Document what feature everything requires
diff --git a/src/op.rs b/src/op.rs
index c0873a2..b9a8ef7 100644
--- a/src/op.rs
+++ b/src/op.rs
@@ -8,6 +8,9 @@
ast_enum! {
/// A binary operator: `+`, `+=`, `&`.
+ ///
+ /// *This type is available if Syn is built with the `"derive"` or `"full"`
+ /// feature.*
#[cfg_attr(feature = "clone-impls", derive(Copy))]
pub enum BinOp {
/// The `+` operator (addition)
@@ -71,6 +74,9 @@
ast_enum! {
/// A unary operator: `*`, `!`, `-`.
+ ///
+ /// *This type is available if Syn is built with the `"derive"` or `"full"`
+ /// feature.*
#[cfg_attr(feature = "clone-impls", derive(Copy))]
pub enum UnOp {
/// The `*` operator for dereferencing