diff --git a/compiler/mono/src/alias_analysis.rs b/compiler/mono/src/alias_analysis.rs
index 5a06dd23cd..7b3f623c72 100644
--- a/compiler/mono/src/alias_analysis.rs
+++ b/compiler/mono/src/alias_analysis.rs
@@ -19,19 +19,22 @@ pub const STATIC_STR_NAME: ConstName = ConstName(&Symbol::STR_ALIAS_ANALYSIS_STA
 
 const ENTRY_POINT_NAME: &[u8] = b"mainForHost";
 
-pub fn func_name_bytes(proc: &Proc) -> [u8; 16] {
+pub fn func_name_bytes(proc: &Proc) -> [u8; SIZE] {
     func_name_bytes_help(proc.name, proc.args.iter().map(|x| x.0), proc.ret_layout)
 }
 
+const DEBUG: bool = false;
+const SIZE: usize = if DEBUG { 50 } else { 16 };
+
 pub fn func_name_bytes_help<'a, I>(
     symbol: Symbol,
     argument_layouts: I,
     return_layout: Layout<'a>,
-) -> [u8; 16]
+) -> [u8; SIZE]
 where
     I: Iterator<Item = Layout<'a>>,
 {
-    let mut name_bytes = [0u8; 16];
+    let mut name_bytes = [0u8; SIZE];
 
     use std::collections::hash_map::DefaultHasher;
     use std::hash::Hash;
@@ -75,6 +78,12 @@ where
         *target = *source;
     }
 
+    if DEBUG {
+        for (i, c) in (format!("{:?}", symbol)).chars().take(25).enumerate() {
+            name_bytes[25 + i] = c as u8;
+        }
+    }
+
     name_bytes
 }
 
@@ -127,8 +136,6 @@ where
 
         // all other functions
         for proc in procs {
-            let spec = proc_spec(proc)?;
-
             let bytes = func_name_bytes(proc);
             let func_name = FuncName(&bytes);
             eprintln!(
@@ -138,6 +145,8 @@ where
                 proc.args.len()
             );
 
+            let spec = proc_spec(proc)?;
+
             m.add_func(func_name, spec)?;
         }
 
@@ -457,7 +466,7 @@ fn call_spec(
         ),
         HigherOrderLowLevel {
             specialization_id,
-            closure_layout: _,
+            closure_env_layout,
             op,
             arg_layouts,
             ret_layout,
@@ -507,6 +516,24 @@ fn call_spec(
                         builder.add_call(block, spec_var, module, name, argument)?;
                     }
 
+                    ListWalk | ListWalkBackwards | ListWalkUntil => {
+                        let list = env.symbols[&call.arguments[0]];
+                        let default = env.symbols[&call.arguments[1]];
+                        let closure_env = env.symbols[&call.arguments[3]];
+
+                        let bag = builder.add_get_tuple_field(block, list, LIST_BAG_INDEX)?;
+                        let _cell = builder.add_get_tuple_field(block, list, LIST_CELL_INDEX)?;
+
+                        let first = builder.add_bag_get(block, bag)?;
+
+                        let argument = if closure_env_layout.is_none() {
+                            builder.add_make_tuple(block, &[first, default])?
+                        } else {
+                            builder.add_make_tuple(block, &[first, default, closure_env])?
+                        };
+                        builder.add_call(block, spec_var, module, name, argument)?;
+                    }
+
                     ListMapWithIndex => {
                         let list = env.symbols[&call.arguments[0]];