diff --git a/ets2panda/checker/ets/function.cpp b/ets2panda/checker/ets/function.cpp
index 036af5331d2ad7d343b0a64d21cb21419efc16dc..9795e917cfa4cbb40ac481f8bdeefb012dcd22ad 100644
--- a/ets2panda/checker/ets/function.cpp
+++ b/ets2panda/checker/ets/function.cpp
@@ -2050,26 +2050,23 @@ bool ETSChecker::CmpAssemblerTypesWithRank(Signature const *const sig1, Signatur
 
 bool ETSChecker::HasSameAssemblySignature(Signature const *const sig1, Signature const *const sig2) noexcept
 {
-    if (sig1->ArgCount() != sig2->ArgCount()) {
+    if (sig1->FullParamCount() != sig2->FullParamCount()) {
         return false;
     }
 
-    if (!CmpAssemblerTypesWithRank(sig1, sig2)) {
-        return false;
-    }
-    auto *rv1 = sig1->RestVar();
-    auto *rv2 = sig2->RestVar();
-    if (rv1 == nullptr && rv2 == nullptr) {
-        return true;
-    }
-    if (rv1 == nullptr || rv2 == nullptr) {  // exactly one of them is null
-        return false;
+    auto sig1AllParamVector = sig1->FullParams();
+    auto sig2AllParamVector = sig2->FullParams();
+
+    for (size_t ix = 0U; ix < sig1AllParamVector.size(); ++ix) {
+        std::stringstream s1;
+        std::stringstream s2;
+        sig1AllParamVector[ix]->TsType()->ToAssemblerTypeWithRank(s1);
+        sig2AllParamVector[ix]->TsType()->ToAssemblerTypeWithRank(s2);
+        if (s1.str() != s2.str()) {
+            return false;
+        }
     }
-    std::stringstream s1;
-    std::stringstream s2;
-    rv1->TsType()->ToAssemblerTypeWithRank(s1);
-    rv2->TsType()->ToAssemblerTypeWithRank(s2);
-    return s1.str() == s2.str();
+    return true;
 }
 
 bool ETSChecker::HasSameAssemblySignatures(ETSFunctionType const *const func1,
diff --git a/ets2panda/checker/types/signature.h b/ets2panda/checker/types/signature.h
index 2a4f8ec06d417aed65fdc416c2ac9a38ee6fd543..11b478c12cea6712eb7d00e7873993eecd72ef5a 100644
--- a/ets2panda/checker/types/signature.h
+++ b/ets2panda/checker/types/signature.h
@@ -166,6 +166,21 @@ public:
         return signatureInfo_->params.size();
     }
 
