cxx-qt-lib: remove null-pointer dereference from QStringList's upcast

Author: jnbooth

crates/cxx-qt-lib/src/core/qstringlist.rs

@@ -2,7 +2,6 @@
 // SPDX-FileContributor: Andrew Hayzen <andrew.hayzen@kdab.com>
 //
 // SPDX-License-Identifier: MIT OR Apache-2.0
-use crate::core::qstringlist::ffi::QList_QString;
 use crate::{QList, QString};
 use core::mem::MaybeUninit;
 use cxx::{type_id, ExternType};
@@ -28,21 +27,6 @@ mod ffi {
         include!("cxx-qt-lib/qstringlist.h");
         type QStringList = super::QStringList;
 
-        include!("cxx-qt/casting.h");
-
-        #[doc(hidden)]
-        #[rust_name = "upcast_qstringlist"]
-        #[cxx_name = "upcastPtr"]
-        #[namespace = "rust::cxxqt1"]
-        unsafe fn upcast(thiz: *const QStringList) -> *const QList_QString;
-
-        #[doc(hidden)]
-        #[rust_name = "downcast_qlist_qstring"]
-        #[cxx_name = "downcastPtr"]
-        #[namespace = "rust::cxxqt1"]
-        #[cfg(cxxqt_qt_version_at_least_6)]
-        unsafe fn downcast(base: *const QList_QString) -> *const QStringList;
-
         /// Returns true if the list contains the string str; otherwise returns false.
         fn contains(self: &QStringList, str: &QString, cs: CaseSensitivity) -> bool;
 
@@ -67,6 +51,19 @@ mod ffi {
         ) -> &mut QStringList;
     }
 
+    #[namespace = "rust::cxxqt1"]
+    unsafe extern "C++" {
+        include!("cxx-qt/casting.h");
+
+        #[doc(hidden)]
+        #[rust_name = "upcast_qstringlist"]
+        unsafe fn upcastPtr(thiz: *const QStringList) -> *const QList_QString;
+
+        #[doc(hidden)]
+        #[rust_name = "downcast_qlist_qstring"]
+        unsafe fn downcastPtrStatic(base: *const QList_QString) -> *const QStringList;
+    }
+
     #[namespace = "rust::cxxqtlib1"]
     unsafe extern "C++" {
         include!("cxx-qt-lib/common.h");
@@ -207,20 +204,14 @@ impl DerefMut for QStringList {
     }
 }
 
-impl Upcast<QList_QString> for QStringList {
-    unsafe fn upcast_ptr(this: *const Self) -> *const QList_QString {
+impl Upcast<QList<QString>> for QStringList {
+    unsafe fn upcast_ptr(this: *const Self) -> *const QList<QString> {
         ffi::upcast_qstringlist(this)
     }
 
-    #[cfg(cxxqt_qt_version_at_least_6)]
-    unsafe fn from_base_ptr(base: *const QList_QString) -> *const Self {
+    unsafe fn from_base_ptr(base: *const QList<QString>) -> *const Self {
         ffi::downcast_qlist_qstring(base)
     }
-
-    #[cfg(cxxqt_qt_version_major = "5")]
-    unsafe fn from_base_ptr(_base: *const QList_QString) -> *const Self {
-        std::ptr::null()
-    }
 }
 
 // Safety: