Remove #[derive(Clone)] from our OOM-handling Vec<T> (#12668)

If the `Vec<T>` is non-empty, then cloning will allocate, so we should only
implement `TryClone`, not `Clone`.

Author: fitzgen

crates/core/src/alloc/vec.rs

@@ -49,7 +49,7 @@ macro_rules! private_len {
 
 /// Like `std::vec::Vec` but all methods that allocate force handling allocation
 /// failure.
-#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+#[derive(PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct Vec<T> {
     inner: StdVec<T>,
 }

crates/environ/src/gc.rs

@@ -370,7 +370,7 @@ impl GcArrayLayout {
 /// tuples of typed fields with a certain size. The only difference in
 /// practice is that an exception object also carries a tag reference
 /// (at a fixed offset as per `GcTypeLayouts::exception_tag_offset`).
-#[derive(Clone, Debug)]
+#[derive(Debug)]
 pub struct GcStructLayout {
     /// The size (in bytes) of this struct.
     pub size: u32,

crates/environ/src/module.rs

@@ -237,7 +237,7 @@ pub struct TableInitialization {
 }
 
 /// Initial value for all elements in a table.
-#[derive(Clone, Debug, Serialize, Deserialize)]
+#[derive(Debug, Serialize, Deserialize)]
 pub enum TableInitialValue {
     /// Initialize each table element to null, optionally setting some elements
     /// to non-null given the precomputed image.