From 319a5ccd86be2c3030e948964217f178f94ce020 Mon Sep 17 00:00:00 2001
From: Christian Kandeler <christian.kandeler@qt.io>
Date: Thu, 12 Dec 2024 16:58:25 +0100
Subject: [PATCH] CppEditor: Fix InsertVirtualMethods quickfix

... for base classes pulled in via using declarations.
This is probably just a hack, like everything connected to the weird
ClassOrNamespace class.

Fixes: QTCREATORBUG-32162
Change-Id: Id7fbcf569fca231284ad0026cc040b16ac04960c
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
---
 .../quickfixes/cppinsertvirtualmethods.cpp    | 27 +++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/plugins/cppeditor/quickfixes/cppinsertvirtualmethods.cpp b/src/plugins/cppeditor/quickfixes/cppinsertvirtualmethods.cpp
index 25324bcd46d..005c3625928 100644
--- a/src/plugins/cppeditor/quickfixes/cppinsertvirtualmethods.cpp
+++ b/src/plugins/cppeditor/quickfixes/cppinsertvirtualmethods.cpp
@@ -559,9 +559,17 @@ public:
         while (!baseClassQueue.isEmpty()) {
             ClassOrNamespace *clazz = baseClassQueue.dequeue();
             visitedBaseClasses.insert(clazz);
-            const QList<ClassOrNamespace *> bases = clazz->usings();
-            for (const ClassOrNamespace *baseClass : bases) {
+            QList<ClassOrNamespace *> bases = clazz->usings();
+            while (!bases.isEmpty()) {
+                const ClassOrNamespace *baseClass = bases.takeFirst();
                 const QList<Symbol *> symbols = baseClass->symbols();
+
+                // See QTCREATORBUG-32162.
+                if (symbols.isEmpty() && baseClass->usings().size() == 1) {
+                    bases.prepend(baseClass->usings().first());
+                    continue;
+                }
+
                 for (Symbol *symbol : symbols) {
                     Class *base = symbol->asClass();
                     if (base
@@ -1852,6 +1860,21 @@ void InsertVirtualMethodsTest::test_data()
         "};\n\n"
         "struct Derived2 : Derived1\n"
         "};\n");
+
+    QTest::newRow("base class via using")
+        << InsertVirtualMethodsDialog::ModeOnlyDeclarations << false << true
+        << _(R"cpp(
+                  namespace A { struct Base { virtual void foo() = 0; }; } // namespace A
+                  using A::Base;
+                  struct @Derived : Base {};)cpp")
+        << _(R"cpp(
+                  namespace A { struct Base { virtual void foo() = 0; }; } // namespace A
+                  using A::Base;
+                  struct @Derived : Base {
+                      // Base interface
+                  public:
+                      void foo() override;
+                  };)cpp");
 }
 
 void InsertVirtualMethodsTest::test()