fix: discard on command_encoder_drop on all backends

Author: ErichDonGubler

wgpu-core/src/command/mod.rs

@@ -75,7 +75,7 @@ impl<A: HalApi> CommandEncoder<A> {
         Ok(())
     }
 
-    fn discard(&mut self) {
+    pub(crate) fn discard(&mut self) {
         if self.is_open {
             self.is_open = false;
             unsafe { self.raw.discard_encoding() };
@@ -112,7 +112,7 @@ pub(crate) struct DestroyedBufferError(pub id::BufferId);
 pub(crate) struct DestroyedTextureError(pub id::TextureId);
 
 pub struct CommandBufferMutable<A: HalApi> {
-    encoder: CommandEncoder<A>,
+    pub(crate) encoder: CommandEncoder<A>,
     status: CommandEncoderStatus,
     pub(crate) trackers: Tracker<A>,
     buffer_memory_init_actions: Vec<BufferInitTrackerAction<A>>,

wgpu-core/src/device/global.rs

@@ -1377,6 +1377,7 @@ impl Global {
             .command_buffers
             .unregister(command_encoder_id.transmute())
         {
+            cmd_buf.data.lock().as_mut().unwrap().encoder.discard();
             cmd_buf
                 .device
                 .untrack(&cmd_buf.data.lock().as_ref().unwrap().trackers);