diff --git a/ets2panda/compiler/lowering/ets/constantExpressionLowering.cpp b/ets2panda/compiler/lowering/ets/constantExpressionLowering.cpp
index 96da74bb4bfd40af081062b4814b08f8cad5c379..65cba7026ecc77a403c72ab49ed942ed4d74a1f1 100644
--- a/ets2panda/compiler/lowering/ets/constantExpressionLowering.cpp
+++ b/ets2panda/compiler/lowering/ets/constantExpressionLowering.cpp
@@ -674,7 +674,13 @@ ir::AstNode *ConstantExpressionLowering::FoldUnaryConstant(ir::UnaryExpression *
         return FoldUnaryBooleanConstant(unary);
     }
 
-    return FoldUnaryNumericConstant(unary);
+    auto lit = unary->Argument()->AsLiteral();
+    if (lit->IsNumberLiteral() || lit->IsCharLiteral()) {
+        return FoldUnaryNumericConstant(unary, context->allocator);
+    }
+
+    LogError(context, diagnostic::WRONG_OPERAND_TYPE_FOR_UNARY_EXPRESSION, {}, unary->Start());
+    return CreateErrorIdentifier(unary, context->allocator);
 }
 
 ir::AstNode *ConstantExpressionLowering::TryFoldTSAsExpressionForString(ir::TSAsExpression *expr)
@@ -792,8 +798,28 @@ ir::AstNode *ConstantExpressionLowering::UnFoldEnumMemberExpression(ir::AstNode
 
         return node;
     };
-    constantNode->TransformChildrenRecursivelyPostorder(handleUnfoldEnumMember, Name());
-    return constantNode;
+
+    util::UString result(allocator);
+    auto quasis = expr->Quasis();
+    auto expressions = expr->Expressions();
+
+    if (!quasis.empty() && !quasis[0]->Raw().Empty()) {
+        result.Append(quasis[0]->Cooked());
+    }
+
+    auto const num = expressions.size();
+    std::size_t i = 0U;
+    while (i < num) {
+        result.Append(litToString(expressions[i]->AsLiteral()));
+        if (!quasis[++i]->Raw().Empty()) {
+            result.Append(quasis[i]->Cooked());
+        }
+    }
+
+    auto *strLit = util::NodeAllocator::Alloc<ir::StringLiteral>(allocator, result.View());
+    strLit->SetParent(expr->Parent());
+    strLit->SetRange(expr->Range());
+    return strLit;
 }
 
 ir::AstNode *ConstantExpressionLowering::FindNameInEnumMember(ArenaVector<ir::AstNode *> *members,
diff --git a/ets2panda/test/ast/compiler/ets/constantExpressionLowering.ets b/ets2panda/test/ast/compiler/ets/constantExpressionLowering.ets
new file mode 100644
index 0000000000000000000000000000000000000000..fa6ab227a59a4186cdd10e47e5c3839da42e54c3
--- /dev/null
+++ b/ets2panda/test/ast/compiler/ets/constantExpressionLowering.ets
@@ -0,0 +1,27 @@
+/*
+ * 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.
+ */
+
+// 1.
+const tmpl = ``
+
+// 2.
+const flag = true
+const a = +(flag)
+const b = -(flag)
+const c = ~(flag)
+
+/* @@? 21:11 Error TypeError: Wrong operand type for unary expression */
+/* @@? 22:11 Error TypeError: Wrong operand type for unary expression */
+/* @@? 23:11 Error TypeError: Wrong operand type for unary expression */