From 2fb2dbf65b7ff8eea72aaba19574bed55ba5bb07 Mon Sep 17 00:00:00 2001
From: sagudev <16504129+sagudev@users.noreply.github.com>
Date: Tue, 15 Apr 2025 10:30:53 +0200
Subject: [PATCH 1/5] Add downcast to `Dyn*`

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
---
 wgpu/src/backend/custom.rs |  9 +++++++++
 wgpu/src/dispatch.rs       | 14 +++++++++++++-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/wgpu/src/backend/custom.rs b/wgpu/src/backend/custom.rs
index 471ccb88ec2..f82e1150b28 100644
--- a/wgpu/src/backend/custom.rs
+++ b/wgpu/src/backend/custom.rs
@@ -18,6 +18,11 @@ macro_rules! dyn_type {
             pub(crate) fn new<T: $interface>(t: T) -> Self {
                 Self(Arc::new(t))
             }
+
+            #[allow(clippy::allow_attributes, dead_code)]
+            pub(crate) fn downcast<T: $interface>(&self) -> Option<&T> {
+                self.0.as_ref().as_any().downcast_ref()
+            }
         }
 
         impl core::ops::Deref for $name {
@@ -46,6 +51,10 @@ macro_rules! dyn_type {
             pub(crate) fn new<T: $interface>(t: T) -> Self {
                 Self(Arc::new(t))
             }
+
+            pub(crate) fn downcast<T: $interface>(&self) -> Option<&T> {
+                self.0.as_ref().as_any().downcast_ref()
+            }
         }
 
         impl core::ops::Deref for $name {
diff --git a/wgpu/src/dispatch.rs b/wgpu/src/dispatch.rs
index 37cf420f48f..f802848c28a 100644
--- a/wgpu/src/dispatch.rs
+++ b/wgpu/src/dispatch.rs
@@ -54,8 +54,20 @@ pub type BufferMapCallback = Box<dyn FnOnce(Result<(), crate::BufferAsyncError>)
 #[cfg(not(send_sync))]
 pub type BufferMapCallback = Box<dyn FnOnce(Result<(), crate::BufferAsyncError>) + 'static>;
 
+// remove when rust 1.86
+#[cfg_attr(not(custom), expect(dead_code))]
+pub trait AsAny {
+    fn as_any(&self) -> &dyn Any;
+}
+
+impl<T: 'static> AsAny for T {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+}
+
 // Common traits on all the interface traits
-trait_alias!(CommonTraits: Any + Debug + WasmNotSendSync);
+trait_alias!(CommonTraits: AsAny + Any + Debug + WasmNotSendSync);
 
 pub trait InstanceInterface: CommonTraits {
     fn new(desc: &crate::InstanceDescriptor) -> Self

From 7fde0618529377cfa96b84537b10750606ef6cb3 Mon Sep 17 00:00:00 2001
From: sagudev <16504129+sagudev@users.noreply.github.com>
Date: Tue, 15 Apr 2025 10:31:24 +0200
Subject: [PATCH 2/5] Add `as_custom`

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
---
 wgpu/src/api/adapter.rs               |  6 +++++
 wgpu/src/api/bind_group.rs            |  8 +++++++
 wgpu/src/api/bind_group_layout.rs     |  8 +++++++
 wgpu/src/api/blas.rs                  |  6 +++++
 wgpu/src/api/buffer.rs                |  6 +++++
 wgpu/src/api/command_buffer.rs        |  8 +++++++
 wgpu/src/api/command_encoder.rs       |  8 +++++++
 wgpu/src/api/compute_pass.rs          |  6 +++++
 wgpu/src/api/compute_pipeline.rs      |  8 +++++++
 wgpu/src/api/device.rs                |  6 +++++
 wgpu/src/api/instance.rs              |  6 +++++
 wgpu/src/api/pipeline_cache.rs        |  6 +++++
 wgpu/src/api/pipeline_layout.rs       |  8 +++++++
 wgpu/src/api/query_set.rs             |  8 +++++++
 wgpu/src/api/queue.rs                 | 32 ++++++++++++++++++++-------
 wgpu/src/api/render_bundle.rs         |  8 +++++++
 wgpu/src/api/render_bundle_encoder.rs |  8 +++++++
 wgpu/src/api/render_pass.rs           |  8 +++++++
 wgpu/src/api/render_pipeline.rs       |  8 +++++++
 wgpu/src/api/sampler.rs               |  8 +++++++
 wgpu/src/api/shader_module.rs         |  8 +++++++
 wgpu/src/api/surface.rs               |  6 +++++
 wgpu/src/api/surface_texture.rs       |  6 +++++
 wgpu/src/api/texture.rs               |  8 +++++++
 wgpu/src/api/texture_view.rs          |  8 +++++++
 wgpu/src/api/tlas.rs                  |  6 +++++
 wgpu/src/dispatch.rs                  | 20 +++++++++++++++++
 27 files changed, 224 insertions(+), 8 deletions(-)

diff --git a/wgpu/src/api/adapter.rs b/wgpu/src/api/adapter.rs
index 614f43bae6c..d1c3a7c296e 100644
--- a/wgpu/src/api/adapter.rs
+++ b/wgpu/src/api/adapter.rs
@@ -133,6 +133,12 @@ impl Adapter {
         }
     }
 
+    #[cfg(custom)]
+    /// Returns custom implementation of adapter (if custom backend and is internally T)
+    pub fn as_custom<T: custom::AdapterInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+
     #[cfg(custom)]
     /// Creates Adapter from custom implementation
     pub fn from_custom<T: custom::AdapterInterface>(adapter: T) -> Self {
diff --git a/wgpu/src/api/bind_group.rs b/wgpu/src/api/bind_group.rs
index d9c27bdc4c5..86c70dea932 100644
--- a/wgpu/src/api/bind_group.rs
+++ b/wgpu/src/api/bind_group.rs
@@ -17,6 +17,14 @@ static_assertions::assert_impl_all!(BindGroup: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(BindGroup => .inner);
 
+impl BindGroup {
+    #[cfg(custom)]
+    /// Returns custom implementation of BindGroup (if custom backend and is internally T)
+    pub fn as_custom<T: custom::BindGroupInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Resource to be bound by a [`BindGroup`] for use with a pipeline.
 ///
 /// The pipeline’s [`BindGroupLayout`] must contain a matching [`BindingType`].
diff --git a/wgpu/src/api/bind_group_layout.rs b/wgpu/src/api/bind_group_layout.rs
index a55921ccc8b..554538ac539 100644
--- a/wgpu/src/api/bind_group_layout.rs
+++ b/wgpu/src/api/bind_group_layout.rs
@@ -18,6 +18,14 @@ pub struct BindGroupLayout {
 #[cfg(send_sync)]
 static_assertions::assert_impl_all!(BindGroupLayout: Send, Sync);
 
+impl BindGroupLayout {
+    #[cfg(custom)]
+    /// Returns custom implementation of BindGroupLayout (if custom backend and is internally T)
+    pub fn as_custom<T: custom::BindGroupLayoutInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 crate::cmp::impl_eq_ord_hash_proxy!(BindGroupLayout => .inner);
 
