diff --git a/crates/lib/Cargo.toml b/crates/lib/Cargo.toml
index 39fb717ca..9fcda5050 100644
--- a/crates/lib/Cargo.toml
+++ b/crates/lib/Cargo.toml
@@ -20,7 +20,7 @@ libquil = ["dep:libquil-sys"]
 cached = "0.44.0"
 enum-as-inner = "0.5.1"
 futures = "0.3.24"
-indexmap = "1.9.1"
+indexmap = "1.9.1, ||, ^2"
 lazy_static = "1.4.0"
 ndarray.workspace = true
 num = { version = "0.4.0", features = ["serde"] }