Hide Clone implementations behind crate feature

Cargo.toml

@@ -23,6 +23,7 @@ panic = "abort"
 
 [features]
 default = []
+clone = []
 dot-out = []
 glsl-in = ["pp-rs"]
 glsl-validate = []

src/arena.rs

@@ -161,7 +161,7 @@ impl<T> Iterator for Range<T> {
 /// Adding new items to the arena produces a strongly-typed [`Handle`].
 /// The arena can be indexed using the given handle to obtain
 /// a reference to the stored item.
-#[derive(Clone)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(serde::Serialize))]
 #[cfg_attr(feature = "serialize", serde(transparent))]
 #[cfg_attr(feature = "arbitrary", derive(arbitrary::Arbitrary))]
@@ -413,7 +413,7 @@ mod tests {
 ///
 /// `UniqueArena` is similar to [`Arena`]: If `Arena` is vector-like,
 /// `UniqueArena` is `HashSet`-like.
-#[derive(Clone)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 pub struct UniqueArena<T> {
     set: IndexSet<T>,
 

src/lib.rs

@@ -34,6 +34,9 @@ with optional span info, representing a series of statements executed in order.
 `EntryPoint`s or `Function` is a `Block`, and `Statement` has a
 [`Block`][Statement::Block] variant.
 
+If the `clone` feature is enabled, [`Arena`], [`UniqueArena`], [`Type`], [`TypeInner`],
+[`Constant`], [`Function`], [`EntryPoint`] and [`Module`] can be cloned.
+
 ## Arenas
 
 To improve translator performance and reduce memory usage, most structures are
@@ -556,7 +559,8 @@ pub enum ImageClass {
 }
 
 /// A data type declared in the module.
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(Serialize))]
 #[cfg_attr(feature = "deserialize", derive(Deserialize))]
 #[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
@@ -568,7 +572,8 @@ pub struct Type {
 }
 
 /// Enum with additional information, depending on the kind of type.
-#[derive(Clone, Debug, Eq, Hash, PartialEq)]
+#[derive(Debug, Eq, Hash, PartialEq)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(Serialize))]
 #[cfg_attr(feature = "deserialize", derive(Deserialize))]
 #[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
@@ -744,7 +749,8 @@ pub enum TypeInner {
 }
 
 /// Constant value.
-#[derive(Clone, Debug, PartialEq)]
+#[derive(Debug, PartialEq)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(Serialize))]
 #[cfg_attr(feature = "deserialize", derive(Deserialize))]
 #[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
@@ -1582,7 +1588,8 @@ pub struct FunctionResult {
 }
 
 /// A function defined in the module.
-#[derive(Clone, Debug, Default)]
+#[derive(Debug, Default)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(Serialize))]
 #[cfg_attr(feature = "deserialize", derive(Deserialize))]
 #[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
@@ -1646,7 +1653,8 @@ pub struct Function {
 /// [`Location`]: Binding::Location
 /// [`function`]: EntryPoint::function
 /// [`stage`]: EntryPoint::stage
-#[derive(Clone, Debug)]
+#[derive(Debug)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(Serialize))]
 #[cfg_attr(feature = "deserialize", derive(Deserialize))]
 #[cfg_attr(feature = "arbitrary", derive(Arbitrary))]
@@ -1676,7 +1684,8 @@ pub struct EntryPoint {
 /// Alternatively, you can load an existing shader using one of the [available front ends][front].
 ///
 /// When finished, you can export modules using one of the [available backends][back].
-#[derive(Clone, Debug, Default)]
+#[derive(Debug, Default)]
+#[cfg_attr(feature = "clone", derive(Clone))]
 #[cfg_attr(feature = "serialize", derive(Serialize))]
 #[cfg_attr(feature = "deserialize", derive(Deserialize))]
 #[cfg_attr(feature = "arbitrary", derive(Arbitrary))]