
+#[cfg(feature = "no_std")]
+use hashbrown::hash_map::Entry;
+#[cfg(not(feature = "no_std"))]
 use std::collections::hash_map::Entry;
 use std::num::NonZeroUsize;
 #[cfg(feature = "no_std")]
diff --git a/src/func/hashing.rs b/src/func/hashing.rs
index ebcc96a6..75331f66 100644
--- a/src/func/hashing.rs
+++ b/src/func/hashing.rs
@@ -4,12 +4,18 @@
 use std::prelude::v1::*;
 use std::{
     any::TypeId,
-    collections::{HashMap, HashSet},
     hash::{BuildHasher, Hash, Hasher},
 };
 
-pub type StraightHashMap<K, V> = HashMap<K, V, StraightHasherBuilder>;
-pub type StraightHashSet<K> = HashSet<K, StraightHasherBuilder>;
+#[cfg(feature = "no_std")]
+pub type StraightHashMap<K, V> = hashbrown::HashMap<K, V, StraightHasherBuilder>;
+#[cfg(feature = "no_std")]
+pub type StraightHashSet<K> = hashbrown::HashSet<K, StraightHasherBuilder>;
+
+#[cfg(not(feature = "no_std"))]
+pub type StraightHashMap<K, V> = std::collections::HashMap<K, V, StraightHasherBuilder>;
+#[cfg(not(feature = "no_std"))]
+pub type StraightHashSet<K> = std::collections::HashSet<K, StraightHasherBuilder>;
 
 /// Dummy hash value to map zeros to. This value can be anything.
 ///
@@ -47,7 +53,11 @@ impl Hasher for StraightHasher {
     }
 
     fn write_u64(&mut self, i: u64) {
-        self.0 = i;
+        if i == 0 {
+            self.0 = ALT_ZERO_HASH;
+        } else {
+            self.0 = i;
+        }
     }
 }