diff --git a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
index 35e2743a914..750baeb72a4 100644
--- a/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
+++ b/compiler/ir/backend.wasm/src/org/jetbrains/kotlin/backend/wasm/ir2wasm/BodyGenerator.kt
@@ -864,6 +864,8 @@ class BodyGenerator(
                                 WasmImmediate.MemArg(0u, 0u)
                             WasmImmediateKind.STRUCT_TYPE_IDX ->
                                 WasmImmediate.GcType(getReferenceGcType())
+                            WasmImmediateKind.HEAP_TYPE ->
+                                WasmImmediate.HeapType(WasmHeapType.Type(getReferenceGcType()))
                             WasmImmediateKind.TYPE_IDX ->
                                 WasmImmediate.TypeIdx(getReferenceGcType())
 
diff --git a/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt b/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt
index 17ba95bcb60..d2bd496535f 100644
--- a/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt
+++ b/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/Operators.kt
@@ -372,19 +372,19 @@ enum class WasmOp(
     I31_GET_U("i31.get_u", 0xFB_22),
 
     REF_EQ("ref.eq", 0xD5),
-    REF_TEST("ref.test", 0xFB_40, STRUCT_TYPE_IDX),
-    REF_TEST_NULL("ref.test null", 0xFB_48, STRUCT_TYPE_IDX),
-    REF_CAST("ref.cast", 0xFB_41, STRUCT_TYPE_IDX),
-    REF_CAST_NULL("ref.cast null", 0xFB_49, STRUCT_TYPE_IDX),
+    REF_TEST("ref.test", 0xFB_40, HEAP_TYPE),
+    REF_TEST_NULL("ref.test null", 0xFB_48, HEAP_TYPE),
+    REF_CAST("ref.cast", 0xFB_41, HEAP_TYPE),
+    REF_CAST_NULL("ref.cast null", 0xFB_49, HEAP_TYPE),
 
     // TODO remove as soon as V8 support new instructions, see below
     BR_ON_CAST_FAIL("br_on_cast_fail", 0xfb47, listOf(LABEL_IDX, STRUCT_TYPE_IDX)),
 
 // Not yet supported by V8
-//    BR_ON_CAST("br_on_cast", 0xFB42, listOf(LABEL_IDX, STRUCT_TYPE_IDX)),
-//    BR_ON_CAST_NULL("br_on_cast null", 0xFB4A, listOf(LABEL_IDX, STRUCT_TYPE_IDX)),
-//    BR_ON_CAST_FAIL("br_on_cast_fail", 0xFB43, listOf(LABEL_IDX, STRUCT_TYPE_IDX)),
-//    BR_ON_CAST_FAIL_NULL("br_on_cast_fail null", 0xFB4B, listOf(LABEL_IDX, STRUCT_TYPE_IDX)),
+//    BR_ON_CAST("br_on_cast", 0xFB42, listOf(LABEL_IDX, HEAP_TYPE)),
+//    BR_ON_CAST_NULL("br_on_cast null", 0xFB4A, listOf(LABEL_IDX, HEAP_TYPE)),
+//    BR_ON_CAST_FAIL("br_on_cast_fail", 0xFB43, listOf(LABEL_IDX, HEAP_TYPE)),
+//    BR_ON_CAST_FAIL_NULL("br_on_cast_fail null", 0xFB4B, listOf(LABEL_IDX, HEAP_TYPE)),
 
     EXTERN_INTERNALIZE("extern.internalize", 0xfb70), // externref -> anyref
     EXTERN_EXTERNALIZE("extern.externalize", 0xfb71), // anyref -> externref
diff --git a/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/WasmExpressionBuilder.kt b/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/WasmExpressionBuilder.kt
index 4b0a5b0c600..634a6bb7363 100644
--- a/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/WasmExpressionBuilder.kt
+++ b/wasm/wasm.ir/src/org/jetbrains/kotlin/wasm/ir/WasmExpressionBuilder.kt
@@ -157,11 +157,11 @@ abstract class WasmExpressionBuilder {
     }
 
     fun buildRefCastNullStatic(toType: WasmSymbolReadOnly<WasmTypeDeclaration>) {
-        buildInstr(WasmOp.REF_CAST_NULL, WasmImmediate.TypeIdx(toType))
+        buildInstr(WasmOp.REF_CAST_NULL, WasmImmediate.HeapType(WasmHeapType.Type(toType)))
     }
 
     fun buildRefTestStatic(toType: WasmSymbolReadOnly<WasmTypeDeclaration>) {
-        buildInstr(WasmOp.REF_TEST, WasmImmediate.TypeIdx(toType))
+        buildInstr(WasmOp.REF_TEST, WasmImmediate.HeapType(WasmHeapType.Type(toType)))
     }
 
     fun buildRefNull(type: WasmHeapType) {