diff --git a/src/libs/utils/tasktree.cpp b/src/libs/utils/tasktree.cpp
index 55afcfdf401..2cc635e0cfa 100644
--- a/src/libs/utils/tasktree.cpp
+++ b/src/libs/utils/tasktree.cpp
@@ -20,7 +20,7 @@ TreeStorageBase::TreeStorageBase(StorageConstructor ctor, StorageDestructor dtor
 TreeStorageBase::StorageData::~StorageData()
 {
     QTC_CHECK(m_storageHash.isEmpty());
-    for (void *ptr : m_storageHash)
+    for (void *ptr : std::as_const(m_storageHash))
         m_destructor(ptr);
 }
 
@@ -47,8 +47,8 @@ void TreeStorageBase::deleteStorage(int id)
     QTC_ASSERT(m_storageData->m_constructor, return); // TODO: add isValid()?
     QTC_ASSERT(m_storageData->m_destructor, return);
     QTC_ASSERT(m_storageData->m_activeStorage == 0, return); // TODO: should be allowed?
-    const auto it = m_storageData->m_storageHash.find(id);
-    QTC_ASSERT(it != m_storageData->m_storageHash.end(), return);
+    const auto it = m_storageData->m_storageHash.constFind(id);
+    QTC_ASSERT(it != m_storageData->m_storageHash.constEnd(), return);
     m_storageData->m_destructor(it.value());
     m_storageData->m_storageHash.erase(it);
 }
diff --git a/src/libs/utils/tasktree.h b/src/libs/utils/tasktree.h
index 5a7ba5fc5e3..b89a68828d8 100644
--- a/src/libs/utils/tasktree.h
+++ b/src/libs/utils/tasktree.h
@@ -266,7 +266,7 @@ public:
                     wrapEnd(done), wrapEnd(error)}) {}
 
 private:
-    static TaskSetupHandler wrapSetup(SetupHandler handler) {
+    static TaskSetupHandler wrapSetup(const SetupHandler &handler) {
         if (!handler)
             return {};
         return [handler](TaskInterface &taskInterface) {
@@ -274,7 +274,7 @@ private:
             handler(*adapter.task());
         };
     };
-    static TaskEndHandler wrapEnd(EndHandler handler) {
+    static TaskEndHandler wrapEnd(const EndHandler &handler) {
         if (!handler)
             return {};
         return [handler](const TaskInterface &taskInterface) {