diff --git a/incremental/common/src/KoalaProfiler.ts b/incremental/common/src/KoalaProfiler.ts
index 3eba324d8ed29b526e06490aaf2573e77afbc55e..d7f31ea58db2234d3bcea51172d5dd2447850b46 100644
--- a/incremental/common/src/KoalaProfiler.ts
+++ b/incremental/common/src/KoalaProfiler.ts
@@ -131,9 +131,9 @@ export class KoalaProfiler {
             `layouts: ${this.layouts}`,
             `FPS: ${this.lastFPS}`,
         )
-        KoalaProfiler.map?.forEach((set:Set<Object>, kind:int32) => {
+        KoalaProfiler.map ? KoalaProfiler.map!.forEach((set:Set<Object>, kind:int32) => {
             if (set.size > 0) array.push(kind + ":" + set.size)
-        })
+        }) : undefined
         return array.join("\n")
     }
 
diff --git a/incremental/common/src/MarkableQueue.ts b/incremental/common/src/MarkableQueue.ts
index 99adf2fbd4a5540335fc21d4de58185d1d7bff5b..6f4090081e7752f8be723f2b5deaf524dff761ef 100644
--- a/incremental/common/src/MarkableQueue.ts
+++ b/incremental/common/src/MarkableQueue.ts
@@ -58,7 +58,8 @@ class DefaultQueue implements MarkableQueue {
         if (marker) {
             let block = this.first.getAndSet(marker)
             while (block !== marker) {
-                block.callback?.()
+                const callback = block.callback
+                if (callback != undefined) callback!()
                 block = block.next.value!
             }
         }
@@ -90,7 +91,8 @@ class ReversedQueue implements MarkableQueue {
         if (marker) {
             let block = marker.next.getAndSet(undefined)
             while (block) {
-                block!.callback?.()
+                const callback = block!.callback
+                if (callback != undefined) block!.callback!()
                 block = block!.next.value
             }
         }
diff --git a/incremental/common/src/math.ts b/incremental/common/src/math.ts
index 8827d8d7b5e5b5268775bc36c557eb384f6db8f1..bf657ce67298c7fd760fb73213356306c34b20f5 100644
--- a/incremental/common/src/math.ts
+++ b/incremental/common/src/math.ts
@@ -68,7 +68,7 @@ export function parseNumber(str: string, name: string = "number", verify: boolea
         const value = asFloat64(str)
         if (verify) {
             const reverseStr = asString(value)
-            if (reverseStr !== undefined && reverseStr?.length == str.length && reverseStr == str) {
+            if (reverseStr !== undefined && (reverseStr ? reverseStr!.length : undefined) == str.length && reverseStr == str) {
                 return value
             }
         }
diff --git a/incremental/compat/src/arkts/observable.ts b/incremental/compat/src/arkts/observable.ts
index 7a6cd65b33a309bd8c92a4909d0403695240f0a8..ae725fc224d1addf252cb8c99af35fa23a526149 100644
--- a/incremental/compat/src/arkts/observable.ts
+++ b/incremental/compat/src/arkts/observable.ts
@@ -58,7 +58,7 @@ export class ObservableHandler implements Observable {
             while (true) {
                 const result = it.next()
                 if (result.done) break
-                result.value?.onAccess()
+                result.value ? result.value!.onAccess() : undefined
             }
         }
     }
@@ -73,7 +73,7 @@ export class ObservableHandler implements Observable {
                 while (true) {
                     const result = it.next()
                     if (result.done) break
-                    result.value?.onModify()
+                    result.value ? result.value!.onModify() : undefined
                 }
             }
         })
diff --git a/incremental/runtime/src/states/Disposable.ts b/incremental/runtime/src/states/Disposable.ts
index 81bdb2c36c21b63a16429bfcb24018b1706ff172..e29e41b33c828143864a361b4c5c0b93d016dde8 100644
--- a/incremental/runtime/src/states/Disposable.ts
+++ b/incremental/runtime/src/states/Disposable.ts
@@ -34,7 +34,8 @@ export interface Disposable {
 export function disposeContentForward<Type extends Disposable>(array: ReadonlyArray<Type | undefined>) {
     const length = array.length
     for (let i = 0; i < length; i++) {
-        array[i]?.dispose()
+        const ith = array[i]
+        ith ? ith!.dispose() : undefined
     }
 }
 
