unneeded-cast: Revamp this check a bit

Now warns of unneeded qobject-casts and static_casts too.
Like casting to itself, or casting to base class.

2 files changed, 51 insertions, 2 deletions

diff --git a/tests/unneeded-cast/main.cpp b/tests/unneeded-cast/main.cpp
index c58c32ac..808e1a87 100644
--- a/tests/unneeded-cast/main.cpp
+++ b/tests/unneeded-cast/main.cpp
@@ -41,10 +41,57 @@ void test()
 
 class MyObj : public QObject
 {
+    Q_OBJECT
 public:
 };
 
 void testQObjectCast(QObject *o)
 {
     dynamic_cast<MyObj*>(o); // Warn
+    qobject_cast<QObject*>(o); // Warn
+    MyObj myobj;
+    qobject_cast<QObject*>(&myobj); // Warn
+    qobject_cast<MyObj*>(o); // OK
 }
+
+class FwdDeclared;
+
+class MyObj2 : public QObject
+{
+public:
+    Q_DECLARE_PUBLIC(QObject) // OK, in macro
+    MyObj2 *q_ptr;
+};
+
+struct Base2 {};
+class Base1 : public QObject {};
+
+class Derived : public Base1, public Base2
+{
+public:
+    void test()
+    {
+        static_cast<Base1*>(this); // OK
+        static_cast<Base2*>(this); // OK
+    }
+};
+
+void test2()
+{
+    static_cast<MyObj*>(nullptr); // OK
+    static_cast<MyObj*>(0); // OK
+
+    MyObj *o1;
+    MyObj2 *o2;
+    true ? static_cast<QObject*>(o1)  : static_cast<QObject*>(o2); // Ok
+}
+
+class MyObj4 : public QObject
+{
+    Q_OBJECT
+public:
+    void test()
+    {
+        qobject_cast<MyObj4*>(sender()); // OK
+    }
+};
diff --git a/tests/unneeded-cast/main.cpp.expected b/tests/unneeded-cast/main.cpp.expected
index bcaee9ca..448e714c 100644
--- a/tests/unneeded-cast/main.cpp.expected
+++ b/tests/unneeded-cast/main.cpp.expected
@@ -4,10 +4,12 @@ unneeded-cast/main.cpp:33:5: warning: Casting to itself [-Wclazy-unneeded-cast]
     dynamic_cast<A*>(a); // warning: Casting to itself
 unneeded-cast/main.cpp:35:5: warning: Casting to itself [-Wclazy-unneeded-cast]
     dynamic_cast<B*>(b); // warning: Casting to itself
-unneeded-cast/main.cpp:36:5: warning: Casting to itself [-Wclazy-unneeded-cast]
+unneeded-cast/main.cpp:36:5: warning: explicitly casting to base is unnecessary [-Wclazy-unneeded-cast]
     static_cast<A*>(b); // warning: Casting to base
 unneeded-cast/main.cpp:37:5: warning: Casting to itself [-Wclazy-unneeded-cast]
     static_cast<A*>(a); // warning: Casting to itself
 unneeded-cast/main.cpp:39:5: warning: Casting to itself [-Wclazy-unneeded-cast]
     static_cast<B*>(b); // warning: Casting to itself
-unneeded-cast/main.cpp:49:5: warning: Use qobject_cast rather than dynamic_cast [-Wclazy-unneeded-cast]
+unneeded-cast/main.cpp:50:5: warning: Use qobject_cast rather than dynamic_cast [-Wclazy-unneeded-cast]
+unneeded-cast/main.cpp:51:5: warning: Casting to itself [-Wclazy-unneeded-cast]
+unneeded-cast/main.cpp:53:5: warning: explicitly casting to base is unnecessary [-Wclazy-unneeded-cast]