diff --git a/Cargo.lock b/Cargo.lock
index 60e311426f..90c4ab1840 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -476,7 +476,7 @@ dependencies = [
 [[package]]
 name = "gfx-auxil"
 version = "0.5.0"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "fxhash",
  "gfx-hal",
@@ -486,7 +486,7 @@ dependencies = [
 [[package]]
 name = "gfx-backend-dx11"
 version = "0.6.0"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "arrayvec",
  "bitflags",
@@ -507,7 +507,7 @@ dependencies = [
 [[package]]
 name = "gfx-backend-dx12"
 version = "0.6.2"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "arrayvec",
  "bit-set",
@@ -527,7 +527,7 @@ dependencies = [
 [[package]]
 name = "gfx-backend-empty"
 version = "0.6.0"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "gfx-hal",
  "log",
@@ -537,7 +537,7 @@ dependencies = [
 [[package]]
 name = "gfx-backend-gl"
 version = "0.6.0"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "arrayvec",
  "bitflags",
@@ -559,7 +559,7 @@ dependencies = [
 [[package]]
 name = "gfx-backend-metal"
 version = "0.6.0"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "arrayvec",
  "bitflags",
@@ -583,7 +583,7 @@ dependencies = [
 [[package]]
 name = "gfx-backend-vulkan"
 version = "0.6.5"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "arrayvec",
  "ash",
@@ -603,7 +603,7 @@ dependencies = [
 [[package]]
 name = "gfx-hal"
 version = "0.6.0"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 dependencies = [
  "bitflags",
  "naga",
@@ -706,9 +706,9 @@ dependencies = [
 
 [[package]]
 name = "inplace_it"
-version = "0.3.2"
+version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd01a2a73f2f399df96b22dc88ea687ef4d76226284e7531ae3c7ee1dc5cb534"
+checksum = "90953f308a79fe6d62a4643e51f848fbfddcd05975a38e69fdf4ab86a7baf7ca"
 
 [[package]]
 name = "instant"
@@ -935,7 +935,7 @@ dependencies = [
 [[package]]
 name = "naga"
 version = "0.2.0"
-source = "git+https://github.com/gfx-rs/naga?tag=gfx-7#0ea8a0a3c2ce1211511d763915fcc511408240c0"
+source = "git+https://github.com/gfx-rs/naga?tag=gfx-8#4a13ce022b666a4896ba1dbcbd82121e8b06ad3e"
 dependencies = [
  "bit-set",
  "bitflags",
@@ -1201,7 +1201,7 @@ dependencies = [
 [[package]]
 name = "range-alloc"
 version = "0.1.1"
-source = "git+https://github.com/gfx-rs/gfx?rev=00285817af676e091ac886b927e9e5e292f22a03#00285817af676e091ac886b927e9e5e292f22a03"
+source = "git+https://github.com/gfx-rs/gfx?rev=2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8#2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8"
 
 [[package]]
 name = "raw-window-handle"
diff --git a/wgpu-core/Cargo.toml b/wgpu-core/Cargo.toml
index cfa1ffea49..453d779c68 100644
--- a/wgpu-core/Cargo.toml
+++ b/wgpu-core/Cargo.toml
@@ -36,28 +36,28 @@ thiserror = "1"
 gpu-alloc = { version = "0.3", features = ["tracing"] }
 gpu-descriptor = { version = "0.1", features = ["tracing"] }
 
-hal = { package = "gfx-hal", git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03" }
-gfx-backend-empty = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03" }
+hal = { package = "gfx-hal", git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8" }
+gfx-backend-empty = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8" }
 
 [target.'cfg(all(not(target_arch = "wasm32"), all(unix, not(target_os = "ios"), not(target_os = "macos"))))'.dependencies]
-gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03", features = ["naga"] }
-gfx-backend-gl = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03", features = ["naga"] }
+gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8", features = ["naga"] }
+gfx-backend-gl = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8", features = ["naga"] }
 
 [target.'cfg(all(not(target_arch = "wasm32"), any(target_os = "ios", target_os = "macos")))'.dependencies]
-gfx-backend-metal = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03", features = ["naga"] }
-gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03", optional = true }
+gfx-backend-metal = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8", features = ["naga"] }
+gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8", optional = true }
 
