diff --git a/compiler/testData/codegen/box/size/add.kt b/compiler/testData/codegen/box/size/add.kt
index f97d9901fd9..3a160b4105d 100644
--- a/compiler/testData/codegen/box/size/add.kt
+++ b/compiler/testData/codegen/box/size/add.kt
@@ -1,6 +1,6 @@
 // TARGET_BACKEND: WASM
 
-// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 66_687 
+// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 65_583 
 // WASM_DCE_EXPECTED_OUTPUT_SIZE:  mjs  6_517 
 
 // FILE: test.kt
diff --git a/compiler/testData/codegen/box/size/helloWorld.kt b/compiler/testData/codegen/box/size/helloWorld.kt
index 5d20c36d3d2..a2c991f6d48 100644
--- a/compiler/testData/codegen/box/size/helloWorld.kt
+++ b/compiler/testData/codegen/box/size/helloWorld.kt
@@ -1,6 +1,6 @@
 // TARGET_BACKEND: WASM
 
-// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 67_012 
+// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 65_908 
 // WASM_DCE_EXPECTED_OUTPUT_SIZE:  mjs  6_458 
 
 fun box(): String {
diff --git a/compiler/testData/codegen/box/size/helloWorldDOM.kt b/compiler/testData/codegen/box/size/helloWorldDOM.kt
index 8a9da5f5e11..6963a039d00 100644
--- a/compiler/testData/codegen/box/size/helloWorldDOM.kt
+++ b/compiler/testData/codegen/box/size/helloWorldDOM.kt
@@ -1,6 +1,6 @@
 // TARGET_BACKEND: WASM
 
-// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 78_710 
+// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 77_603 
 // WASM_DCE_EXPECTED_OUTPUT_SIZE:  mjs  6_956 
 
 // FILE: test.kt
diff --git a/compiler/testData/codegen/box/size/ok.kt b/compiler/testData/codegen/box/size/ok.kt
index c7b903041f3..33c8ccfbc1e 100644
--- a/compiler/testData/codegen/box/size/ok.kt
+++ b/compiler/testData/codegen/box/size/ok.kt
@@ -1,6 +1,6 @@
 // TARGET_BACKEND: WASM
 
-// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 66_738 
+// WASM_DCE_EXPECTED_OUTPUT_SIZE: wasm 65_634 
 // WASM_DCE_EXPECTED_OUTPUT_SIZE:  mjs  6_389 
 
 fun box() = "OK"
\ No newline at end of file
diff --git a/libraries/kotlin.test/wasm/src/main/kotlin/kotlin/test/TeamcityAdapter.kt b/libraries/kotlin.test/wasm/src/main/kotlin/kotlin/test/TeamcityAdapter.kt
index c2f37400818..274f9584b03 100644
--- a/libraries/kotlin.test/wasm/src/main/kotlin/kotlin/test/TeamcityAdapter.kt
+++ b/libraries/kotlin.test/wasm/src/main/kotlin/kotlin/test/TeamcityAdapter.kt
@@ -77,17 +77,17 @@ internal class TeamcityAdapter : FrameworkAdapter {
         println("##teamcity[$type name='${name.tcEscape()}' message='${errorMessage.tcEscape()}' $flowId]")
     }
 
-
-    private lateinit var _testArguments: FrameworkTestArguments
-
+    private var _testArguments: FrameworkTestArguments? = null
     private val testArguments: FrameworkTestArguments
         get() {
-            if (!::_testArguments.isInitialized) {
+            var value = _testArguments
+            if (value == null) {
                 val arguments = d8Arguments().takeIf { it.isNotEmpty() } ?: nodeArguments()
-                _testArguments = FrameworkTestArguments.parse(arguments.split(' '))
+                value = FrameworkTestArguments.parse(arguments.split(' '))
+                _testArguments = value
             }
 
-            return _testArguments
+            return value
         }
 
     private fun runSuite(name: String, suiteFn: () -> Unit) {
diff --git a/libraries/stdlib/wasm/builtins/kotlin/Throwable.kt b/libraries/stdlib/wasm/builtins/kotlin/Throwable.kt
index 6452c98fcaa..54132d34d9c 100644
--- a/libraries/stdlib/wasm/builtins/kotlin/Throwable.kt
+++ b/libraries/stdlib/wasm/builtins/kotlin/Throwable.kt
@@ -24,13 +24,16 @@ public open class Throwable(open val message: String?, open val cause: kotlin.Th
 
     private val jsStack: ExternalInterfaceType = captureStackTrace()
 
-    private lateinit var _stack: String
+    private var _stack: String? = null
     internal val stack: String
         get() {
-            if (!::_stack.isInitialized) {
-                _stack = jsToKotlinStringAdapter(jsStack).removePrefix("Error\n")
+            var value = _stack
+            if (value == null) {
+                value = jsToKotlinStringAdapter(jsStack).removePrefix("Error\n")
+                _stack = value
             }
-            return _stack
+
+            return value
         }
 
     internal var suppressedExceptionsList: MutableList<Throwable>? = null
diff --git a/libraries/stdlib/wasm/internal/kotlin/wasm/internal/ExternalWrapper.kt b/libraries/stdlib/wasm/internal/kotlin/wasm/internal/ExternalWrapper.kt
index 022407a37ba..f26cefbe3dd 100644
--- a/libraries/stdlib/wasm/internal/kotlin/wasm/internal/ExternalWrapper.kt
+++ b/libraries/stdlib/wasm/internal/kotlin/wasm/internal/ExternalWrapper.kt
@@ -281,28 +281,40 @@ private fun getJsTrue(): JsBoolean =
 private fun getJsFalse(): JsBoolean =
     js("false")
 
-private lateinit var _jsEmptyString: JsString 
+private var _jsEmptyString: JsString? = null
 private val jsEmptyString: JsString
     get() {
-        if (!::_jsEmptyString.isInitialized)
-            _jsEmptyString = getJsEmptyString()
-        return _jsEmptyString
+        var value = _jsEmptyString
+        if (value == null) {
+            value = getJsEmptyString()
+            _jsEmptyString = value
+        }
+
+        return value
     }
 
-private lateinit var _jsTrue: JsBoolean
+private var _jsTrue: JsBoolean? = null
 private val jsTrue: JsBoolean
     get() {
-        if (!::_jsTrue.isInitialized)
-            _jsTrue = getJsTrue()
-        return _jsTrue
+        var value = _jsTrue
+        if (value == null) {
+            value = getJsTrue()
+            _jsTrue = value
+        }
+
+        return value
     }
 
-private lateinit var _jsFalse: JsBoolean
-private val jsFalse: JsBoolean 
+private var _jsFalse: JsBoolean? = null
+private val jsFalse: JsBoolean
     get() {
-        if (!::_jsFalse.isInitialized)
-            _jsFalse = getJsFalse()
-        return _jsFalse
+        var value = _jsFalse
+        if (value == null) {
+            value = getJsFalse()
+            _jsFalse = value
+        }
+
+        return value
     }
 
 internal fun numberToDoubleAdapter(x: Number): Double =