diff --git a/ets2panda/checker/ets/function.cpp b/ets2panda/checker/ets/function.cpp
index d929762e4ea114d4aa323ba4dda8f3aad47c3bfb..9ac333fc1503301f6ebf66cf4a0afebe1a1b3e28 100644
--- a/ets2panda/checker/ets/function.cpp
+++ b/ets2panda/checker/ets/function.cpp
@@ -407,6 +407,19 @@ static void ClearPreferredTypeForArray(checker::ETSChecker *checker, ir::Express
     }
 }
 
+static bool CheckArrowFunctionParamIfNeeded(ETSChecker *checker, Signature *substitutedSig,
+                                            const ArenaVector<ir::Expression *> &arguments, TypeRelationFlag flags)
+{
+    if ((flags & TypeRelationFlag::NO_CHECK_TRAILING_LAMBDA) != 0 && arguments.back()->IsArrowFunctionExpression()) {
+        ir::ScriptFunction *const lambda = arguments.back()->AsArrowFunctionExpression()->Function();
+        auto targetParm = substitutedSig->GetSignatureInfo()->params.back()->Declaration()->Node();
+        if (!checker->CheckLambdaAssignable(targetParm->AsETSParameterExpression(), lambda)) {
+            return false;
+        }
+    }
+    return true;
+}
+
 // CC-OFFNXT(huge_method[C++], G.FUN.01-CPP, G.FUD.05) solid logic
 bool ETSChecker::ValidateSignatureRequiredParams(Signature *substitutedSig,
                                                  const ArenaVector<ir::Expression *> &arguments, TypeRelationFlag flags,
@@ -467,14 +480,7 @@ bool ETSChecker::ValidateSignatureRequiredParams(Signature *substitutedSig,
         }
     }
 
-    if ((flags & TypeRelationFlag::NO_CHECK_TRAILING_LAMBDA) != 0 && arguments.back()->IsArrowFunctionExpression()) {
-        ir::ScriptFunction *const lambda = arguments.back()->AsArrowFunctionExpression()->Function();
-        auto targetParm = substitutedSig->GetSignatureInfo()->params.back()->Declaration()->Node();
-        if (!CheckLambdaAssignable(targetParm->AsETSParameterExpression(), lambda)) {
-            return false;
-        }
-    }
-    return true;
+    return CheckArrowFunctionParamIfNeeded(this, substitutedSig, arguments, flags);
 }
 
 bool ETSChecker::ValidateSignatureInvocationContext(Signature *substitutedSig, ir::Expression *argument,
diff --git a/ets2panda/checker/types/ets/etsObjectType.cpp b/ets2panda/checker/types/ets/etsObjectType.cpp
index 8a02358fb9b6d9d40abcf07dddb2d9ca6d4f2da7..d63f83880c7fdfca19d113cb269132d53084a8cc 100644
--- a/ets2panda/checker/types/ets/etsObjectType.cpp
+++ b/ets2panda/checker/types/ets/etsObjectType.cpp
@@ -201,6 +201,27 @@ ETSFunctionType *ETSObjectType::CreateMethodTypeForProp(const util::StringView &
     return checker->CreateETSMethodType(name, {{}, Allocator()->Adapter()});
 }
 
+static void ReplaceArgInSig(std::multimap<size_t, Signature *> &signatureSet, Signature *sigToInsert,
+                            TypeRelation *relation)
+{
+    auto range = signatureSet.equal_range(sigToInsert->ArgCount());
+    bool replaced = false;
+    for (auto it = range.first; it != range.second; ++it) {
+        auto sigToReplace = it->second;
+
+        if (relation->IsSupertypeOf(sigToReplace->Owner(), sigToInsert->Owner()) &&
+            relation->SignatureIsSupertypeOf(sigToReplace, sigToInsert)) {
+            signatureSet.erase(it);
+            signatureSet.insert({sigToInsert->ArgCount(), sigToInsert});
+            replaced = true;
+            break;
+        }
+    }
+    if (!replaced) {
+        signatureSet.insert({sigToInsert->ArgCount(), sigToInsert});
+    }
+}
+
 // CC-OFFNXT(huge_depth) solid logic
 static void AddSignatureToSignatureSet(std::multimap<size_t, Signature *> &signatureSet,
                                        varbinder::LocalVariable *found, TypeRelation *relation,
@@ -213,22 +234,7 @@ static void AddSignatureToSignatureSet(std::multimap<size_t, Signature *> &signa
         }
 
         if (signatureSet.count(sigToInsert->ArgCount()) != 0U) {
-            auto range = signatureSet.equal_range(sigToInsert->ArgCount());
-            bool replaced = false;
-            for (auto it = range.first; it != range.second; ++it) {
-                auto sigToReplace = it->second;
-
-                if (relation->IsSupertypeOf(sigToReplace->Owner(), sigToInsert->Owner()) &&
-                    relation->SignatureIsSupertypeOf(sigToReplace, sigToInsert)) {
-                    signatureSet.erase(it);
-                    signatureSet.insert({sigToInsert->ArgCount(), sigToInsert});
-                    replaced = true;
-                    break;
-                }
-            }
-            if (!replaced) {
-                signatureSet.insert({sigToInsert->ArgCount(), sigToInsert});
-            }
+            ReplaceArgInSig(signatureSet, sigToInsert, relation);
         } else {
             signatureSet.insert({sigToInsert->ArgCount(), sigToInsert});
         }
diff --git a/ets2panda/compiler/core/compilerImpl.cpp b/ets2panda/compiler/core/compilerImpl.cpp
index 6c78c3146b070a6dc2ea47946f2a5ba98bcb7501..f569b4f25896cd3b6d1723a1f282fd76dfa7a209 100644
--- a/ets2panda/compiler/core/compilerImpl.cpp
+++ b/ets2panda/compiler/core/compilerImpl.cpp
@@ -172,6 +172,12 @@ static bool DoIsolatedDeclgenCheck(const util::Options &options, const std::stri
     return true;
 }
 
