diff --git a/compiler/can/src/builtins.rs b/compiler/can/src/builtins.rs
index 96b2e1c21d..2b2ee02c2e 100644
--- a/compiler/can/src/builtins.rs
+++ b/compiler/can/src/builtins.rs
@@ -78,6 +78,7 @@ pub fn builtin_defs_map(symbol: Symbol, var_store: &mut VarStore) -> Option<Def>
         LIST_KEEP_IF => list_keep_if,
         LIST_WALK => list_walk,
         LIST_WALK_BACKWARDS => list_walk_backwards,
+        DICT_SIZE => dict_size,
         NUM_ADD => num_add,
         NUM_ADD_CHECKED => num_add_checked,
         NUM_ADD_WRAP => num_add_wrap,
@@ -1755,7 +1756,7 @@ fn list_keep_if(symbol: Symbol, var_store: &mut VarStore) -> Def {
     )
 }
 
-// List.contains : List elem, elem, -> Bool
+/// List.contains : List elem, elem -> Bool
 fn list_contains(symbol: Symbol, var_store: &mut VarStore) -> Def {
     let list_var = var_store.fresh();
     let elem_var = var_store.fresh();
@@ -1803,6 +1804,26 @@ fn list_map(symbol: Symbol, var_store: &mut VarStore) -> Def {
     )
 }
 
+/// Dict.size : Dict * * -> Nat
+fn dict_size(symbol: Symbol, var_store: &mut VarStore) -> Def {
+    let size_var = var_store.fresh();
+    let dict_var = var_store.fresh();
+
+    let body = RunLowLevel {
+        op: LowLevel::DictSize,
+        args: vec![(dict_var, Var(Symbol::ARG_1))],
+        ret_var: size_var,
+    };
+
+    defn(
+        symbol,
+        vec![(dict_var, Symbol::ARG_1)],
+        var_store,
+        body,
+        size_var,
+    )
+}
+
 /// Num.rem : Int, Int -> Result Int [ DivByZero ]*
 fn num_rem(symbol: Symbol, var_store: &mut VarStore) -> Def {
     let num_var = var_store.fresh();
diff --git a/compiler/gen/tests/gen_dict.rs b/compiler/gen/tests/gen_dict.rs
index 307dad1646..a83fc01306 100644
--- a/compiler/gen/tests/gen_dict.rs
+++ b/compiler/gen/tests/gen_dict.rs
@@ -12,8 +12,7 @@ extern crate roc_gen;
 mod helpers;
 
 #[cfg(test)]
-mod gen_hash {
-
+mod gen_dict {
     #[test]
     fn dict_empty_len() {
         assert_evals_to!(
diff --git a/compiler/gen/tests/gen_hash.rs b/compiler/gen/tests/gen_hash.rs
index d863c85ef3..fc577d16e6 100644
--- a/compiler/gen/tests/gen_hash.rs
+++ b/compiler/gen/tests/gen_hash.rs
@@ -13,6 +13,10 @@ mod gen_hash {
 
     #[test]
     fn basic_hash() {
-        let value = env.builder;
+
+        // assert_llvm_evals_to(
+        //
+        // )
+        // let value = env.builder;
     }
 }