@@ -44,7 +45,8 @@ export function disposeContentForward<Type extends Disposable>(array: ReadonlyAr
 export function disposeContentBackward<Type extends Disposable>(array: ReadonlyArray<Type | undefined>) {
     let i = array.length
     while (0 < i--) {
-        array[i]?.dispose()
+        const ith = array[i]
+        ith ? ith!.dispose() : undefined
     }
 }
 
@@ -55,6 +57,6 @@ export function disposeContent<Type extends Disposable>(it: IterableIterator<Typ
     while (true) {
         const result = it.next()
         if (result.done) break
-        result.value?.dispose()
+        result.value ? result.value!.dispose() : undefined
     }
 }
diff --git a/incremental/runtime/src/states/GlobalStateManager.ts b/incremental/runtime/src/states/GlobalStateManager.ts
index fed60f1cf51534e7c25fbd4e18488c2621f10127..70c07496faa7e8f44c593463ecc4e1b6e11cc570 100644
--- a/incremental/runtime/src/states/GlobalStateManager.ts
+++ b/incremental/runtime/src/states/GlobalStateManager.ts
@@ -40,7 +40,7 @@ export class GlobalStateManager {
      * @internal
      */
     static reset() {
-        GlobalStateManager.current?.reset()
+        GlobalStateManager.current ? GlobalStateManager.current!.reset() : undefined
     }
 }
 
diff --git a/incremental/runtime/src/states/Journal.ts b/incremental/runtime/src/states/Journal.ts
index dc11866949fee4d9f0a8f806a415ebe38881bc55..77d2d860222e20d9462ac975ee17771f7ef6f98e 100644
--- a/incremental/runtime/src/states/Journal.ts
+++ b/incremental/runtime/src/states/Journal.ts
@@ -90,7 +90,8 @@ export class Journal implements Changes {
         const chunk = this.current.value
         const change = chunk.get<Array<Item>>(state)
         if (change) return change.value
-        const copy = Array.from<Item>(find<Array<Item>>(state, chunk.previous.value)?.value ?? array)
+        const found = find<Array<Item>>(state, chunk.previous.value)
+        const copy = Array.from<Item>(found ? found!.value : array)
         chunk.map.set(state, new AtomicRef<Array<Item>>(copy))
         return copy
     }
@@ -132,9 +133,9 @@ class Chunk {
  */
 function find<Value>(state: Object, chunk?: Chunk): AtomicRef<Value> | undefined {
     while (chunk) {
-        const change = chunk?.get<Value>(state)
+        const change = chunk ? chunk!.get<Value>(state) : undefined
         if (change) return change
-        chunk = chunk?.previous.value
+        chunk = chunk ? chunk!.previous.value : undefined
     }
     return undefined
 }
diff --git a/incremental/runtime/src/tree/IncrementalNode.ts b/incremental/runtime/src/tree/IncrementalNode.ts
index 198c7073b04c8ac2f35d4151117be76768f5097e..1d03b3f879f3c12da4af593bef1c5d721c46557d 100644
--- a/incremental/runtime/src/tree/IncrementalNode.ts
+++ b/incremental/runtime/src/tree/IncrementalNode.ts
@@ -121,7 +121,7 @@ export class IncrementalNode implements Disposable, ReadonlyTreeNode {
             if (parent._child === this) {
                 parent._child = next
             }
-            parent.onChildRemoved?.(this)
+            parent.onChildRemoved ? parent.onChildRemoved!(this) : undefined
         }
     }
 
@@ -217,7 +217,7 @@ export class IncrementalNode implements Disposable, ReadonlyTreeNode {
                 // TODO: this is to workaround ast dumper bug #24055
                 if (0) {} else {}
 
-                parent.onChildInserted?.(this)
+                parent.onChildInserted ? parent.onChildInserted!(this) : undefined
             }
         }
     }