 /// Describes a [`BindGroupLayout`].
diff --git a/wgpu/src/api/blas.rs b/wgpu/src/api/blas.rs
index 3ab53098f75..777da660e04 100644
--- a/wgpu/src/api/blas.rs
+++ b/wgpu/src/api/blas.rs
@@ -174,6 +174,12 @@ impl Blas {
             hal_blas_callback(None)
         }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of Blas (if custom backend and is internally T)
+    pub fn as_custom<T: crate::custom::BlasInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
 
 /// Context version of [BlasTriangleGeometry].
diff --git a/wgpu/src/api/buffer.rs b/wgpu/src/api/buffer.rs
index 089c743a08f..634e1913134 100644
--- a/wgpu/src/api/buffer.rs
+++ b/wgpu/src/api/buffer.rs
@@ -386,6 +386,12 @@ impl Buffer {
     ) -> BufferViewMut<'_> {
         self.slice(bounds).get_mapped_range_mut()
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of Buffer (if custom backend and is internally T)
+    pub fn as_custom<T: custom::BufferInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
 
 /// A slice of a [`Buffer`], to be mapped, used for vertex or index data, or the like.
diff --git a/wgpu/src/api/command_buffer.rs b/wgpu/src/api/command_buffer.rs
index 00c84af30df..56d6e32129c 100644
--- a/wgpu/src/api/command_buffer.rs
+++ b/wgpu/src/api/command_buffer.rs
@@ -13,3 +13,11 @@ pub struct CommandBuffer {
 }
 #[cfg(send_sync)]
 static_assertions::assert_impl_all!(CommandBuffer: Send, Sync);
+
+impl CommandBuffer {
+    #[cfg(custom)]
+    /// Returns custom implementation of CommandBuffer (if custom backend and is internally T)
+    pub fn as_custom<T: custom::CommandBufferInterface>(&self) -> Option<&T> {
+        self.buffer.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
diff --git a/wgpu/src/api/command_encoder.rs b/wgpu/src/api/command_encoder.rs
index 1cdb9267d41..3014ed3fba9 100644
--- a/wgpu/src/api/command_encoder.rs
+++ b/wgpu/src/api/command_encoder.rs
@@ -26,6 +26,14 @@ static_assertions::assert_impl_all!(CommandEncoder: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(CommandEncoder => .inner);
 
+impl CommandEncoder {
+    #[cfg(custom)]
+    /// Returns custom implementation of CommandEncoder (if custom backend and is internally T)
+    pub fn as_custom<T: custom::CommandEncoderInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Describes a [`CommandEncoder`].
 ///
 /// For use with [`Device::create_command_encoder`].
diff --git a/wgpu/src/api/compute_pass.rs b/wgpu/src/api/compute_pass.rs
index c7fa7462f18..76c2b87f765 100644
--- a/wgpu/src/api/compute_pass.rs
+++ b/wgpu/src/api/compute_pass.rs
@@ -94,6 +94,12 @@ impl ComputePass<'_> {
         self.inner
             .dispatch_workgroups_indirect(&indirect_buffer.inner, indirect_offset);
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of ComputePass (if custom backend and is internally T)
+    pub fn as_custom<T: custom::ComputePassInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
 
 /// [`Features::PUSH_CONSTANTS`] must be enabled on the device in order to call these functions.
diff --git a/wgpu/src/api/compute_pipeline.rs b/wgpu/src/api/compute_pipeline.rs
index 325f0ba1ff2..1886da2ee79 100644
--- a/wgpu/src/api/compute_pipeline.rs
+++ b/wgpu/src/api/compute_pipeline.rs
@@ -15,6 +15,14 @@ static_assertions::assert_impl_all!(ComputePipeline: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(ComputePipeline => .inner);
 
+impl ComputePipeline {
+    #[cfg(custom)]
+    /// Returns custom implementation of ComputePipeline (if custom backend and is internally T)
+    pub fn as_custom<T: custom::ComputePipelineInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl ComputePipeline {
     /// Get an object representing the bind group layout at a given index.
     ///
diff --git a/wgpu/src/api/device.rs b/wgpu/src/api/device.rs
index 44fb837a2c2..34dc28a400f 100644
--- a/wgpu/src/api/device.rs
+++ b/wgpu/src/api/device.rs
@@ -34,6 +34,12 @@ pub type DeviceDescriptor<'a> = wgt::DeviceDescriptor<Label<'a>>;
 static_assertions::assert_impl_all!(DeviceDescriptor<'_>: Send, Sync);
 
 impl Device {
+    #[cfg(custom)]
+    /// Returns custom implementation of Device (if custom backend and is internally T)
+    pub fn as_custom<T: custom::DeviceInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+
     #[cfg(custom)]
     /// Creates Device from custom implementation
     pub fn from_custom<T: custom::DeviceInterface>(device: T) -> Self {
diff --git a/wgpu/src/api/instance.rs b/wgpu/src/api/instance.rs
index dc34a781782..8ed5649aae5 100644
--- a/wgpu/src/api/instance.rs
+++ b/wgpu/src/api/instance.rs
@@ -208,6 +208,12 @@ impl Instance {
         }
     }
 
+    #[cfg(custom)]
+    /// Returns custom implementation of Instance (if custom backend and is internally T)
+    pub fn as_custom<T: custom::InstanceInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+
     /// Retrieves all available [`Adapter`]s that match the given [`Backends`].
     ///
     /// # Arguments
diff --git a/wgpu/src/api/pipeline_cache.rs b/wgpu/src/api/pipeline_cache.rs
index f1cd414f512..41194830b89 100644
--- a/wgpu/src/api/pipeline_cache.rs
+++ b/wgpu/src/api/pipeline_cache.rs
@@ -87,4 +87,10 @@ impl PipelineCache {
     pub fn get_data(&self) -> Option<Vec<u8>> {
         self.inner.get_data()
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of PipelineCache (if custom backend and is internally T)
+    pub fn as_custom<T: custom::PipelineCacheInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
diff --git a/wgpu/src/api/pipeline_layout.rs b/wgpu/src/api/pipeline_layout.rs
index 7baa91555c6..54aaf1bd4aa 100644
--- a/wgpu/src/api/pipeline_layout.rs
+++ b/wgpu/src/api/pipeline_layout.rs
@@ -15,6 +15,14 @@ static_assertions::assert_impl_all!(PipelineLayout: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(PipelineLayout => .inner);
 
+impl PipelineLayout {
+    #[cfg(custom)]
+    /// Returns custom implementation of PipelineLayout (if custom backend and is internally T)
+    pub fn as_custom<T: custom::PipelineLayoutInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Describes a [`PipelineLayout`].
 ///
 /// For use with [`Device::create_pipeline_layout`].
diff --git a/wgpu/src/api/query_set.rs b/wgpu/src/api/query_set.rs
index 24b5a028097..c451bd27246 100644
--- a/wgpu/src/api/query_set.rs
+++ b/wgpu/src/api/query_set.rs
@@ -15,6 +15,14 @@ static_assertions::assert_impl_all!(QuerySet: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(QuerySet => .inner);
 
