diff --git a/src/compiler/blocks/compiler_compat.js b/src/compiler/blocks/compiler_compat.js
index ab271098..adf9b212 100644
--- a/src/compiler/blocks/compiler_compat.js
+++ b/src/compiler/blocks/compiler_compat.js
@@ -95,5 +95,5 @@ const statementCompat = /** @param {StatementUtil} util */ (util) => {
 };
 
 const inputCompat = /** @param {InputUtil} util */ (util) => {
-    return util.unknown(generateCompatCall(util));
+    return util.unknown('(' + generateCompatCall(util) + ')');
 };
diff --git a/src/compiler/blocks/compiler_scratch3_data.js b/src/compiler/blocks/compiler_scratch3_data.js
index 758bd484..2cbc0ece 100644
--- a/src/compiler/blocks/compiler_scratch3_data.js
+++ b/src/compiler/blocks/compiler_scratch3_data.js
@@ -28,6 +28,7 @@ module.exports.getInputs = () => {
         data_lengthoflist: lengthOfList,
         data_itemoflist: itemOfList,
         data_listcontainsitem: listContainsItem,
+        data_itemnumoflist: itemNumOfList,
     };
 };
 
@@ -189,3 +190,9 @@ const listContainsItem = /** @param {InputUtil} util */ (util) => {
     const ITEM = util.input('ITEM');
     return util.boolean(`listContains(${LIST}, ${ITEM})`);
 };
+
+const itemNumOfList = /** @param {InputUtil} util */ (util) => {
+    const LIST = listReference(util);
+    const ITEM = util.input('ITEM');
+    return util.number(`listIndexOf(${LIST}, ${ITEM})`);
+};
diff --git a/src/compiler/compiler.js b/src/compiler/compiler.js
index 78fd1254..053a9e27 100644
--- a/src/compiler/compiler.js
+++ b/src/compiler/compiler.js
@@ -616,7 +616,12 @@ class Compiler {
 
                 const compiledProcedure = this.compileScript(bodyStart, hints);
                 this.procedures[procedureCode] = compiledProcedure;
-                this.blocks._cache.compiledProcedures[procedureCode] = compiledProcedure;
+            }
+        }
+
+        for (const procedureCode of Object.keys(this.procedures)) {
+            if (!this.blocks._cache.compiledProcedures.hasOwnProperty(procedureCode)) {
+                this.blocks._cache.compiledProcedures[procedureCode] = this.procedures[procedureCode];
             }
         }
 
diff --git a/src/compiler/execute.js b/src/compiler/execute.js
index cb468b6c..9560686a 100644
--- a/src/compiler/execute.js
+++ b/src/compiler/execute.js
@@ -241,7 +241,7 @@ const ioQuery = (device, func, args) => {
 
 /**
  * Create and start a timer.
- * @returns {Timer}
+ * @returns {Timer} A started timer
  */
 const timer = () => {
     const timer = new Timer();
@@ -283,6 +283,7 @@ var listIndex = (index, length) => {
  * Get a value from a list.
  * @param {import('../engine/variable')} list The list
  * @param {*} idx The 1-indexed index in the list.
+ * @returns The list item, otherwise empty string if it does not exist.
  */
 const listGet = (list, idx) => {
     const index = listIndex(idx, list.value.length);
@@ -310,8 +311,8 @@ const listReplace = (list, idx, value) => {
 /**
  * Insert a value in a list.
  * @param {import('../engine/variable')} list The list.
- * @param {any} idx The Scratch index in the list.
- * @param {any} value The value to insert.
+ * @param {*} idx The Scratch index in the list.
+ * @param {*} value The value to insert.
  */
 const listInsert = (list, idx, value) => {
     const index = listIndex(idx, list.value.length + 1);
@@ -325,7 +326,7 @@ const listInsert = (list, idx, value) => {
 /**
  * Delete a value from a list.
  * @param {import('../engine/variable')} list The list.
- * @param {any} idx The Scratch index in the list.
+ * @param {*} idx The Scratch index in the list.
  */
 const listDelete = (list, idx) => {
     if (idx === 'all') {
@@ -343,8 +344,8 @@ const listDelete = (list, idx) => {
 /**
  * Return whether a list contains a value.
  * @param {import('../engine/variable')} list The list.
- * @param {any} item The value to search for.
- * @returns {boolean}
+ * @param {*} item The value to search for.
+ * @returns {boolean} True if the list contains the item
  */
 const listContains = (list, item) => {
     // TODO: evaluate whether indexOf is worthwhile here
@@ -359,6 +360,21 @@ const listContains = (list, item) => {
     return false;
 };
 
+/**
+ * Find the 1-indexed index of an item in a list.
+ * @param {import('../engine/variable')} list The list.
+ * @param {*} item The item to search for
+ * @returns {number} The 1-indexed index of the item in the list, otherwise 0
+ */
+const listIndexOf = (list, item) => {
+    for (var i = 0; i < list.value.length; i++) {
+        if (compare(list.value[i], item) === 0) {
+            return i + 1;
+        }
+    }
+    return 0;
+};
+
 /**
  * Implements Scratch modulo (floored division instead of truncated division)
  * @param {number} n