From 7a980a9ba952bac42d1ec86c09cbeb11fd3a0b88 Mon Sep 17 00:00:00 2001
From: zhangziyao <zhangziyao8@huawei.com>
Date: Tue, 26 Aug 2025 14:39:32 +0800
Subject: [PATCH] [borrow] change the check order and fix the bug of unexpected
 diagnostic message

---
 clang/lib/Sema/SemaExpr.cpp                   | 19 ++++++++-----------
 .../borrow_call_arg/borrow_call_arg.cbs       | 16 ++++++++++++++++
 2 files changed, 24 insertions(+), 11 deletions(-)
 create mode 100644 clang/test/BSC/Negative/Ownership/Borrow/borrow_call_arg/borrow_call_arg.cbs

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index 08b7853f06e8..ddc38107a9ea 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -10462,10 +10462,16 @@ Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &CallerRHS,
     if (!IsSafeConversion(LHSType, RHS.get())) {
       return IncompatibleBSCSafeZone;
     }
-    if (RHS.get()->getType().getCanonicalType().isOwnedQualified() || LHSType.getCanonicalType().isOwnedQualified()) {
+    QualType LHSCanType = LHSType.getCanonicalType();
+    QualType RHSCanType = RHS.get()->getType().getCanonicalType();
+    if (RHSCanType.isOwnedQualified() || LHSCanType.isOwnedQualified()) {
       if (!CheckOwnedQualTypeAssignment(LHSType, RHS.get()))
         return IncompatibleOwnedPointer;
     }
+    if (RHSCanType.isBorrowQualified() || LHSCanType.isBorrowQualified()) {
+      if (!CheckBorrowQualTypeAssignment(LHSType, RHS.get()))
+        return IncompatibleBorrowPointer;
+    }
     if (const auto *LHSPtrType = LHSType->getAs<PointerType>()) {
       if (const auto *RHSPtrType = RHS.get()->getType()->getAs<PointerType>()) {
         if (LHSPtrType->hasOwnedFields() || RHSPtrType->hasOwnedFields()) {
@@ -10473,18 +10479,9 @@ Sema::CheckSingleAssignmentConstraints(QualType LHSType, ExprResult &CallerRHS,
             return IncompatibleOwnedPointer;
           }
         }
-      }
-    }
-
-    if (RHS.get()->getType().getCanonicalType().isBorrowQualified() || LHSType.getCanonicalType().isBorrowQualified()) {
-      if (!CheckBorrowQualTypeAssignment(LHSType, RHS.get()))
-        return IncompatibleOwnedPointer;
-    }
-    if (const auto *LHSPtrType = LHSType->getAs<PointerType>()) {
-      if (const auto *RHSPtrType = RHS.get()->getType()->getAs<PointerType>()) {
         if (LHSPtrType->hasBorrowFields() || RHSPtrType->hasBorrowFields()) {
           if (!CheckBorrowQualTypeAssignment(LHSType, RHS.get())) {
-            return IncompatibleOwnedPointer;
+            return IncompatibleBorrowPointer;
           }
         }
       }
diff --git a/clang/test/BSC/Negative/Ownership/Borrow/borrow_call_arg/borrow_call_arg.cbs b/clang/test/BSC/Negative/Ownership/Borrow/borrow_call_arg/borrow_call_arg.cbs
new file mode 100644
index 000000000000..2c3e0f1f4dda
--- /dev/null
+++ b/clang/test/BSC/Negative/Ownership/Borrow/borrow_call_arg/borrow_call_arg.cbs
@@ -0,0 +1,16 @@
+// RUN: %clang_cc1 -verify %s
+
+owned struct Rc<T> {
+};
+
+owned struct Weak<T> {
+};
+
+Weak<T> Weak<T>::new(const Rc<T> *borrow rc);
+
+owned struct S { 
+};
+
+void test(Rc<S> rc) {
+    Weak<int> wk1 = Weak<int>::new(&const rc); // expected-error {{incompatible borrow types, cannot cast 'const owned Rc<owned struct S> *borrow' to 'const owned Rc<int> *borrow'}}
+}
-- 
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