+impl QuerySet {
+    #[cfg(custom)]
+    /// Returns custom implementation of QuerySet (if custom backend and is internally T)
+    pub fn as_custom<T: custom::QuerySetInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Describes a [`QuerySet`].
 ///
 /// For use with [`Device::create_query_set`].
diff --git a/wgpu/src/api/queue.rs b/wgpu/src/api/queue.rs
index b1868738e98..a6a8c4b78c1 100644
--- a/wgpu/src/api/queue.rs
+++ b/wgpu/src/api/queue.rs
@@ -19,6 +19,22 @@ static_assertions::assert_impl_all!(Queue: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(Queue => .inner);
 
+impl Queue {
+    #[cfg(custom)]
+    /// Returns custom implementation of Queue (if custom backend and is internally T)
+    pub fn as_custom<T: custom::QueueInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+
+    #[cfg(custom)]
+    /// Creates Queue from custom implementation
+    pub fn from_custom<T: custom::QueueInterface>(queue: T) -> Self {
+        Self {
+            inner: dispatch::DispatchQueue::custom(queue),
+        }
+    }
+}
+
 /// Identifier for a particular call to [`Queue::submit`]. Can be used
 /// as part of an argument to [`Device::poll`] to block for a particular
 /// submission to finish.
@@ -52,6 +68,14 @@ pub struct QueueWriteBufferView<'a> {
 #[cfg(send_sync)]
 static_assertions::assert_impl_all!(QueueWriteBufferView<'_>: Send, Sync);
 
+impl QueueWriteBufferView<'_> {
+    #[cfg(custom)]
+    /// Returns custom implementation of QueueWriteBufferView (if custom backend and is internally T)
+    pub fn as_custom<T: custom::QueueWriteBufferInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl Deref for QueueWriteBufferView<'_> {
     type Target = [u8];
 
@@ -82,14 +106,6 @@ impl Drop for QueueWriteBufferView<'_> {
 }
 
 impl Queue {
-    #[cfg(custom)]
-    /// Creates Queue from custom implementation
-    pub fn from_custom<T: custom::QueueInterface>(queue: T) -> Self {
-        Self {
-            inner: dispatch::DispatchQueue::custom(queue),
-        }
-    }
-
     /// Copies the bytes of `data` into `buffer` starting at `offset`.
     ///
     /// The data must be written fully in-bounds, that is, `offset + data.len() <= buffer.len()`.
diff --git a/wgpu/src/api/render_bundle.rs b/wgpu/src/api/render_bundle.rs
index 95de9762078..9635ae0ce43 100644
--- a/wgpu/src/api/render_bundle.rs
+++ b/wgpu/src/api/render_bundle.rs
@@ -18,6 +18,14 @@ static_assertions::assert_impl_all!(RenderBundle: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderBundle => .inner);
 
+impl RenderBundle {
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderBundle (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderBundleInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Describes a [`RenderBundle`].
 ///
 /// For use with [`RenderBundleEncoder::finish`].
diff --git a/wgpu/src/api/render_bundle_encoder.rs b/wgpu/src/api/render_bundle_encoder.rs
index bd64dbbc7cd..8b2560f5351 100644
--- a/wgpu/src/api/render_bundle_encoder.rs
+++ b/wgpu/src/api/render_bundle_encoder.rs
@@ -25,6 +25,14 @@ static_assertions::assert_not_impl_any!(RenderBundleEncoder<'_>: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderBundleEncoder<'_> => .inner);
 
+impl RenderBundleEncoder<'_> {
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderBundleEncoder (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderBundleEncoderInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Describes a [`RenderBundleEncoder`].
 ///
 /// For use with [`Device::create_render_bundle_encoder`].
diff --git a/wgpu/src/api/render_pass.rs b/wgpu/src/api/render_pass.rs
index 6c30543f624..61e212086b6 100644
--- a/wgpu/src/api/render_pass.rs
+++ b/wgpu/src/api/render_pass.rs
@@ -36,6 +36,14 @@ static_assertions::assert_impl_all!(RenderPass<'_>: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderPass<'_> => .inner);
 
+impl RenderPass<'_> {
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderPass (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderPassInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl RenderPass<'_> {
     /// Drops the lifetime relationship to the parent command encoder, making usage of
     /// the encoder while this pass is recorded a run-time error instead.
diff --git a/wgpu/src/api/render_pipeline.rs b/wgpu/src/api/render_pipeline.rs
index 5ef23ff0de7..12375cda73d 100644
--- a/wgpu/src/api/render_pipeline.rs
+++ b/wgpu/src/api/render_pipeline.rs
@@ -17,6 +17,14 @@ static_assertions::assert_impl_all!(RenderPipeline: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderPipeline => .inner);
 
+impl RenderPipeline {
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderPipeline (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderPipelineInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl RenderPipeline {
     /// Get an object representing the bind group layout at a given index.
     ///
diff --git a/wgpu/src/api/sampler.rs b/wgpu/src/api/sampler.rs
index 49c988e85f0..fde912b3c72 100644
--- a/wgpu/src/api/sampler.rs
+++ b/wgpu/src/api/sampler.rs
@@ -18,6 +18,14 @@ static_assertions::assert_impl_all!(Sampler: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(Sampler => .inner);
 
+impl Sampler {
+    #[cfg(custom)]
+    /// Returns custom implementation of Sampler (if custom backend and is internally T)
+    pub fn as_custom<T: custom::SamplerInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 /// Describes a [`Sampler`].
 ///
 /// For use with [`Device::create_sampler`].
diff --git a/wgpu/src/api/shader_module.rs b/wgpu/src/api/shader_module.rs
index 940d6363215..5c6dba421fc 100644
--- a/wgpu/src/api/shader_module.rs
+++ b/wgpu/src/api/shader_module.rs
@@ -24,6 +24,14 @@ static_assertions::assert_impl_all!(ShaderModule: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(ShaderModule => .inner);
 
+impl ShaderModule {
+    #[cfg(custom)]
+    /// Returns custom implementation of ShaderModule (if custom backend and is internally T)
+    pub fn as_custom<T: custom::ShaderModuleInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl ShaderModule {
     /// Get the compilation info for the shader module.
     pub fn get_compilation_info(&self) -> impl Future<Output = CompilationInfo> + WasmNotSend {
diff --git a/wgpu/src/api/surface.rs b/wgpu/src/api/surface.rs
index bc94a4d21f7..4970b5c19c8 100644
--- a/wgpu/src/api/surface.rs
+++ b/wgpu/src/api/surface.rs
@@ -171,6 +171,12 @@ impl Surface<'_> {
             hal_surface_callback(None)
         }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of Surface (if custom backend and is internally T)
+    pub fn as_custom<T: custom::SurfaceInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
 
 // This custom implementation is required because [`Surface::_surface`] doesn't
diff --git a/wgpu/src/api/surface_texture.rs b/wgpu/src/api/surface_texture.rs
index 7ceeffb9550..23dbf99b889 100644
--- a/wgpu/src/api/surface_texture.rs
+++ b/wgpu/src/api/surface_texture.rs
@@ -38,6 +38,12 @@ impl SurfaceTexture {
         self.presented = true;
         self.detail.present();
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of SurfaceTexture (if custom backend and is internally T)
+    pub fn as_custom<T: crate::custom::SurfaceOutputDetailInterface>(&self) -> Option<&T> {
+        self.detail.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
 
 impl Drop for SurfaceTexture {
diff --git a/wgpu/src/api/texture.rs b/wgpu/src/api/texture.rs
index 8ac80e6505c..d0ac76eab0d 100644
--- a/wgpu/src/api/texture.rs
+++ b/wgpu/src/api/texture.rs
@@ -15,6 +15,14 @@ static_assertions::assert_impl_all!(Texture: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(Texture => .inner);
 
