diff --git a/src/compiler/irgen.js b/src/compiler/irgen.js
index 45f37351..9d47740e 100644
--- a/src/compiler/irgen.js
+++ b/src/compiler/irgen.js
@@ -1291,33 +1291,43 @@ class ScriptTreeGenerator {
         const procedureCode = block.mutation.proccode;
         const paramNamesIdsAndDefaults = this.blocks.getProcedureParamNamesIdsAndDefaults(procedureCode);
         if (paramNamesIdsAndDefaults === null) {
+            // Still need to evaluate arguments in case of side effects
+            const argumentList = [];
+            for (const inputName of Object.keys(block.inputs)) {
+                argumentList.push(this.descendInputOfBlock(block, inputName));
+            }
             return {
-                kind: 'noop'
+                kind: 'procedures.discard',
+                values: argumentList
             };
         }
 
         const [paramNames, paramIds, paramDefaults] = paramNamesIdsAndDefaults;
+        const argumentList = [];
+        for (let i = 0; i < paramIds.length; i++) {
+            let value;
+            if (block.inputs[paramIds[i]] && block.inputs[paramIds[i]].block) {
+                value = this.descendInputOfBlock(block, paramIds[i]);
+            } else {
+                value = {
+                    kind: 'constant',
+                    value: paramDefaults[i]
+                };
+            }
+            argumentList.push(value);
+        }
 
         const addonBlock = this.runtime.getAddonBlock(procedureCode);
         if (addonBlock) {
             this.script.yields = true;
-            const args = {};
-            for (let i = 0; i < paramIds.length; i++) {
-                let value;
-                if (block.inputs[paramIds[i]] && block.inputs[paramIds[i]].block) {
-                    value = this.descendInputOfBlock(block, paramIds[i]);
-                } else {
-                    value = {
-                        kind: 'constant',
-                        value: paramDefaults[i]
-                    };
-                }
-                args[paramNames[i]] = value;
+            const argumentNameMap = {};
+            for (let i = 0; i < argumentList.length; i++) {
+                argumentNameMap[paramNames[i]] = argumentList[i];
             }
             return {
                 kind: 'addons.call',
                 code: procedureCode,
-                arguments: args,
+                arguments: argumentNameMap,
                 blockId: block.id
             };
         }
@@ -1326,7 +1336,8 @@ class ScriptTreeGenerator {
         const definitionBlock = this.blocks.getBlock(definitionId);
         if (!definitionBlock) {
             return {
-                kind: 'noop'
+                kind: 'procedures.discard',
+                values: argumentList
             };
         }
         const innerDefinition = this.blocks.getBlock(definitionBlock.inputs.custom_block.block);
@@ -1350,31 +1361,15 @@ class ScriptTreeGenerator {
         }
 
         // Non-warp direct recursion yields.
-        if (!this.script.isWarp) {
-            if (procedureCode === this.script.procedureCode) {
-                this.script.yields = true;
-            }
-        }
-
-        const args = [];
-        for (let i = 0; i < paramIds.length; i++) {
-            let value;
-            if (block.inputs[paramIds[i]] && block.inputs[paramIds[i]].block) {
-                value = this.descendInputOfBlock(block, paramIds[i]);
-            } else {
-                value = {
-                    kind: 'constant',
-                    value: paramDefaults[i]
-                };
-            }
-            args.push(value);
+        if (!this.script.isWarp && procedureCode === this.script.procedureCode) {
+            this.script.yields = true;
         }
 
         return {
             kind: 'procedures.call',
             code: procedureCode,
             variant,
-            arguments: args
+            arguments: argumentList
         };
     }
 
diff --git a/src/compiler/jsgen.js b/src/compiler/jsgen.js
index f20b460c..c56b4ca2 100644
--- a/src/compiler/jsgen.js
+++ b/src/compiler/jsgen.js
@@ -653,6 +653,17 @@ class JSGenerator {
             }
             return new TypedInput(`${procedureReference}(${joinedArgs})`, TYPE_UNKNOWN);
         }
+        case 'procedures.discard': {
+            const args = [];
+            for (const value of node.values) {
+                args.push(this.descendInput(value).asUnknown());
+            }
+            if (args.length > 0) {
+                // We can use the comma operator to discard the values.
+                return new TypedInput(`(${args.join(',')},"")`, TYPE_STRING);
+            }
+            return new TypedInput('""', TYPE_STRING);
+        }
 
         case 'sensing.answer':
             return new TypedInput(`runtime.ext_scratch3_sensing._answer`, TYPE_STRING);
@@ -1068,6 +1079,14 @@ class JSGenerator {
             this.resetVariableInputs();
             break;
         }
+        case 'procedures.discard': {
+            for (const value of node.values) {
+                const input = this.descendInput(value).asUnknown();
+                // Don't need to use void, but it makes it explicit that we do not care about the result.
+                this.source += `void ${input};\n`;
+            }
+            break;
+        }
         case 'procedures.return':
             this.stopScriptAndReturn(this.descendInput(node.value).asSafe());
             break;