+static bool CheckIfPhaseToSkip(util::Options &options, const std::string &name)
+{
+    return options.GetSkipPhases().count(name) > 0 ||
+           (options.IsGenerateDeclEnableIsolated() && name == compiler::InsertOptionalParametersAnnotation::NAME);
+}
+
 // CC-OFFNXT(huge_method[C++], G.FUN.01-CPP, G.FUD.05) solid logic
 static bool RunVerifierAndPhases(public_lib::Context &context, parser::Program &program)
 {
@@ -184,7 +190,6 @@ static bool RunVerifierAndPhases(public_lib::Context &context, parser::Program &
         options.SetGenerateDeclEnabled(true);
     }
 
-    bool skipPhase = false;
     bool afterCheckerPhase = false;
     while (auto phase = context.phaseManager->NextPhase()) {
         const auto name = std::string {phase->Name()};
@@ -192,10 +197,7 @@ static bool RunVerifierAndPhases(public_lib::Context &context, parser::Program &
             afterCheckerPhase = true;
         }
 
-        skipPhase =
-            options.GetSkipPhases().count(name) > 0 ||
-            (options.IsGenerateDeclEnableIsolated() && name == compiler::InsertOptionalParametersAnnotation::NAME);
-        if (skipPhase) {
+        if (CheckIfPhaseToSkip(options, name)) {
             continue;
         }
 
@@ -215,6 +217,7 @@ static bool RunVerifierAndPhases(public_lib::Context &context, parser::Program &
         if (!options.IsGenerateDeclEnableIsolated()) {
             verifier.IntroduceNewInvariants(phase->Name());
         }
+
         if (verifierEachPhase || options.HasVerifierPhase(phase->Name())) {
             verifier.Verify(phase->Name());
         }
diff --git a/ets2panda/compiler/lowering/ets/unboxLowering.cpp b/ets2panda/compiler/lowering/ets/unboxLowering.cpp
index 68ee229e51f3f7956e143fde4d6161f4ad7f1a61..dcb1c53a5e2a768a10b5884c5182304ee004003f 100644
--- a/ets2panda/compiler/lowering/ets/unboxLowering.cpp
+++ b/ets2panda/compiler/lowering/ets/unboxLowering.cpp
@@ -420,6 +420,26 @@ static ir::Expression *CreateToIntrinsicCallExpression(UnboxContext *uctx, check
     return call;
 }
 
+static bool CheckIfOnTopOfUnboxing(UnboxContext *uctx, ir::Expression *expr, checker::Type *unboxedType,
+                                   checker::Type *boxedType)
+{
+    return expr->IsCallExpression() && expr->AsCallExpression()->Arguments().empty() &&
+           expr->AsCallExpression()->Callee()->IsMemberExpression() &&
+           expr->AsCallExpression()->Callee()->AsMemberExpression()->Property()->IsIdentifier() &&
+           expr->AsCallExpression()->Callee()->AsMemberExpression()->Property()->AsIdentifier()->Name() ==
+               // CC-OFFNXT(G.FMT.02) project code style
+               UnboxerMethodName(unboxedType) &&
+           uctx->checker->Relation()->IsIdenticalTo(
+               expr->AsCallExpression()->Callee()->AsMemberExpression()->Object()->TsType(), boxedType);
+}
+
+static ir::Expression *LinkUnboxingExpr(ir::Expression *expr, ir::AstNode *parent)
+{
+    auto *ret = expr->AsCallExpression()->Callee()->AsMemberExpression()->Object();
+    ret->SetParent(parent);
+    return ret;
+}
+
 // CC-OFFNXT(huge_method[C++], G.FUN.01-CPP, G.FUD.05) solid logic
 static ir::Expression *InsertBoxing(UnboxContext *uctx, ir::Expression *expr)
 {
@@ -428,17 +448,8 @@ static ir::Expression *InsertBoxing(UnboxContext *uctx, ir::Expression *expr)
     auto *parent = expr->Parent();
 
     // Avoid boxing application right on top of unboxing.
-    if (expr->IsCallExpression() && expr->AsCallExpression()->Arguments().empty() &&
-        expr->AsCallExpression()->Callee()->IsMemberExpression() &&
-        expr->AsCallExpression()->Callee()->AsMemberExpression()->Property()->IsIdentifier() &&
-        expr->AsCallExpression()->Callee()->AsMemberExpression()->Property()->AsIdentifier()->Name() ==
-            // CC-OFFNXT(G.FMT.02) project code style
-            UnboxerMethodName(unboxedType) &&
-        uctx->checker->Relation()->IsIdenticalTo(
-            expr->AsCallExpression()->Callee()->AsMemberExpression()->Object()->TsType(), boxedType)) {
-        auto *ret = expr->AsCallExpression()->Callee()->AsMemberExpression()->Object();
-        ret->SetParent(parent);
-        return ret;
+    if (CheckIfOnTopOfUnboxing(uctx, expr, unboxedType, boxedType)) {
+        return LinkUnboxingExpr(expr, parent);
     }
 
     auto *allocator = uctx->allocator;