+impl Texture {
+    #[cfg(custom)]
+    /// Returns custom implementation of Texture (if custom backend and is internally T)
+    pub fn as_custom<T: custom::TextureInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl Texture {
     /// Returns the inner hal Texture using a callback. The hal texture will be `None` if the
     /// backend type argument does not match with this wgpu Texture
diff --git a/wgpu/src/api/texture_view.rs b/wgpu/src/api/texture_view.rs
index 1fff6f86b7a..f7039502340 100644
--- a/wgpu/src/api/texture_view.rs
+++ b/wgpu/src/api/texture_view.rs
@@ -18,6 +18,14 @@ static_assertions::assert_impl_all!(TextureView: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(TextureView => .inner);
 
+impl TextureView {
+    #[cfg(custom)]
+    /// Returns custom implementation of TextureView (if custom backend and is internally T)
+    pub fn as_custom<T: custom::TextureViewInterface>(&self) -> Option<&T> {
+        self.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
+}
+
 impl TextureView {
     /// Returns the inner hal `TextureView` using a callback. The hal texture will be `None` if the
     /// backend type argument does not match with this wgpu Texture
diff --git a/wgpu/src/api/tlas.rs b/wgpu/src/api/tlas.rs
index 5ea33620ffe..1149bd6c718 100644
--- a/wgpu/src/api/tlas.rs
+++ b/wgpu/src/api/tlas.rs
@@ -57,6 +57,12 @@ impl Tlas {
             hal_tlas_callback(None)
         }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of Tlas (if custom backend and is internally T)
+    pub fn as_custom<T: crate::custom::TlasInterface>(&self) -> Option<&T> {
+        self.shared.inner.as_custom_opt().and_then(|c| c.downcast())
+    }
 }
 
 /// Entry for a top level acceleration structure build.
diff --git a/wgpu/src/dispatch.rs b/wgpu/src/dispatch.rs
index f802848c28a..ca3bb4fba8c 100644
--- a/wgpu/src/dispatch.rs
+++ b/wgpu/src/dispatch.rs
@@ -587,6 +587,16 @@ macro_rules! dispatch_types {
                 }
             }
 
+            #[cfg(custom)]
+            #[inline]
+            #[allow(clippy::allow_attributes, unused)]
+            pub(crate) fn as_custom_opt(&self) -> Option<&$custom_type> {
+                match self {
+                    Self::Custom(value) => Some(value),
+                    _ => None,
+                }
+            }
+
             #[cfg(webgpu)]
             #[inline]
             #[allow(clippy::allow_attributes, unused)]
@@ -705,6 +715,16 @@ macro_rules! dispatch_types {
                 }
             }
 
+            #[cfg(custom)]
+            #[inline]
+            #[allow(clippy::allow_attributes, unused)]
+            pub(crate) fn as_custom_opt(&self) -> Option<&$custom_type> {
+                match self {
+                    Self::Custom(value) => Some(value),
+                    _ => None,
+                }
+            }
+
             #[cfg(webgpu)]
             #[inline]
             #[allow(clippy::allow_attributes, unused)]

From 4c3852222e690c44ef04ee2fa02c60934fcf2811 Mon Sep 17 00:00:00 2001
From: sagudev <16504129+sagudev@users.noreply.github.com>
Date: Tue, 15 Apr 2025 10:31:35 +0200
Subject: [PATCH 3/5] Add tests as more advance example

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
---
 .../standalone/custom_backend/src/custom.rs   | 22 ++++++++++++++-----
 .../standalone/custom_backend/src/main.rs     | 18 +++++++++++++--
 2 files changed, 32 insertions(+), 8 deletions(-)

diff --git a/examples/standalone/custom_backend/src/custom.rs b/examples/standalone/custom_backend/src/custom.rs
index c3815fbbab9..8192379ec3f 100644
--- a/examples/standalone/custom_backend/src/custom.rs
+++ b/examples/standalone/custom_backend/src/custom.rs
@@ -3,9 +3,9 @@ use std::pin::Pin;
 use std::sync::Arc;
 
 use wgpu::custom::{
-    AdapterInterface, DeviceInterface, DispatchAdapter, DispatchDevice, DispatchQueue,
-    DispatchShaderModule, DispatchSurface, InstanceInterface, QueueInterface, RequestAdapterFuture,
-    ShaderModuleInterface,
+    AdapterInterface, ComputePipelineInterface, DeviceInterface, DispatchAdapter, DispatchDevice,
+    DispatchQueue, DispatchShaderModule, DispatchSurface, InstanceInterface, QueueInterface,
+    RequestAdapterFuture, ShaderModuleInterface,
 };
 
 #[derive(Debug, Clone)]
@@ -163,9 +163,10 @@ impl DeviceInterface for CustomDevice {
 
     fn create_compute_pipeline(
         &self,
-        _desc: &wgpu::ComputePipelineDescriptor<'_>,
+        desc: &wgpu::ComputePipelineDescriptor<'_>,
     ) -> wgpu::custom::DispatchComputePipeline {
-        unimplemented!()
+        let module = desc.module.as_custom::<CustomShaderModule>().unwrap();
+        wgpu::custom::DispatchComputePipeline::custom(CustomComputePipeline(module.0.clone()))
     }
 
     unsafe fn create_pipeline_cache(
@@ -262,7 +263,7 @@ impl DeviceInterface for CustomDevice {
 }
 
 #[derive(Debug)]
-struct CustomShaderModule(Counter);
+pub struct CustomShaderModule(pub Counter);
 
 impl ShaderModuleInterface for CustomShaderModule {
     fn get_compilation_info(&self) -> Pin<Box<dyn wgpu::custom::ShaderCompilationInfoFuture>> {
@@ -343,3 +344,12 @@ impl QueueInterface for CustomQueue {
         unimplemented!()
     }
 }
+
+#[derive(Debug)]
+pub struct CustomComputePipeline(pub Counter);
+
+impl ComputePipelineInterface for CustomComputePipeline {
+    fn get_bind_group_layout(&self, _index: u32) -> wgpu::custom::DispatchBindGroupLayout {
+        unimplemented!()
+    }
+}
diff --git a/examples/standalone/custom_backend/src/main.rs b/examples/standalone/custom_backend/src/main.rs
index 11f05e98ea8..1582bcc7d6b 100644
--- a/examples/standalone/custom_backend/src/main.rs
+++ b/examples/standalone/custom_backend/src/main.rs
@@ -1,6 +1,6 @@
 use std::marker::PhantomData;
 
-use custom::Counter;
+use custom::{Counter, CustomShaderModule};
 use wgpu::{DeviceDescriptor, RequestAdapterOptions};
 
 mod custom;
@@ -31,12 +31,26 @@ async fn main() {
             .unwrap();
         assert_eq!(counter.count(), 5);
 