 [target.'cfg(all(not(target_arch = "wasm32"), windows))'.dependencies]
-gfx-backend-dx12 = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03" }
-gfx-backend-dx11 = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03" }
-gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03", features = ["naga"] }
+gfx-backend-dx12 = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8" }
+gfx-backend-dx11 = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8" }
+gfx-backend-vulkan = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8", features = ["naga"] }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
-gfx-backend-gl = { git = "https://github.com/gfx-rs/gfx", rev = "00285817af676e091ac886b927e9e5e292f22a03", features = ["naga"] }
+gfx-backend-gl = { git = "https://github.com/gfx-rs/gfx", rev = "2fd74dbe1562a3eef05b11dcd300c1c9c9bc12a8", features = ["naga"] }
 
 [dependencies.naga]
 git = "https://github.com/gfx-rs/naga"
-tag = "gfx-7"
+tag = "gfx-8"
 features = ["spv-in", "spv-out", "wgsl-in"]
 
 [dependencies.wgt]
diff --git a/wgpu-core/src/command/allocator.rs b/wgpu-core/src/command/allocator.rs
index df30faa6a8..f00c5d9eda 100644
--- a/wgpu-core/src/command/allocator.rs
+++ b/wgpu-core/src/command/allocator.rs
@@ -62,6 +62,13 @@ impl<B: hal::Backend> CommandPool<B> {
         }
         self.available.pop().unwrap()
     }
+
+    fn destroy(mut self, device: &B::Device) {
+        unsafe {
+            self.raw.free(self.available.into_iter());
+            device.destroy_command_pool(self.raw);
+        }
+    }
 }
 
 #[derive(Debug)]
@@ -237,11 +244,8 @@ impl<B: hal::Backend> CommandAllocator<B> {
         }
         for thread_id in remove_threads {
             tracing::info!("Removing from thread {:?}", thread_id);
-            let mut pool = inner.pools.remove(&thread_id).unwrap();
-            unsafe {
-                pool.raw.free(pool.available);
-                device.destroy_command_pool(pool.raw);
-            }
+            let pool = inner.pools.remove(&thread_id).unwrap();
+            pool.destroy(device);
         }
     }
 
@@ -258,10 +262,7 @@ impl<B: hal::Backend> CommandAllocator<B> {
                     pool.total
                 );
             }
-            unsafe {
-                pool.raw.free(pool.available);
-                device.destroy_command_pool(pool.raw);
-            }
+            pool.destroy(device);
         }
     }
 }
diff --git a/wgpu-core/src/command/compute.rs b/wgpu-core/src/command/compute.rs
index f137bb86ba..a1399f8e75 100644
--- a/wgpu-core/src/command/compute.rs
+++ b/wgpu-core/src/command/compute.rs
@@ -15,10 +15,9 @@ use crate::{
     span,
     track::{TrackerSet, UsageConflict},
     validation::{check_buffer_usage, MissingBufferUsageError},
-    Label, MAX_BIND_GROUPS,
+    Label,
 };
 
-use arrayvec::ArrayVec;
 use hal::command::CommandBuffer as _;
 use thiserror::Error;
 use wgt::{BufferAddress, BufferUsage, ShaderStage};
@@ -330,13 +329,11 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                         bind_group,
                         &temp_offsets,
                     ) {
-                        let bind_groups = iter::once(bind_group.raw.raw())
-                            .chain(
-                                follow_ups
-                                    .clone()
-                                    .map(|(bg_id, _)| bind_group_guard[bg_id].raw.raw()),
-                            )
-                            .collect::<ArrayVec<[_; MAX_BIND_GROUPS]>>();
+                        let bind_groups = iter::once(bind_group.raw.raw()).chain(
+                            follow_ups
+                                .clone()
+                                .map(|(bg_id, _)| bind_group_guard[bg_id].raw.raw()),
+                        );
                         temp_offsets.extend(follow_ups.flat_map(|(_, offsets)| offsets));
                         unsafe {
                             raw.bind_compute_descriptor_sets(
diff --git a/wgpu-core/src/command/render.rs b/wgpu-core/src/command/render.rs
index c9ff83af15..bf3ff2e3b9 100644
--- a/wgpu-core/src/command/render.rs
+++ b/wgpu-core/src/command/render.rs
@@ -24,7 +24,7 @@ use crate::{
     validation::{
         check_buffer_usage, check_texture_usage, MissingBufferUsageError, MissingTextureUsageError,
     },
-    Label, Stored, MAX_BIND_GROUPS,
+    Label, Stored,
 };
 
