[PATCH] D151200: [Clang][C++20] Error out if parameter types of a defaulted comparion operator are not all the same.

[Jens Massberg via Phabricator via cfe-commits]

massberg created this revision.
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This fixes #62880


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D151200

Files:
  clang/lib/Sema/SemaDeclCXX.cpp
  clang/test/CXX/class/class.compare/class.compare.default/p1.cpp


Index: clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
===================================================================
--- clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
+++ clang/test/CXX/class/class.compare/class.compare.default/p1.cpp
@@ -27,6 +27,14 @@
     bool operator==(const A&) const = default; // expected-error {{comparison operator template cannot be defaulted}}
 };
 
+template<class C> struct D {
+  C i;
+  friend bool operator==(const D&, D) = default; // expected-error {{must have the same type}}
+  friend bool operator>(D, const D&) = default; // expected-error {{must have the same type}}
+  friend bool operator<(const D&, const D&) = default;
+  friend bool operator<=(D, D) = default;
+};
+
 template<typename T> struct Dependent {
   using U = typename T::type;
   bool operator==(U) const = default; // expected-error {{found 'U'}}
Index: clang/lib/Sema/SemaDeclCXX.cpp
===================================================================
--- clang/lib/Sema/SemaDeclCXX.cpp
+++ clang/lib/Sema/SemaDeclCXX.cpp
@@ -8626,8 +8626,7 @@
   const ParmVarDecl *KnownParm = nullptr;
   for (const ParmVarDecl *Param : FD->parameters()) {
     QualType ParmTy = Param->getType();
-    if (ParmTy->isDependentType())
-      continue;
+
     if (!KnownParm) {
       auto CTy = ParmTy;
       // Is it `T const &`?
@@ -8656,6 +8655,8 @@
       if (Ok) {
         KnownParm = Param;
       } else {
+        if (ParmTy->isDependentType())
+          continue;
         // Don't diagnose an implicit 'operator=='; we will have diagnosed the
         // corresponding defaulted 'operator<=>' already.
         if (!FD->isImplicit()) {
@@ -8675,7 +8676,8 @@
         }
         return true;
       }
-    } else if (!Context.hasSameType(KnownParm->getType(), ParmTy)) {
+    }
+    if (KnownParm && !Context.hasSameType(KnownParm->getType(), ParmTy)) {
       Diag(FD->getLocation(), diag::err_defaulted_comparison_param_mismatch)
           << int(DCK) << KnownParm->getType() << KnownParm->getSourceRange()
           << ParmTy << Param->getSourceRange();


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