[clang] Show error if defaulted comparions operator function is volatile or has ref-qualifier &&.

This patch implemed the change proposed in [P2002R1] to 11.11.1 [class.compare.default] paragraph 1.

A defaulted compariosn operator function must be non-volatile and must either have no ref-qualifier or the ref-qualifier &.

Differential Revision: https://reviews.llvm.org/D148924

1 files changed, 24 insertions, 2 deletions

diff --git a/clang/lib/Sema/SemaDeclCXX.cpp b/clang/lib/Sema/SemaDeclCXX.cpp
index 3169b38..9b3bcc2 100644
--- a/clang/lib/Sema/SemaDeclCXX.cpp
+++ b/clang/lib/Sema/SemaDeclCXX.cpp
@@ -8582,8 +8582,8 @@ bool Sema::CheckExplicitlyDefaultedComparison(Scope *S, FunctionDecl *FD,
   // C++2a [class.compare.default]p1:
   //   A defaulted comparison operator function for some class C shall be a
   //   non-template function declared in the member-specification of C that is
-  //    -- a non-static const member of C having one parameter of type
-  //       const C&, or
+  //    -- a non-static const non-volatile member of C having one parameter of
+  //       type const C& and either no ref-qualifier or the ref-qualifier &, or
   //    -- a friend of C having two parameters of type const C& or two
   //       parameters of type C.
 
@@ -8593,6 +8593,17 @@ bool Sema::CheckExplicitlyDefaultedComparison(Scope *S, FunctionDecl *FD,
     auto *MD = cast<CXXMethodDecl>(FD);
     assert(!MD->isStatic() && "comparison function cannot be a static member");
 
+    if (MD->getRefQualifier() == RQ_RValue) {
+      Diag(MD->getLocation(), diag::err_ref_qualifier_comparison_operator);
+
+      // Remove the ref qualifier to recover.
+      const auto *FPT = MD->getType()->castAs<FunctionProtoType>();
+      FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
+      EPI.RefQualifier = RQ_None;
+      MD->setType(Context.getFunctionType(FPT->getReturnType(),
+                                          FPT->getParamTypes(), EPI));
+    }
+
     // If we're out-of-class, this is the class we're comparing.
     if (!RD)
       RD = MD->getParent();
@@ -8615,6 +8626,17 @@ bool Sema::CheckExplicitlyDefaultedComparison(Scope *S, FunctionDecl *FD,
       MD->setType(Context.getFunctionType(FPT->getReturnType(),
                                           FPT->getParamTypes(), EPI));
     }
+
+    if (MD->isVolatile()) {
+      Diag(MD->getLocation(), diag::err_volatile_comparison_operator);
+
+      // Remove the 'volatile' from the type to recover.
+      const auto *FPT = MD->getType()->castAs<FunctionProtoType>();
+      FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
+      EPI.TypeQuals.removeVolatile();
+      MD->setType(Context.getFunctionType(FPT->getReturnType(),
+                                          FPT->getParamTypes(), EPI));
+    }
   }
 
   if (FD->getNumParams() != (IsMethod ? 1 : 2)) {