diff --git a/ets2panda/checker/ETSchecker.cpp b/ets2panda/checker/ETSchecker.cpp
index d5290ab601f9156a87ba0d3224b95f8fc1a351b1..0c802616908f7e074d431d4c55bf0b280bfe0336 100644
--- a/ets2panda/checker/ETSchecker.cpp
+++ b/ets2panda/checker/ETSchecker.cpp
@@ -76,8 +76,11 @@ void ETSChecker::ReputCheckerData()
         auto &globalArraySigs = eChecker->globalArraySignatures_;
         globalArraySignatures_.insert(globalArraySigs.cbegin(), globalArraySigs.cend());
 
-        auto &apparentTypes = eChecker->apparentTypes_;
-        apparentTypes_.insert(apparentTypes.cbegin(), apparentTypes.cend());
+        {
+            os::memory::LockHolder lock(apparentTypesLock_);
+            auto &apparentTypes = eChecker->apparentTypes_;
+            apparentTypes_.insert(apparentTypes.cbegin(), apparentTypes.cend());
+        }
 
         auto &objectInstantiationMap = eChecker->objectInstantiationMap_;
         for (auto &[key, value] : objectInstantiationMap) {
diff --git a/ets2panda/checker/ETSchecker.h b/ets2panda/checker/ETSchecker.h
index d27cf96faa3f0628ccc6b076f3179333d1f937c9..e43d5783f101b42633baf0c531c19b79af5ecbf7 100644
--- a/ets2panda/checker/ETSchecker.h
+++ b/ets2panda/checker/ETSchecker.h
@@ -28,6 +28,7 @@
 #include "ir/visitor/AstVisitor.h"
 #include "types/type.h"
 #include "util/helpers.h"
+#include "os/mutex.h"
 
 namespace ark::es2panda::varbinder {
 class VarBinder;
@@ -941,6 +942,7 @@ public:
 
     void ClearApparentTypes() noexcept
     {
+        os::memory::LockHolder lock(apparentTypesLock_);
         apparentTypes_.clear();
     }
 
@@ -962,7 +964,7 @@ public:
         }
         dynamicLambdaSignatureCache_.clear();
         functionalInterfaceCache_.clear();
-        apparentTypes_.clear();
+        ClearApparentTypes();
         for (auto &dynamicCallNamesMap : dynamicCallNames_) {
             dynamicCallNamesMap.clear();
         }
@@ -1117,6 +1119,7 @@ private:
     DynamicLambdaObjectSignatureMap dynamicLambdaSignatureCache_;
     FunctionalInterfaceMap functionalInterfaceCache_;
     TypeMapping apparentTypes_;
+    ark::os::memory::RecursiveMutex apparentTypesLock_;
     std::array<DynamicCallNamesMap, 2U> dynamicCallNames_;
     std::recursive_mutex mtx_;
     evaluate::ScopedDebugInfoPlugin *debugInfoPlugin_ {nullptr};
diff --git a/ets2panda/checker/ets/object.cpp b/ets2panda/checker/ets/object.cpp
index e88dc37f377a4878c695a4bb06ad6d332d445cbb..2205d5435444078a941b39c9c197072c14bbcfcc 100644
--- a/ets2panda/checker/ets/object.cpp
+++ b/ets2panda/checker/ets/object.cpp
@@ -2615,11 +2615,10 @@ Type *ETSChecker::GetApparentType(Type *type)
 {
     auto currChecker = compiler::GetPhaseManager()->Context()->GetChecker()->AsETSChecker();
     auto &apparentTypes = currChecker->apparentTypes_;
-
+    os::memory::LockHolder lock(apparentTypesLock_);
     if (auto it = apparentTypes.find(type); LIKELY(it != apparentTypes.end())) {
         return it->second;
     }
-
     auto cached = [&apparentTypes, type](Type *res) {
         if (type != res) {
             apparentTypes.insert({type, res});
diff --git a/ets2panda/checker/types/typeRelation.h b/ets2panda/checker/types/typeRelation.h
index 33c32e789cfada5d83580cd839f5aacf80fa48e5..e77e6c93d4802f42c3f0b731d4636c34e7b8686e 100644
--- a/ets2panda/checker/types/typeRelation.h
+++ b/ets2panda/checker/types/typeRelation.h
@@ -105,6 +105,7 @@ public:
 
     const RelationEntry *Find(RelationKey key) const
     {
+        ark::os::memory::ReadLockHolder lock(rwLock_);
         auto it = cached_.find(key);
         if (it == cached_.cend()) {
             return nullptr;
@@ -114,16 +115,19 @@ public:
 
     void Insert(RelationKey key, RelationEntry entry)
     {
+        ark::os::memory::WriteLockHolder lock(rwLock_);
         cached_.insert({key, entry});
     }
 
     void Clear()
     {
+        ark::os::memory::WriteLockHolder lock(rwLock_);
         cached_.clear();
     }
 
 private:
     ArenaUnorderedMap<RelationKey, RelationEntry> cached_;
+    mutable ark::os::memory::RWLock rwLock_;
 };
 
 class TypeRelation {
diff --git a/ets2panda/compiler/lowering/phase.cpp b/ets2panda/compiler/lowering/phase.cpp
index 4dd62cd22f43e0431bce0cac6462659346fa8501..165a79f1b8e1dea8f15b6434cc7a774b95b383cd 100644
--- a/ets2panda/compiler/lowering/phase.cpp
+++ b/ets2panda/compiler/lowering/phase.cpp
@@ -202,7 +202,7 @@ std::vector<Phase *> GetJSPhaseList()
     };
 }
 
-thread_local PhaseManager *g_phaseManager {nullptr};
+PhaseManager *g_phaseManager {nullptr};
 
 PhaseManager *GetPhaseManager()
 {