 use arrayvec::ArrayVec;
@@ -802,11 +802,7 @@ impl<'a, B: GfxBackend> RenderPassInfo<'a, B> {
                     inputs: &[],
                     preserves: &[],
                 };
-                let all = entry
-                    .key()
-                    .all()
-                    .map(|(at, _)| at.clone())
-                    .collect::<AttachmentDataVec<_>>();
+                let all = entry.key().all().map(|(at, _)| at.clone());
 
                 let pass = unsafe {
                     device
@@ -1127,13 +1123,11 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                             bind_group,
                             &temp_offsets,
                         ) {
-                            let bind_groups = iter::once(bind_group.raw.raw())
-                                .chain(
-                                    follow_ups
-                                        .clone()
-                                        .map(|(bg_id, _)| bind_group_guard[bg_id].raw.raw()),
-                                )
-                                .collect::<ArrayVec<[_; MAX_BIND_GROUPS]>>();
+                            let bind_groups = iter::once(bind_group.raw.raw()).chain(
+                                follow_ups
+                                    .clone()
+                                    .map(|(bg_id, _)| bind_group_guard[bg_id].raw.raw()),
+                            );
                             temp_offsets.extend(follow_ups.flat_map(|(_, offsets)| offsets));
                             unsafe {
                                 raw.bind_graphics_descriptor_sets(
diff --git a/wgpu-core/src/command/transfer.rs b/wgpu-core/src/command/transfer.rs
index a226c9ef15..e19fcd3a87 100644
--- a/wgpu-core/src/command/transfer.rs
+++ b/wgpu-core/src/command/transfer.rs
@@ -319,9 +319,6 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         let (mut cmd_buf_guard, mut token) = hub.command_buffers.write(&mut token);
         let cmd_buf = CommandBuffer::get_encoder_mut(&mut *cmd_buf_guard, command_encoder_id)?;
         let (buffer_guard, _) = hub.buffers.read(&mut token);
-        // we can't hold both src_pending and dst_pending in scope because they
-        // borrow the buffer tracker mutably...
-        let mut barriers = Vec::new();
 
         #[cfg(feature = "trace")]
         if let Some(ref mut list) = cmd_buf.commands {
@@ -346,7 +343,10 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         if !src_buffer.usage.contains(BufferUsage::COPY_SRC) {
             Err(TransferError::MissingCopySrcUsageFlag)?
         }
-        barriers.extend(src_pending.map(|pending| pending.into_hal(src_buffer)));
+        // expecting only a single barrier
+        let src_barrier = src_pending
+            .map(|pending| pending.into_hal(src_buffer))
+            .next();
 
         let (dst_buffer, dst_pending) = cmd_buf
             .trackers
@@ -363,7 +363,9 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                 None,
             ))?
         }
-        barriers.extend(dst_pending.map(|pending| pending.into_hal(dst_buffer)));
+        let dst_barrier = dst_pending
+            .map(|pending| pending.into_hal(dst_buffer))
+            .next();
 
         if size % wgt::COPY_BUFFER_ALIGNMENT != 0 {
             Err(TransferError::UnalignedCopySize(size))?
@@ -409,7 +411,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
             cmd_buf_raw.pipeline_barrier(
                 all_buffer_stages()..hal::pso::PipelineStage::TRANSFER,
                 hal::memory::Dependencies::empty(),
-                barriers,
+                src_barrier.into_iter().chain(dst_barrier),
             );
             cmd_buf_raw.copy_buffer(src_raw, dst_raw, iter::once(region));
         }
@@ -713,9 +715,6 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         let cmd_buf = CommandBuffer::get_encoder_mut(&mut *cmd_buf_guard, command_encoder_id)?;
         let (_, mut token) = hub.buffers.read(&mut token); // skip token
         let (texture_guard, _) = hub.textures.read(&mut token);
-        // we can't hold both src_pending and dst_pending in scope because they
-        // borrow the buffer tracker mutably...
-        let mut barriers = Vec::new();
         let (src_layers, src_selector, src_offset) =
             texture_copy_view_to_hal(source, copy_size, &*texture_guard)?;
         let (dst_layers, dst_selector, dst_offset) =
@@ -755,7 +754,11 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
         if !src_texture.usage.contains(TextureUsage::COPY_SRC) {
             Err(TransferError::MissingCopySrcUsageFlag)?
         }
-        barriers.extend(src_pending.map(|pending| pending.into_hal(src_texture)));
+        //TODO: try to avoid this the collection. It's needed because both
+        // `src_pending` and `dst_pending` try to hold `trackers.textures` mutably.
+        let mut barriers = src_pending
+            .map(|pending| pending.into_hal(src_texture))
+            .collect::<Vec<_>>();
 
