Fix serde feature gating

Author: andyleiserson

wgpu-core/src/command/compute_command.rs

@@ -1,4 +1,6 @@
-use crate::command::{serde_object_reference_struct, ArcReferences, ReferenceType};
+#[cfg(feature = "serde")]
+use crate::command::serde_object_reference_struct;
+use crate::command::{ArcReferences, ReferenceType};
 
 #[cfg(feature = "serde")]
 use macro_rules_attribute::apply;

wgpu-core/src/command/encoder_command.rs

@@ -35,6 +35,7 @@ pub struct IdReferences;
 /// This is used for trace recording and playback. Recording stores the pointer
 /// value of `Arc` references in the trace. Playback uses the integer values
 /// as keys to a `HashMap`.
+#[cfg(feature = "serde")]
 #[doc(hidden)]
 #[derive(Clone, Debug)]
 pub struct PointerReferences;
@@ -58,6 +59,7 @@ impl ReferenceType for IdReferences {
     type Tlas = id::TlasId;
 }
 
+#[cfg(feature = "serde")]
 impl ReferenceType for PointerReferences {
     type Buffer = id::PointerId<id::markers::Buffer>;
     type Surface = id::PointerId<id::markers::Surface>;

wgpu-core/src/command/render_command.rs

@@ -1,7 +1,9 @@
 use wgt::{BufferAddress, BufferSize, Color};
 
 use super::{DrawCommandFamily, Rect};
-use crate::command::{serde_object_reference_struct, ArcReferences, ReferenceType};
+#[cfg(feature = "serde")]
+use crate::command::serde_object_reference_struct;
+use crate::command::{ArcReferences, ReferenceType};
 
 #[cfg(feature = "serde")]
 use macro_rules_attribute::apply;

wgpu-core/src/id.rs

@@ -96,21 +96,25 @@ pub enum SerialId {
     Id(Index, Epoch),
 }
 
+#[cfg(feature = "serde")]
 impl From<RawId> for SerialId {
     fn from(id: RawId) -> Self {
         let (index, epoch) = id.unzip();
         Self::Id(index, epoch)
     }
 }
 
+#[cfg(feature = "serde")]
 pub struct ZeroIdError;
 
+#[cfg(feature = "serde")]
 impl fmt::Display for ZeroIdError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "IDs may not be zero")
     }
 }
 
+#[cfg(feature = "serde")]
 impl TryFrom<SerialId> for RawId {
     type Error = ZeroIdError;
     fn try_from(id: SerialId) -> Result<Self, ZeroIdError> {
@@ -127,21 +131,24 @@ impl TryFrom<SerialId> for RawId {
 ///
 /// This is used for tracing.
 #[allow(dead_code)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
-#[derive(Debug)]
+#[cfg(feature = "serde")]
+#[derive(Debug, serde::Serialize, serde::Deserialize)]
 pub enum PointerId<T: Marker> {
     // The only variant forces RON to not ignore "Id"
     PointerId(usize, #[serde(skip)] PhantomData<T>),
 }
 
+#[cfg(feature = "serde")]
 impl<T: Marker> Copy for PointerId<T> {}
 
+#[cfg(feature = "serde")]
 impl<T: Marker> Clone for PointerId<T> {
     fn clone(&self) -> Self {
         *self
     }
 }
 
+#[cfg(feature = "serde")]
 impl<T: Marker> PartialEq for PointerId<T> {
     fn eq(&self, other: &Self) -> bool {
         let PointerId::PointerId(this, _) = self;
@@ -150,15 +157,18 @@ impl<T: Marker> PartialEq for PointerId<T> {
     }
 }
 
+#[cfg(feature = "serde")]
 impl<T: Marker> Eq for PointerId<T> {}
 
+#[cfg(feature = "serde")]
 impl<T: Marker> Hash for PointerId<T> {
     fn hash<H: core::hash::Hasher>(&self, state: &mut H) {
         let PointerId::PointerId(this, _) = self;
         this.hash(state);
     }
 }
 
+#[cfg(feature = "serde")]
 impl<T: StorageItem> From<&Arc<T>> for PointerId<T::Marker> {
     fn from(arc: &Arc<T>) -> Self {
         // Since the memory representation of `Arc<T>` is just a pointer to