[PATCH] D133354: [Clang]: Diagnose deprecated copy operations also in MSVC compatibility mode

[Julius via Phabricator via cfe-commits]

ningvin created this revision.
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When running in MSVC compatibility mode, previously no deprecated copy operation warnings (enabled by `-Wdeprecated-copy`) were raised. This restriction was already in place when the deprecated copy warning was first introduced <https://reviews.llvm.org/rGd577fbbd1c9d6dab193d530fcd807efc3b3bc9ad>.

This patch removes said restriction so that deprecated copy warnings, if enabled, are also raised in MSVC compatibility mode. The reasoning here being that these warnings are still useful when running in MSVC compatibility mode and also have to be semi-explicitly enabled in the first place (using `-Wdeprecated-copy`, `-Wdeprecated` or `-Wextra`).


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D133354

Files:
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/SemaCXX/deprecated-copy-msvc.cpp


Index: clang/test/SemaCXX/deprecated-copy-msvc.cpp
===================================================================
--- /dev/null
+++ clang/test/SemaCXX/deprecated-copy-msvc.cpp
@@ -0,0 +1,25 @@
+// RUN: %clang_cc1 %s -std=c++11 %s -Wdeprecated-copy -verify -fms-compatibility
+
+struct A {
+  A& operator=(const A&) = default; // expected-warning {{definition of implicit copy constructor for 'A' is deprecated because it has a user-declared copy assignment operator}}
+};
+
+struct B {
+  B& operator=(const B&) = delete; // expected-warning {{definition of implicit copy constructor for 'B' is deprecated because it has a user-declared copy assignment operator}}
+};
+
+void test() {
+  A a1;
+  A a2(a1); // expected-note {{implicit copy constructor for 'A' first required here}}
+
+  B b1;
+  B b2(b1); // expected-note {{implicit copy constructor for 'B' first required here}}
+}
+
+// PR45634
+struct S {
+  int i;
+  S& operator=(const S&) = delete; // expected-warning {{definition of implicit copy constructor for 'S' is deprecated because it has a user-declared copy assignment operator}}
+};
+
+S test(const S &s) { return S(s); } // expected-note {{implicit copy constructor for 'S' first required here}}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -14429,13 +14429,10 @@
   CXXRecordDecl *RD = CopyOp->getParent();
   CXXMethodDecl *UserDeclaredOperation = nullptr;
 
-  // In Microsoft mode, assignment operations don't affect constructors and
-  // vice versa.
   if (RD->hasUserDeclaredDestructor()) {
     UserDeclaredOperation = RD->getDestructor();
   } else if (!isa<CXXConstructorDecl>(CopyOp) &&
-             RD->hasUserDeclaredCopyConstructor() &&
-             !S.getLangOpts().MSVCCompat) {
+             RD->hasUserDeclaredCopyConstructor()) {
     // Find any user-declared copy constructor.
     for (auto *I : RD->ctors()) {
       if (I->isCopyConstructor()) {
@@ -14445,8 +14442,7 @@
     }
     assert(UserDeclaredOperation);
   } else if (isa<CXXConstructorDecl>(CopyOp) &&
-             RD->hasUserDeclaredCopyAssignment() &&
-             !S.getLangOpts().MSVCCompat) {
+             RD->hasUserDeclaredCopyAssignment()) {
     // Find any user-declared move assignment operator.
     for (auto *I : RD->methods()) {
       if (I->isCopyAssignmentOperator()) {


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