From 1cf721fe2a9fad8d1420205bb7b4088237c822fd Mon Sep 17 00:00:00 2001
From: Tamas Toth <tamas.toth@h-lab.eu>
Date: Thu, 19 Jun 2025 13:19:49 +0200
Subject: [PATCH] Fix lambda type inference

Issue: https://gitee.com/openharmony/arkcompiler_ets_frontend/issues/ICGG85
Fixes #26798 internal issue

Change-Id: Ic702ad7fa27a7365a842cad05ef44a7264adb6b0
Signed-off-by: Tamas Toth <tamas.toth@h-lab.eu>
---
 ets2panda/checker/ets/function.cpp            | 30 +++++++++++--------
 .../ets/rest_param_lambda_type_interface.ets  | 18 +++++++++++
 ets2panda/util/diagnostic/semantic.yaml       |  8 +++--
 3 files changed, 42 insertions(+), 14 deletions(-)
 create mode 100644 ets2panda/test/ast/parser/ets/rest_param_lambda_type_interface.ets

diff --git a/ets2panda/checker/ets/function.cpp b/ets2panda/checker/ets/function.cpp
index d2423c24ca..10b3334d26 100644
--- a/ets2panda/checker/ets/function.cpp
+++ b/ets2panda/checker/ets/function.cpp
@@ -1611,21 +1611,27 @@ SignatureInfo *ETSChecker::ComposeSignatureInfo(ir::TSTypeParameterDeclaration *
         }
     }
 
-    if (!params.empty()) {
-        if (auto param = params.back()->AsETSParameterExpression(); param->IsRestParameter()) {
-            if (param->TypeAnnotation() == nullptr) {  // #23134
-                ES2PANDA_ASSERT(IsAnyError());
-                return nullptr;
-            }
-            auto restParamType = param->RestParameter()->TypeAnnotation()->GetType(this);
-            if (!restParamType->IsETSTupleType() && !restParamType->IsETSArrayType() &&
-                !restParamType->IsETSResizableArrayType()) {
-                LogError(diagnostic::ONLY_ARRAY_OR_TUPLE_FOR_REST, {}, param->Start());
+    if (params.empty()) {
+        return signatureInfo;
+    }
+
+    if (auto param = params.back()->AsETSParameterExpression(); param->IsRestParameter()) {
+        if (param->TypeAnnotation() == nullptr) {  // #23134
+            if (param->RestParameter() != nullptr) {
+                LogError(diagnostic::REST_PARAM_MUST_HAVE_TYPE_ANNOTATION, {param->Name()}, param->Start());
                 return nullptr;
             }
-            signatureInfo->restVar = SetupSignatureParameter(param, param->TypeAnnotation()->GetType(this));
-            ES2PANDA_ASSERT(signatureInfo->restVar != nullptr);
+            ES2PANDA_ASSERT(IsAnyError());
+            return nullptr;
+        }
+        auto restParamType = param->RestParameter()->TypeAnnotation()->GetType(this);
+        if (!restParamType->IsETSTupleType() && !restParamType->IsETSArrayType() &&
+            !restParamType->IsETSResizableArrayType()) {
+            LogError(diagnostic::ONLY_ARRAY_OR_TUPLE_FOR_REST, {}, param->Start());
+            return nullptr;
         }
+        signatureInfo->restVar = SetupSignatureParameter(param, param->TypeAnnotation()->GetType(this));
+        ES2PANDA_ASSERT(signatureInfo->restVar != nullptr);
     }
 
     return signatureInfo;
diff --git a/ets2panda/test/ast/parser/ets/rest_param_lambda_type_interface.ets b/ets2panda/test/ast/parser/ets/rest_param_lambda_type_interface.ets
new file mode 100644
index 0000000000..11c6c291b3
--- /dev/null
+++ b/ets2panda/test/ast/parser/ets/rest_param_lambda_type_interface.ets
@@ -0,0 +1,18 @@
+/*
+* 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 low 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.
+*/
+
+(...arg) => 102;
+
+/* @@? 16:2 Error TypeError: Rest parameter 'arg' must have an explicit type annotation. */
diff --git a/ets2panda/util/diagnostic/semantic.yaml b/ets2panda/util/diagnostic/semantic.yaml
index db1355f996..e4464ee0d4 100644
--- a/ets2panda/util/diagnostic/semantic.yaml
+++ b/ets2panda/util/diagnostic/semantic.yaml
@@ -1557,5 +1557,9 @@ semantic:
   message: "overload declaration cannot contain abstract methods."
   
 - name: INVALID_RECORD_PROPERTY
-  id: 383
-  message: "Invalid record property"
\ No newline at end of file
+  id: 393
+  message: "Invalid record property"
+
+- name: REST_PARAM_MUST_HAVE_TYPE_ANNOTATION
+  id: 394
+  message: "Rest parameter '{}' must have an explicit type annotation."
-- 
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