diff --git a/src/compiler/iroptimizer.js b/src/compiler/iroptimizer.js
index ae7d98e495..481bccd5b7 100644
--- a/src/compiler/iroptimizer.js
+++ b/src/compiler/iroptimizer.js
@@ -158,16 +158,36 @@ class IROptimizer {
         case InputOpcode.ADDON_CALL:
             break;
 
+        case InputOpcode.CAST_BOOLEAN: {
+            const innerType = inputs.target.type;
+            if (innerType & InputType.BOOLEAN) return innerType;
+            return InputType.BOOLEAN;
+        }
+
         case InputOpcode.CAST_NUMBER: {
             const innerType = inputs.target.type;
             if (innerType & InputType.NUMBER) return innerType;
             return InputType.NUMBER;
-        } case InputOpcode.CAST_NUMBER_OR_NAN: {
+        }
+
+        case InputOpcode.CAST_NUMBER_INDEX: {
+            const innerType = inputs.target.type;
+            if (innerType & InputType.NUMBER_INDEX) return innerType;
+            return InputType.NUMBER_INDEX;
+        }
+
+        case InputOpcode.CAST_NUMBER_OR_NAN: {
             const innerType = inputs.target.type;
             if (innerType & InputType.NUMBER_OR_NAN) return innerType;
             return InputType.NUMBER_OR_NAN;
         }
 
+        case InputOpcode.CAST_STRING: {
+            const innerType = inputs.target.type;
+            if (innerType & InputType.STRING) return innerType;
+            return InputType.STRING;
+        }
+
         case InputOpcode.OP_ADD: {
             const leftType = inputs.left.type;
             const rightType = inputs.right.type;
@@ -693,19 +713,45 @@ class IROptimizer {
         }
 
         switch (input.opcode) {
+        case InputOpcode.CAST_BOOLEAN: {
+            const targetType = input.inputs.target.type;
+            if ((targetType & InputType.BOOLEAN) === targetType) {
+                return input.inputs.target;
+            }
+            return input;
+        }
+
         case InputOpcode.CAST_NUMBER: {
             const targetType = input.inputs.target.type;
             if ((targetType & InputType.NUMBER) === targetType) {
                 return input.inputs.target;
             }
             return input;
-        } case InputOpcode.CAST_NUMBER_OR_NAN: {
+        }
+
+        case InputOpcode.CAST_NUMBER_INDEX: {
+            const targetType = input.inputs.target.type;
+            if ((targetType & InputType.NUMBER_INDEX) === targetType) {
+                return input.inputs.target;
+            }
+            return input;
+        }
+
+        case InputOpcode.CAST_NUMBER_OR_NAN: {
             const targetType = input.inputs.target.type;
             if ((targetType & InputType.NUMBER_OR_NAN) === targetType) {
                 return input.inputs.target;
             }
             return input;
         }
+
+        case InputOpcode.CAST_STRING: {
+            const targetType = input.inputs.target.type;
+            if ((targetType & InputType.STRING) === targetType) {
+                return input.inputs.target;
+            }
+            return input;
+        }
         }
 
         return input;
diff --git a/test/snapshot/__snapshots__/tw-sensing-of.sb3.tw-snapshot b/test/snapshot/__snapshots__/tw-sensing-of.sb3.tw-snapshot
index a370af3e46..b15bc894fa 100644
--- a/test/snapshot/__snapshots__/tw-sensing-of.sb3.tw-snapshot
+++ b/test/snapshot/__snapshots__/tw-sensing-of.sb3.tw-snapshot
@@ -52,7 +52,7 @@ if (compareEqual((b4 ? b4.value : 0), 0)) {
 yield* executeInCompatibilityLayer({"MESSAGE":"pass non existent variable",}, b0, false, false, ")nnN?*l+E)dC(fT5(_@q", null);
 }
 b5.value = (("" + randomInt(1, 9)) + ("" + randomInt(1, 9)));
-if (compareEqual(runtime.ext_scratch3_sensing.getAttributeOf({OBJECT: ("" + b5.value), PROPERTY: "backdrop #" }), 0)) {
+if (compareEqual(runtime.ext_scratch3_sensing.getAttributeOf({OBJECT: b5.value, PROPERTY: "backdrop #" }), 0)) {
 yield* executeInCompatibilityLayer({"MESSAGE":"pass NE backdrop #",}, b0, false, false, "UFr{fbR3@a.u_paq:r]F", null);
 }
 if (compareEqual(runtime.ext_scratch3_sensing.getAttributeOf({OBJECT: ("" + b5.value), PROPERTY: "backdrop name" }), 0)) {
diff --git a/test/snapshot/__snapshots__/tw-simple-string-operations.sb3.tw-snapshot b/test/snapshot/__snapshots__/tw-simple-string-operations.sb3.tw-snapshot
index 78cdbd86e7..7899f9ed37 100644
--- a/test/snapshot/__snapshots__/tw-simple-string-operations.sb3.tw-snapshot
+++ b/test/snapshot/__snapshots__/tw-simple-string-operations.sb3.tw-snapshot
@@ -24,11 +24,11 @@ return function funXYZ_a () {
 b0.value = "ababa";
 b1.value = "";
 b2.value = 1;
-for (var a0 = ("" + b0.value).length; a0 > 0; a0--) {
-if ((((("" + b0.value))[(b2.value | 0) - 1] || "").toLowerCase() === "a".toLowerCase())) {
-b1.value = (("" + b1.value) + "b");
+for (var a0 = b0.value.length; a0 > 0; a0--) {
+if ((((b0.value)[b2.value - 1] || "").toLowerCase() === "a".toLowerCase())) {
+b1.value = (b1.value + "b");
 } else {
-b1.value = (("" + b1.value) + "a");
+b1.value = (b1.value + "a");
 }
 b2.value = (b2.value + 1);
 }
diff --git a/test/snapshot/__snapshots__/warp-timer/tw-sensing-of.sb3.tw-snapshot b/test/snapshot/__snapshots__/warp-timer/tw-sensing-of.sb3.tw-snapshot
index a370af3e46..b15bc894fa 100644
--- a/test/snapshot/__snapshots__/warp-timer/tw-sensing-of.sb3.tw-snapshot
+++ b/test/snapshot/__snapshots__/warp-timer/tw-sensing-of.sb3.tw-snapshot
@@ -52,7 +52,7 @@ if (compareEqual((b4 ? b4.value : 0), 0)) {
 yield* executeInCompatibilityLayer({"MESSAGE":"pass non existent variable",}, b0, false, false, ")nnN?*l+E)dC(fT5(_@q", null);
 }
 b5.value = (("" + randomInt(1, 9)) + ("" + randomInt(1, 9)));
-if (compareEqual(runtime.ext_scratch3_sensing.getAttributeOf({OBJECT: ("" + b5.value), PROPERTY: "backdrop #" }), 0)) {
+if (compareEqual(runtime.ext_scratch3_sensing.getAttributeOf({OBJECT: b5.value, PROPERTY: "backdrop #" }), 0)) {
 yield* executeInCompatibilityLayer({"MESSAGE":"pass NE backdrop #",}, b0, false, false, "UFr{fbR3@a.u_paq:r]F", null);
 }
 if (compareEqual(runtime.ext_scratch3_sensing.getAttributeOf({OBJECT: ("" + b5.value), PROPERTY: "backdrop name" }), 0)) {