-        let _module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+        let module = device.create_shader_module(wgpu::ShaderModuleDescriptor {
             label: Some("shader"),
             source: wgpu::ShaderSource::Dummy(PhantomData),
         });
 
+        let custom_module = module.as_custom::<CustomShaderModule>().unwrap();
+        assert_eq!(custom_module.0.count(), 6);
+        let _module_clone = module.clone();
         assert_eq!(counter.count(), 6);
+
+        let _pipeline = device.create_compute_pipeline(&wgpu::ComputePipelineDescriptor {
+            label: None,
+            layout: None,
+            module: &module,
+            entry_point: None,
+            compilation_options: Default::default(),
+            cache: None,
+        });
+
+        assert_eq!(counter.count(), 7);
     }
     assert_eq!(counter.count(), 1);
 }

From 3e758ee17523cc04a3749ded92711a5b4ba8a557 Mon Sep 17 00:00:00 2001
From: sagudev <16504129+sagudev@users.noreply.github.com>
Date: Thu, 17 Apr 2025 12:15:12 +0200
Subject: [PATCH 4/5] Expose as_custom on Dispatch types too

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
---
 wgpu/src/api/adapter.rs               | 2 +-
 wgpu/src/api/bind_group.rs            | 2 +-
 wgpu/src/api/bind_group_layout.rs     | 2 +-
 wgpu/src/api/blas.rs                  | 2 +-
 wgpu/src/api/buffer.rs                | 2 +-
 wgpu/src/api/command_buffer.rs        | 2 +-
 wgpu/src/api/command_encoder.rs       | 2 +-
 wgpu/src/api/compute_pass.rs          | 2 +-
 wgpu/src/api/compute_pipeline.rs      | 2 +-
 wgpu/src/api/device.rs                | 2 +-
 wgpu/src/api/instance.rs              | 2 +-
 wgpu/src/api/pipeline_cache.rs        | 2 +-
 wgpu/src/api/pipeline_layout.rs       | 2 +-
 wgpu/src/api/query_set.rs             | 2 +-
 wgpu/src/api/queue.rs                 | 4 ++--
 wgpu/src/api/render_bundle.rs         | 2 +-
 wgpu/src/api/render_bundle_encoder.rs | 2 +-
 wgpu/src/api/render_pass.rs           | 2 +-
 wgpu/src/api/render_pipeline.rs       | 2 +-
 wgpu/src/api/sampler.rs               | 2 +-
 wgpu/src/api/shader_module.rs         | 2 +-
 wgpu/src/api/surface.rs               | 2 +-
 wgpu/src/api/surface_texture.rs       | 2 +-
 wgpu/src/api/texture.rs               | 2 +-
 wgpu/src/api/texture_view.rs          | 2 +-
 wgpu/src/api/tlas.rs                  | 2 +-
 wgpu/src/dispatch.rs                  | 8 ++++----
 27 files changed, 31 insertions(+), 31 deletions(-)

