[Windows] Fix use after free during window destruction (#1746)

CHANGELOG.md

@@ -6,6 +6,7 @@
 - **Breaking:** On Windows, include prefix byte in scancodes.
 - On Wayland, fix window not being resizeable when using `with_min_inner_size` in `WindowBuilder`.
 - On Unix, fix cross-compiling to wasm32 without enabling X11 or Wayland.
+- On Windows, fix use after free crash during window destruction.
 
 # 0.23.0 (2020-10-02)
 

src/platform_impl/windows/event_loop.rs

@@ -810,7 +810,10 @@ unsafe extern "system" fn public_window_callback<T: 'static>(
                 event: Destroyed,
             });
             subclass_input.event_loop_runner.remove_window(window);
+            0
+        }
 
+        winuser::WM_NCDESTROY => {
             drop(subclass_input);
             Box::from_raw(subclass_input_ptr as *mut SubclassInput<T>);
             0