fix: Move DropGuards to the end of their parent structs.

This makes them be dropped after all other fields, which may be
necessary, since the drop guard keeps the underlying resources alive.

Author: jerzywilczek

CHANGELOG.md

@@ -90,6 +90,10 @@ SamplerDescriptor {
 
 - Align copies b/w textures and buffers via a single intermediate buffer per copy when `D3D12_FEATURE_DATA_D3D12_OPTIONS13.UnrestrictedBufferTextureCopyPitchSupported` is `false`. By @ErichDonGubler in [#7721](https://github.com/gfx-rs/wgpu/pull/7721).
 
+#### hal
+
+- `DropCallback`s are now called after dropping all other fields of their parent structs. By @jerzywilczek in [#99999](https://github.com/gfx-rs/wgpu/pull/99999)
+
 ## v27.0.2 (2025-10-03)
 
 ### Bug Fixes

wgpu-hal/src/gles/mod.rs

@@ -408,13 +408,13 @@ impl TextureInner {
 #[derive(Debug)]
 pub struct Texture {
     pub inner: TextureInner,
-    pub drop_guard: Option<crate::DropGuard>,
     pub mip_level_count: u32,
     pub array_layer_count: u32,
     pub format: wgt::TextureFormat,
     #[allow(unused)]
     pub format_desc: TextureFormatDesc,
     pub copy_size: CopyExtent,
+    pub drop_guard: Option<crate::DropGuard>,
 }
 
 impl crate::DynTexture for Texture {}

wgpu-hal/src/vulkan/mod.rs

@@ -156,7 +156,6 @@ pub struct DebugUtilsMessengerUserData {
 pub struct InstanceShared {
     raw: ash::Instance,
     extensions: Vec<&'static CStr>,
-    drop_guard: Option<crate::DropGuard>,
     flags: wgt::InstanceFlags,
     memory_budget_thresholds: wgt::MemoryBudgetThresholds,
     debug_utils: Option<DebugUtils>,
@@ -171,6 +170,7 @@ pub struct InstanceShared {
     /// It is associated with a `VkInstance` and its children,
     /// except for a `VkPhysicalDevice` and its children.
     instance_api_version: u32,
+    drop_guard: Option<crate::DropGuard>,
 }
 
 pub struct Instance {
@@ -715,7 +715,6 @@ struct DeviceShared {
     family_index: u32,
     queue_index: u32,
     raw_queue: vk::Queue,
-    drop_guard: Option<crate::DropGuard>,
     instance: Arc<InstanceShared>,
     physical_device: vk::PhysicalDevice,
     enabled_extensions: Vec<&'static CStr>,
@@ -737,6 +736,7 @@ struct DeviceShared {
     texture_identity_factory: ResourceIdentityFactory<vk::Image>,
     /// As above, for texture views.
     texture_view_identity_factory: ResourceIdentityFactory<vk::ImageView>,
+    drop_guard: Option<crate::DropGuard>,
 }
 
 impl Drop for DeviceShared {
@@ -945,12 +945,12 @@ impl crate::DynAccelerationStructure for AccelerationStructure {}
 #[derive(Debug)]
 pub struct Texture {
     raw: vk::Image,
-    drop_guard: Option<crate::DropGuard>,
     external_memory: Option<vk::DeviceMemory>,
     block: Option<gpu_alloc::MemoryBlock<vk::DeviceMemory>>,
     format: wgt::TextureFormat,
     copy_size: crate::CopyExtent,
     identity: ResourceIdentity<vk::Image>,
+    drop_guard: Option<crate::DropGuard>,
 }
 
 impl crate::DynTexture for Texture {}