diff --git a/wgpu/src/api/adapter.rs b/wgpu/src/api/adapter.rs
index d1c3a7c296e..3b83ccc0f46 100644
--- a/wgpu/src/api/adapter.rs
+++ b/wgpu/src/api/adapter.rs
@@ -136,7 +136,7 @@ impl Adapter {
     #[cfg(custom)]
     /// Returns custom implementation of adapter (if custom backend and is internally T)
     pub fn as_custom<T: custom::AdapterInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 
     #[cfg(custom)]
diff --git a/wgpu/src/api/bind_group.rs b/wgpu/src/api/bind_group.rs
index 86c70dea932..2f4ae007ff6 100644
--- a/wgpu/src/api/bind_group.rs
+++ b/wgpu/src/api/bind_group.rs
@@ -21,7 +21,7 @@ impl BindGroup {
     #[cfg(custom)]
     /// Returns custom implementation of BindGroup (if custom backend and is internally T)
     pub fn as_custom<T: custom::BindGroupInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/bind_group_layout.rs b/wgpu/src/api/bind_group_layout.rs
index 554538ac539..a7a50ca7270 100644
--- a/wgpu/src/api/bind_group_layout.rs
+++ b/wgpu/src/api/bind_group_layout.rs
@@ -22,7 +22,7 @@ impl BindGroupLayout {
     #[cfg(custom)]
     /// Returns custom implementation of BindGroupLayout (if custom backend and is internally T)
     pub fn as_custom<T: custom::BindGroupLayoutInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/blas.rs b/wgpu/src/api/blas.rs
index 777da660e04..82c976b98df 100644
--- a/wgpu/src/api/blas.rs
+++ b/wgpu/src/api/blas.rs
@@ -178,7 +178,7 @@ impl Blas {
     #[cfg(custom)]
     /// Returns custom implementation of Blas (if custom backend and is internally T)
     pub fn as_custom<T: crate::custom::BlasInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/buffer.rs b/wgpu/src/api/buffer.rs
index 634e1913134..c962c8d65ca 100644
--- a/wgpu/src/api/buffer.rs
+++ b/wgpu/src/api/buffer.rs
@@ -390,7 +390,7 @@ impl Buffer {
     #[cfg(custom)]
     /// Returns custom implementation of Buffer (if custom backend and is internally T)
     pub fn as_custom<T: custom::BufferInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/command_buffer.rs b/wgpu/src/api/command_buffer.rs
index 56d6e32129c..eb1358946aa 100644
--- a/wgpu/src/api/command_buffer.rs
+++ b/wgpu/src/api/command_buffer.rs
@@ -18,6 +18,6 @@ impl CommandBuffer {
     #[cfg(custom)]
     /// Returns custom implementation of CommandBuffer (if custom backend and is internally T)
     pub fn as_custom<T: custom::CommandBufferInterface>(&self) -> Option<&T> {
-        self.buffer.as_custom_opt().and_then(|c| c.downcast())
+        self.buffer.as_custom()
     }
 }
diff --git a/wgpu/src/api/command_encoder.rs b/wgpu/src/api/command_encoder.rs
index 3014ed3fba9..b53d65168d1 100644
--- a/wgpu/src/api/command_encoder.rs
+++ b/wgpu/src/api/command_encoder.rs
@@ -30,7 +30,7 @@ impl CommandEncoder {
     #[cfg(custom)]
     /// Returns custom implementation of CommandEncoder (if custom backend and is internally T)
     pub fn as_custom<T: custom::CommandEncoderInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/compute_pass.rs b/wgpu/src/api/compute_pass.rs
index 76c2b87f765..18d2f30eeb6 100644
--- a/wgpu/src/api/compute_pass.rs
+++ b/wgpu/src/api/compute_pass.rs
@@ -98,7 +98,7 @@ impl ComputePass<'_> {
     #[cfg(custom)]
     /// Returns custom implementation of ComputePass (if custom backend and is internally T)
     pub fn as_custom<T: custom::ComputePassInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/compute_pipeline.rs b/wgpu/src/api/compute_pipeline.rs
index 1886da2ee79..86e39427baa 100644
--- a/wgpu/src/api/compute_pipeline.rs
+++ b/wgpu/src/api/compute_pipeline.rs
@@ -19,7 +19,7 @@ impl ComputePipeline {
     #[cfg(custom)]
     /// Returns custom implementation of ComputePipeline (if custom backend and is internally T)
     pub fn as_custom<T: custom::ComputePipelineInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/device.rs b/wgpu/src/api/device.rs
index 34dc28a400f..637ca9310e0 100644
--- a/wgpu/src/api/device.rs
+++ b/wgpu/src/api/device.rs
@@ -37,7 +37,7 @@ impl Device {
     #[cfg(custom)]
     /// Returns custom implementation of Device (if custom backend and is internally T)
     pub fn as_custom<T: custom::DeviceInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 
     #[cfg(custom)]
diff --git a/wgpu/src/api/instance.rs b/wgpu/src/api/instance.rs
index 8ed5649aae5..24815df64b0 100644
--- a/wgpu/src/api/instance.rs
+++ b/wgpu/src/api/instance.rs
@@ -211,7 +211,7 @@ impl Instance {
     #[cfg(custom)]
     /// Returns custom implementation of Instance (if custom backend and is internally T)
     pub fn as_custom<T: custom::InstanceInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 
     /// Retrieves all available [`Adapter`]s that match the given [`Backends`].
diff --git a/wgpu/src/api/pipeline_cache.rs b/wgpu/src/api/pipeline_cache.rs
index 41194830b89..c6f161abaf2 100644
--- a/wgpu/src/api/pipeline_cache.rs
+++ b/wgpu/src/api/pipeline_cache.rs
@@ -91,6 +91,6 @@ impl PipelineCache {
     #[cfg(custom)]
     /// Returns custom implementation of PipelineCache (if custom backend and is internally T)
     pub fn as_custom<T: custom::PipelineCacheInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
diff --git a/wgpu/src/api/pipeline_layout.rs b/wgpu/src/api/pipeline_layout.rs
index 54aaf1bd4aa..6bd71093ca0 100644
--- a/wgpu/src/api/pipeline_layout.rs
+++ b/wgpu/src/api/pipeline_layout.rs
@@ -19,7 +19,7 @@ impl PipelineLayout {
     #[cfg(custom)]
     /// Returns custom implementation of PipelineLayout (if custom backend and is internally T)
     pub fn as_custom<T: custom::PipelineLayoutInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/query_set.rs b/wgpu/src/api/query_set.rs
index c451bd27246..dc89330f1b9 100644
--- a/wgpu/src/api/query_set.rs
+++ b/wgpu/src/api/query_set.rs
@@ -19,7 +19,7 @@ impl QuerySet {
     #[cfg(custom)]
     /// Returns custom implementation of QuerySet (if custom backend and is internally T)
     pub fn as_custom<T: custom::QuerySetInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/queue.rs b/wgpu/src/api/queue.rs
index a6a8c4b78c1..790643fbe9a 100644
--- a/wgpu/src/api/queue.rs
+++ b/wgpu/src/api/queue.rs
@@ -23,7 +23,7 @@ impl Queue {
     #[cfg(custom)]
     /// Returns custom implementation of Queue (if custom backend and is internally T)
     pub fn as_custom<T: custom::QueueInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 
     #[cfg(custom)]
@@ -72,7 +72,7 @@ impl QueueWriteBufferView<'_> {
     #[cfg(custom)]
     /// Returns custom implementation of QueueWriteBufferView (if custom backend and is internally T)
     pub fn as_custom<T: custom::QueueWriteBufferInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/render_bundle.rs b/wgpu/src/api/render_bundle.rs
index 9635ae0ce43..2ea592940d0 100644
--- a/wgpu/src/api/render_bundle.rs
+++ b/wgpu/src/api/render_bundle.rs
@@ -22,7 +22,7 @@ impl RenderBundle {
     #[cfg(custom)]
     /// Returns custom implementation of RenderBundle (if custom backend and is internally T)
     pub fn as_custom<T: custom::RenderBundleInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/render_bundle_encoder.rs b/wgpu/src/api/render_bundle_encoder.rs
index 8b2560f5351..56b6f841620 100644
--- a/wgpu/src/api/render_bundle_encoder.rs
+++ b/wgpu/src/api/render_bundle_encoder.rs
@@ -29,7 +29,7 @@ impl RenderBundleEncoder<'_> {
     #[cfg(custom)]
     /// Returns custom implementation of RenderBundleEncoder (if custom backend and is internally T)
     pub fn as_custom<T: custom::RenderBundleEncoderInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/render_pass.rs b/wgpu/src/api/render_pass.rs
index 61e212086b6..0af43c44009 100644
--- a/wgpu/src/api/render_pass.rs
+++ b/wgpu/src/api/render_pass.rs
@@ -40,7 +40,7 @@ impl RenderPass<'_> {
     #[cfg(custom)]
     /// Returns custom implementation of RenderPass (if custom backend and is internally T)
     pub fn as_custom<T: custom::RenderPassInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/render_pipeline.rs b/wgpu/src/api/render_pipeline.rs
index 12375cda73d..d607b2ad94a 100644
--- a/wgpu/src/api/render_pipeline.rs
+++ b/wgpu/src/api/render_pipeline.rs
@@ -21,7 +21,7 @@ impl RenderPipeline {
     #[cfg(custom)]
     /// Returns custom implementation of RenderPipeline (if custom backend and is internally T)
     pub fn as_custom<T: custom::RenderPipelineInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/sampler.rs b/wgpu/src/api/sampler.rs
index fde912b3c72..a8916829c86 100644
--- a/wgpu/src/api/sampler.rs
+++ b/wgpu/src/api/sampler.rs
@@ -22,7 +22,7 @@ impl Sampler {
     #[cfg(custom)]
     /// Returns custom implementation of Sampler (if custom backend and is internally T)
     pub fn as_custom<T: custom::SamplerInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/shader_module.rs b/wgpu/src/api/shader_module.rs
index 5c6dba421fc..dec0d34e900 100644
--- a/wgpu/src/api/shader_module.rs
+++ b/wgpu/src/api/shader_module.rs
@@ -28,7 +28,7 @@ impl ShaderModule {
     #[cfg(custom)]
     /// Returns custom implementation of ShaderModule (if custom backend and is internally T)
     pub fn as_custom<T: custom::ShaderModuleInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/surface.rs b/wgpu/src/api/surface.rs
index 4970b5c19c8..773d0123d9a 100644
--- a/wgpu/src/api/surface.rs
+++ b/wgpu/src/api/surface.rs
@@ -175,7 +175,7 @@ impl Surface<'_> {
     #[cfg(custom)]
     /// Returns custom implementation of Surface (if custom backend and is internally T)
     pub fn as_custom<T: custom::SurfaceInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/surface_texture.rs b/wgpu/src/api/surface_texture.rs
index 23dbf99b889..6758e61a7bf 100644
--- a/wgpu/src/api/surface_texture.rs
+++ b/wgpu/src/api/surface_texture.rs
@@ -42,7 +42,7 @@ impl SurfaceTexture {
     #[cfg(custom)]
     /// Returns custom implementation of SurfaceTexture (if custom backend and is internally T)
     pub fn as_custom<T: crate::custom::SurfaceOutputDetailInterface>(&self) -> Option<&T> {
-        self.detail.as_custom_opt().and_then(|c| c.downcast())
+        self.detail.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/texture.rs b/wgpu/src/api/texture.rs
index d0ac76eab0d..6217a57f3a8 100644
--- a/wgpu/src/api/texture.rs
+++ b/wgpu/src/api/texture.rs
@@ -19,7 +19,7 @@ impl Texture {
     #[cfg(custom)]
     /// Returns custom implementation of Texture (if custom backend and is internally T)
     pub fn as_custom<T: custom::TextureInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/texture_view.rs b/wgpu/src/api/texture_view.rs
index f7039502340..9978d3f8623 100644
--- a/wgpu/src/api/texture_view.rs
+++ b/wgpu/src/api/texture_view.rs
@@ -22,7 +22,7 @@ impl TextureView {
     #[cfg(custom)]
     /// Returns custom implementation of TextureView (if custom backend and is internally T)
     pub fn as_custom<T: custom::TextureViewInterface>(&self) -> Option<&T> {
-        self.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/api/tlas.rs b/wgpu/src/api/tlas.rs
index 1149bd6c718..3a5e7659422 100644
--- a/wgpu/src/api/tlas.rs
+++ b/wgpu/src/api/tlas.rs
@@ -61,7 +61,7 @@ impl Tlas {
     #[cfg(custom)]
     /// Returns custom implementation of Tlas (if custom backend and is internally T)
     pub fn as_custom<T: crate::custom::TlasInterface>(&self) -> Option<&T> {
-        self.shared.inner.as_custom_opt().and_then(|c| c.downcast())
+        self.shared.inner.as_custom()
     }
 }
 
