[clang] [Clang] Implement C++26’s P2893R3 ‘Variadic friends’ (PR #101448)

[via cfe-commits]

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@@ -862,13 +881,21 @@ void DeclPrinter::VisitFunctionDecl(FunctionDecl *D) {
   }
 }
 
-void DeclPrinter::VisitFriendDecl(FriendDecl *D) {
+void DeclPrinter::VisitFriendDecl(FriendDecl *D, bool FirstInGroup) {
   if (TypeSourceInfo *TSI = D->getFriendType()) {
     unsigned NumTPLists = D->getFriendTypeNumTemplateParameterLists();
     for (unsigned i = 0; i < NumTPLists; ++i)
       printTemplateParameters(D->getFriendTypeTemplateParameterList(i));
-    Out << "friend ";
-    Out << " " << TSI->getType().getAsString(Policy);
+
+    // Hack to print friend declarations declared as a group, e.g.
+    // 'friend int, long;', instead of printing them as two separate
+    // FriendDecls, which they are in the AST.
+    if (FirstInGroup)
+      Out << "friend ";
+    else
+      Out << ", ";
+
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cor3ntin wrote:

Can we use ListSeparator here?

https://github.com/llvm/llvm-project/pull/101448