         let (dst_texture, dst_pending) = cmd_buf
             .trackers
@@ -822,7 +825,7 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
             cmd_buf_raw.pipeline_barrier(
                 all_image_stages()..hal::pso::PipelineStage::TRANSFER,
                 hal::memory::Dependencies::empty(),
-                barriers,
+                barriers.into_iter(),
             );
             cmd_buf_raw.copy_image(
                 src_raw,
diff --git a/wgpu-core/src/device/descriptor.rs b/wgpu-core/src/device/descriptor.rs
index 3b350233eb..3f21a44d8b 100644
--- a/wgpu-core/src/device/descriptor.rs
+++ b/wgpu-core/src/device/descriptor.rs
@@ -121,7 +121,7 @@ impl<B: hal::Backend>
         match hal::device::Device::create_descriptor_pool(
             self.0,
             max_sets as usize,
-            ranges,
+            ranges.into_iter(),
             hal::pso::DescriptorPoolCreateFlags::from_bits_truncate(flags.bits()),
         ) {
             Ok(pool) => Ok(pool),
diff --git a/wgpu-core/src/device/mod.rs b/wgpu-core/src/device/mod.rs
index 0103a76b01..1a2fcc733c 100644
--- a/wgpu-core/src/device/mod.rs
+++ b/wgpu-core/src/device/mod.rs
@@ -1066,10 +1066,7 @@ impl<B: GfxBackend> Device<B> {
             resolves: &[],
             preserves: &[],
         };
-        let all = key
-            .all()
-            .map(|(at, _)| at.clone())
-            .collect::<AttachmentDataVec<_>>();
+        let all = key.all().map(|(at, _)| at.clone());
 
         unsafe {
             self.raw
@@ -1169,7 +1166,7 @@ impl<B: GfxBackend> Device<B> {
         let raw = unsafe {
             let mut raw_layout = self
                 .raw
-                .create_descriptor_set_layout(raw_bindings, &[])
+                .create_descriptor_set_layout(raw_bindings, iter::empty())
                 .or(Err(DeviceError::OutOfMemory))?;
             if let Some(label) = label {
                 self.raw
@@ -1526,10 +1523,7 @@ impl<B: GfxBackend> Device<B> {
         }
 
         if let Some(start_binding) = write_map.keys().next().cloned() {
-            let descriptors = write_map
-                .into_iter()
-                .flat_map(|(_, list)| list)
-                .collect::<Vec<_>>();
+            let descriptors = write_map.into_iter().flat_map(|(_, list)| list);
             unsafe {
                 let write = hal::pso::DescriptorSetWrite {
                     set: desc_set.raw_mut(),
diff --git a/wgpu-core/src/device/queue.rs b/wgpu-core/src/device/queue.rs
index d51ed3f555..dbc53f28a4 100644
--- a/wgpu-core/src/device/queue.rs
+++ b/wgpu-core/src/device/queue.rs
@@ -619,14 +619,11 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
                     .raw
                     .create_fence(false)
                     .or(Err(DeviceError::OutOfMemory))?;
-                let mut command_buffers = pending_write_command_buffer
-                    .as_ref()
-                    .into_iter()
-                    .collect::<Vec<_>>();
-                for &cmd_buf_id in command_buffer_ids {
-                    let cmd_buf = command_buffer_guard.get(cmd_buf_id).unwrap();
-                    command_buffers.extend(cmd_buf.raw.iter());
-                }
+                let command_buffers = pending_write_command_buffer.as_ref().into_iter().chain(
+                    command_buffer_ids.iter().flat_map(|&cmd_buf_id| {
+                        command_buffer_guard.get(cmd_buf_id).unwrap().raw.iter()
+                    }),
+                );
                 let signal_semaphores = signal_swapchain_semaphores
                     .into_iter()
                     .map(|sc_id| &swap_chain_guard[sc_id].semaphore);