diff --git a/wgpu/src/dispatch.rs b/wgpu/src/dispatch.rs
index ca3bb4fba8c..ca48feca147 100644
--- a/wgpu/src/dispatch.rs
+++ b/wgpu/src/dispatch.rs
@@ -590,9 +590,9 @@ macro_rules! dispatch_types {
             #[cfg(custom)]
             #[inline]
             #[allow(clippy::allow_attributes, unused)]
-            pub(crate) fn as_custom_opt(&self) -> Option<&$custom_type> {
+            pub fn as_custom<T: $interface>(&self) -> Option<&T> {
                 match self {
-                    Self::Custom(value) => Some(value),
+                    Self::Custom(value) => value.downcast(),
                     _ => None,
                 }
             }
@@ -718,9 +718,9 @@ macro_rules! dispatch_types {
             #[cfg(custom)]
             #[inline]
             #[allow(clippy::allow_attributes, unused)]
-            pub(crate) fn as_custom_opt(&self) -> Option<&$custom_type> {
+            pub fn as_custom<T: $interface>(&self) -> Option<&T> {
                 match self {
-                    Self::Custom(value) => Some(value),
+                    Self::Custom(value) => value.downcast(),
                     _ => None,
                 }
             }

From c82049e85fe6c33ac3ef66fba62ed1afe4cf0999 Mon Sep 17 00:00:00 2001
From: sagudev <16504129+sagudev@users.noreply.github.com>
Date: Fri, 18 Apr 2025 07:09:02 +0200
Subject: [PATCH 5/5] join impls if possible

Signed-off-by: sagudev <16504129+sagudev@users.noreply.github.com>
---
 wgpu/src/api/bind_group_layout.rs     |  4 ++--
 wgpu/src/api/command_encoder.rs       | 14 ++++++--------
 wgpu/src/api/compute_pipeline.rs      | 14 ++++++--------
 wgpu/src/api/render_bundle_encoder.rs | 14 ++++++--------
 wgpu/src/api/render_pass.rs           | 14 ++++++--------
 wgpu/src/api/render_pipeline.rs       | 14 ++++++--------
 wgpu/src/api/shader_module.rs         | 12 +++++-------
 wgpu/src/api/texture.rs               | 14 ++++++--------
 wgpu/src/api/texture_view.rs          | 14 ++++++--------
 9 files changed, 49 insertions(+), 65 deletions(-)

diff --git a/wgpu/src/api/bind_group_layout.rs b/wgpu/src/api/bind_group_layout.rs
index a7a50ca7270..62eb7dd4147 100644
--- a/wgpu/src/api/bind_group_layout.rs
+++ b/wgpu/src/api/bind_group_layout.rs
@@ -18,6 +18,8 @@ pub struct BindGroupLayout {
 #[cfg(send_sync)]
 static_assertions::assert_impl_all!(BindGroupLayout: Send, Sync);
 
+crate::cmp::impl_eq_ord_hash_proxy!(BindGroupLayout => .inner);
+
 impl BindGroupLayout {
     #[cfg(custom)]
     /// Returns custom implementation of BindGroupLayout (if custom backend and is internally T)
@@ -26,8 +28,6 @@ impl BindGroupLayout {
     }
 }
 
-crate::cmp::impl_eq_ord_hash_proxy!(BindGroupLayout => .inner);
-
 /// Describes a [`BindGroupLayout`].
 ///
 /// For use with [`Device::create_bind_group_layout`].
diff --git a/wgpu/src/api/command_encoder.rs b/wgpu/src/api/command_encoder.rs
index b53d65168d1..6e91a452844 100644
--- a/wgpu/src/api/command_encoder.rs
+++ b/wgpu/src/api/command_encoder.rs
@@ -26,14 +26,6 @@ static_assertions::assert_impl_all!(CommandEncoder: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(CommandEncoder => .inner);
 
-impl CommandEncoder {
-    #[cfg(custom)]
-    /// Returns custom implementation of CommandEncoder (if custom backend and is internally T)
-    pub fn as_custom<T: custom::CommandEncoderInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 /// Describes a [`CommandEncoder`].
 ///
 /// For use with [`Device::create_command_encoder`].
@@ -270,6 +262,12 @@ impl CommandEncoder {
             hal_command_encoder_callback(None)
         }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of CommandEncoder (if custom backend and is internally T)
+    pub fn as_custom<T: custom::CommandEncoderInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
 }
 
 /// [`Features::TIMESTAMP_QUERY_INSIDE_ENCODERS`] must be enabled on the device in order to call these functions.
diff --git a/wgpu/src/api/compute_pipeline.rs b/wgpu/src/api/compute_pipeline.rs
index 86e39427baa..499f967b540 100644
--- a/wgpu/src/api/compute_pipeline.rs
+++ b/wgpu/src/api/compute_pipeline.rs
@@ -15,14 +15,6 @@ static_assertions::assert_impl_all!(ComputePipeline: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(ComputePipeline => .inner);
 
-impl ComputePipeline {
-    #[cfg(custom)]
-    /// Returns custom implementation of ComputePipeline (if custom backend and is internally T)
-    pub fn as_custom<T: custom::ComputePipelineInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 impl ComputePipeline {
     /// Get an object representing the bind group layout at a given index.
     ///
@@ -35,6 +27,12 @@ impl ComputePipeline {
         let bind_group = self.inner.get_bind_group_layout(index);
         BindGroupLayout { inner: bind_group }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of ComputePipeline (if custom backend and is internally T)
+    pub fn as_custom<T: custom::ComputePipelineInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
 }
 
