diff --git a/src/heap/heap.cc b/src/heap/heap.cc
index 7aa1a53319..19d35c4e7a 100644
--- a/src/heap/heap.cc
+++ b/src/heap/heap.cc
@@ -108,7 +108,7 @@ bool Heap::GCCallbackTuple::operator==(
 }
 
 Heap::GCCallbackTuple& Heap::GCCallbackTuple::operator=(
-    const Heap::GCCallbackTuple& other) = default;
+    const Heap::GCCallbackTuple& other) V8_NOEXCEPT = default;
 
 struct Heap::StrongRootsList {
   FullObjectSlot start;
diff --git a/src/heap/spaces.cc b/src/heap/spaces.cc
index fd3032c952..d420e62c2a 100644
--- a/src/heap/spaces.cc
+++ b/src/heap/spaces.cc
@@ -2215,9 +2215,8 @@ LocalAllocationBuffer::LocalAllocationBuffer(
   *this = other;
 }
 
-
 LocalAllocationBuffer& LocalAllocationBuffer::operator=(
-    const LocalAllocationBuffer& other) {
+    const LocalAllocationBuffer& other) V8_NOEXCEPT {
   Close();
   heap_ = other.heap_;
   allocation_info_ = other.allocation_info_;