+    [[nodiscard]] size_t FullParamCount() const
+    {
+        return signatureInfo_->restVar == nullptr ? signatureInfo_->params.size() : signatureInfo_->params.size() + 1;
+    }
+
+    [[nodiscard]] std::vector<varbinder::LocalVariable *> FullParams() const
+    {
+        std::vector<varbinder::LocalVariable *> allParamVector(signatureInfo_->params.begin(),
+                                                               signatureInfo_->params.end());
+        if (signatureInfo_->restVar != nullptr) {
+            allParamVector.push_back(signatureInfo_->restVar);
+        }
+        return allParamVector;
+    }
+
     void SetReturnType(Type *type) noexcept
     {
         returnType_ = type;
diff --git a/ets2panda/test/ast/compiler/ets/rest_param_has_same_assembly_test.ets b/ets2panda/test/ast/compiler/ets/rest_param_has_same_assembly_test.ets
new file mode 100644
index 0000000000000000000000000000000000000000..54f00f6bb86a650dbc8c6c9a1e3da04b56ae08e9
--- /dev/null
+++ b/ets2panda/test/ast/compiler/ets/rest_param_has_same_assembly_test.ets
@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2025 Huawei Device Co., Ltd.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+class A {
+    m(a: Error, b: Object[]): int { return 1 }
+    /* @@ label */m(a: Error, ...b: Object[]): int { return 2 }
+}
+
+class B {
+    m(a: Error, ...b: Object[]): int { return 2 }
+    /* @@ label1 */m(a: Error, b: Object[]): int { return 1 }
+}
+
+class C {
+    m(a: Error, ...b: Object[]): int { return 1 }
+    /* @@ label2 */m(a: Error, b?: Object[]): int { return 2 }
+}
+
+class D {
+    m(a: Error, b: Object[]): int { return 1 }
+    /* @@ label3 */m(a: Error, b?: Object[]): int { return 2 }
+}
+/* @@@ label Error TypeError: Function m with this assembly signature already declared.  */
+/* @@@ label1 Error TypeError: Function m with this assembly signature already declared.  */
+/* @@@ label2 Error TypeError: Function m with this assembly signature already declared.  */
+/* @@@ label3 Error TypeError: Function m with this assembly signature already declared.  */
\ No newline at end of file
diff --git a/ets2panda/test/ast/parser/ets/FixedArray/MultipleParserErrors.ets b/ets2panda/test/ast/parser/ets/FixedArray/MultipleParserErrors.ets
index 6db1b894cc10500bbd017da658a4a6b5d9b4544a..0ffeab8bc1b93bf702a9d77d15842797fc9bd87b 100644
--- a/ets2panda/test/ast/parser/ets/FixedArray/MultipleParserErrors.ets
+++ b/ets2panda/test/ast/parser/ets/FixedArray/MultipleParserErrors.ets
@@ -205,6 +205,7 @@ function main(): void {
 /* @@? 52:12 Error TypeError: Unresolved reference q */
 /* @@? 52:12 Error TypeError: All return statements in the function should be empty or have a value. */
 /* @@? 52:23 Error TypeError: Unresolved reference p */
+/* @@? 55:1 Error TypeError: Function foo with this assembly signature already declared. */
 /* @@? 55:26 Error SyntaxError: Rest parameter should be either array or tuple type. */
 /* @@? 59:23 Error SyntaxError: Rest parameter should be either array or tuple type. */
 /* @@? 63:26 Error SyntaxError: Parameter declaration should have an explicit type annotation. */
@@ -284,4 +285,4 @@ function main(): void {
 /* @@? 165:5 Error TypeError: This expression is not callable. */
 /* @@? 166:5 Error TypeError: Expected 1 arguments, got 0. */
 /* @@? 166:5 Error TypeError: No matching call signature */
-/* @@? 288:1 Error SyntaxError: Expected '}', got 'eos'. */
+/* @@? 289:1 Error SyntaxError: Expected '}', got 'eos'. */
diff --git a/ets2panda/test/ast/parser/ets/MultipleParserErrors.ets b/ets2panda/test/ast/parser/ets/MultipleParserErrors.ets
index d938d892ff459d4fe1fe567faecb0eb969151f06..135df246b00f74cd180a49cdfc3958d5f05d3250 100644
--- a/ets2panda/test/ast/parser/ets/MultipleParserErrors.ets
+++ b/ets2panda/test/ast/parser/ets/MultipleParserErrors.ets
@@ -203,6 +203,7 @@ function main(): void {
 /* @@? 52:12 Error TypeError: Unresolved reference q */
 /* @@? 52:12 Error TypeError: All return statements in the function should be empty or have a value. */
 /* @@? 52:23 Error TypeError: Unresolved reference p */
+/* @@? 55:1 Error TypeError: Function foo with this assembly signature already declared. */
 /* @@? 55:26 Error SyntaxError: Rest parameter should be either array or tuple type. */
 /* @@? 59:23 Error SyntaxError: Rest parameter should be either array or tuple type. */
 /* @@? 63:26 Error SyntaxError: Parameter declaration should have an explicit type annotation. */
@@ -282,4 +283,4 @@ function main(): void {
 /* @@? 165:5 Error TypeError: This expression is not callable. */
 /* @@? 166:5 Error TypeError: Expected 1 arguments, got 0. */
 /* @@? 166:5 Error TypeError: No matching call signature */
-/* @@? 286:1 Error SyntaxError: Expected '}', got 'eos'. */
+/* @@? 287:1 Error SyntaxError: Expected '}', got 'eos'. */