 /// Describes a compute pipeline.
diff --git a/wgpu/src/api/render_bundle_encoder.rs b/wgpu/src/api/render_bundle_encoder.rs
index 56b6f841620..a33c3cb237b 100644
--- a/wgpu/src/api/render_bundle_encoder.rs
+++ b/wgpu/src/api/render_bundle_encoder.rs
@@ -25,14 +25,6 @@ static_assertions::assert_not_impl_any!(RenderBundleEncoder<'_>: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderBundleEncoder<'_> => .inner);
 
-impl RenderBundleEncoder<'_> {
-    #[cfg(custom)]
-    /// Returns custom implementation of RenderBundleEncoder (if custom backend and is internally T)
-    pub fn as_custom<T: custom::RenderBundleEncoderInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 /// Describes a [`RenderBundleEncoder`].
 ///
 /// For use with [`Device::create_render_bundle_encoder`].
@@ -196,6 +188,12 @@ impl<'a> RenderBundleEncoder<'a> {
         self.inner
             .draw_indexed_indirect(&indirect_buffer.inner, indirect_offset);
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderBundleEncoder (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderBundleEncoderInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
 }
 
 /// [`Features::PUSH_CONSTANTS`] must be enabled on the device in order to call these functions.
diff --git a/wgpu/src/api/render_pass.rs b/wgpu/src/api/render_pass.rs
index 0af43c44009..2a2d3bd08e2 100644
--- a/wgpu/src/api/render_pass.rs
+++ b/wgpu/src/api/render_pass.rs
@@ -36,14 +36,6 @@ static_assertions::assert_impl_all!(RenderPass<'_>: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderPass<'_> => .inner);
 
-impl RenderPass<'_> {
-    #[cfg(custom)]
-    /// Returns custom implementation of RenderPass (if custom backend and is internally T)
-    pub fn as_custom<T: custom::RenderPassInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 impl RenderPass<'_> {
     /// Drops the lifetime relationship to the parent command encoder, making usage of
     /// the encoder while this pass is recorded a run-time error instead.
@@ -332,6 +324,12 @@ impl RenderPass<'_> {
         self.inner
             .multi_draw_indexed_indirect(&indirect_buffer.inner, indirect_offset, count);
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderPass (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderPassInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
 }
 
 /// [`Features::MULTI_DRAW_INDIRECT_COUNT`] must be enabled on the device in order to call these functions.
diff --git a/wgpu/src/api/render_pipeline.rs b/wgpu/src/api/render_pipeline.rs
index d607b2ad94a..13b4f9b5f7b 100644
--- a/wgpu/src/api/render_pipeline.rs
+++ b/wgpu/src/api/render_pipeline.rs
@@ -17,14 +17,6 @@ static_assertions::assert_impl_all!(RenderPipeline: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(RenderPipeline => .inner);
 
-impl RenderPipeline {
-    #[cfg(custom)]
-    /// Returns custom implementation of RenderPipeline (if custom backend and is internally T)
-    pub fn as_custom<T: custom::RenderPipelineInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 impl RenderPipeline {
     /// Get an object representing the bind group layout at a given index.
     ///
@@ -36,6 +28,12 @@ impl RenderPipeline {
         let layout = self.inner.get_bind_group_layout(index);
         BindGroupLayout { inner: layout }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of RenderPipeline (if custom backend and is internally T)
+    pub fn as_custom<T: custom::RenderPipelineInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
 }
 
 /// Specifies an interpretation of the bytes of a vertex buffer as vertex attributes.
diff --git a/wgpu/src/api/shader_module.rs b/wgpu/src/api/shader_module.rs
index dec0d34e900..c4d7a5183e3 100644
--- a/wgpu/src/api/shader_module.rs
+++ b/wgpu/src/api/shader_module.rs
@@ -25,6 +25,11 @@ static_assertions::assert_impl_all!(ShaderModule: Send, Sync);
 crate::cmp::impl_eq_ord_hash_proxy!(ShaderModule => .inner);
 
 impl ShaderModule {
+    /// Get the compilation info for the shader module.
+    pub fn get_compilation_info(&self) -> impl Future<Output = CompilationInfo> + WasmNotSend {
+        self.inner.get_compilation_info()
+    }
+
     #[cfg(custom)]
     /// Returns custom implementation of ShaderModule (if custom backend and is internally T)
     pub fn as_custom<T: custom::ShaderModuleInterface>(&self) -> Option<&T> {
@@ -32,13 +37,6 @@ impl ShaderModule {
     }
 }
 
-impl ShaderModule {
-    /// Get the compilation info for the shader module.
-    pub fn get_compilation_info(&self) -> impl Future<Output = CompilationInfo> + WasmNotSend {
-        self.inner.get_compilation_info()
-    }
-}
-
 /// Compilation information for a shader module.
 ///
 /// Corresponds to [WebGPU `GPUCompilationInfo`](https://gpuweb.github.io/gpuweb/#gpucompilationinfo).
diff --git a/wgpu/src/api/texture.rs b/wgpu/src/api/texture.rs
index 6217a57f3a8..6dff7b6a11e 100644
--- a/wgpu/src/api/texture.rs
+++ b/wgpu/src/api/texture.rs
@@ -15,14 +15,6 @@ static_assertions::assert_impl_all!(Texture: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(Texture => .inner);
 
-impl Texture {
-    #[cfg(custom)]
-    /// Returns custom implementation of Texture (if custom backend and is internally T)
-    pub fn as_custom<T: custom::TextureInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 impl Texture {
     /// Returns the inner hal Texture using a callback. The hal texture will be `None` if the
     /// backend type argument does not match with this wgpu Texture
@@ -45,6 +37,12 @@ impl Texture {
         }
     }
 
+    #[cfg(custom)]
+    /// Returns custom implementation of Texture (if custom backend and is internally T)
+    pub fn as_custom<T: custom::TextureInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
+
     /// Creates a view of this texture, specifying an interpretation of its texels and
     /// possibly a subset of its layers and mip levels.
     ///
diff --git a/wgpu/src/api/texture_view.rs b/wgpu/src/api/texture_view.rs
index 9978d3f8623..e5af89d62e7 100644
--- a/wgpu/src/api/texture_view.rs
+++ b/wgpu/src/api/texture_view.rs
@@ -18,14 +18,6 @@ static_assertions::assert_impl_all!(TextureView: Send, Sync);
 
 crate::cmp::impl_eq_ord_hash_proxy!(TextureView => .inner);
 
-impl TextureView {
-    #[cfg(custom)]
-    /// Returns custom implementation of TextureView (if custom backend and is internally T)
-    pub fn as_custom<T: custom::TextureViewInterface>(&self) -> Option<&T> {
-        self.inner.as_custom()
-    }
-}
-
 impl TextureView {
     /// Returns the inner hal `TextureView` using a callback. The hal texture will be `None` if the
     /// backend type argument does not match with this wgpu Texture
@@ -48,6 +40,12 @@ impl TextureView {
             hal_texture_view_callback(None)
         }
     }
+
+    #[cfg(custom)]
+    /// Returns custom implementation of TextureView (if custom backend and is internally T)
+    pub fn as_custom<T: custom::TextureViewInterface>(&self) -> Option<&T> {
+        self.inner.as_custom()
+    }
 }
 
 /// Describes a [`TextureView`].