Port #[rustc_pass_by_value] to the new attribute system

compiler/rustc_attr_data_structures/src/attributes.rs

@@ -284,6 +284,9 @@ pub enum AttributeKind {
     /// Represents `#[optimize(size|speed)]`
     Optimize(OptimizeAttr, Span),
 
+    /// Represents `#[rustc_pass_by_value]` (used by the `rustc_pass_by_value` lint).
+    PassByValue(Span),
+
     /// Represents `#[rustc_pub_transparent]` (used by the `repr_transparent_external_private_fields` lint).
     PubTransparent(Span),
 

compiler/rustc_attr_data_structures/src/encode_cross_crate.rs

@@ -36,6 +36,7 @@ impl AttributeKind {
             Naked(..) => No,
             NoMangle(..) => No,
             Optimize(..) => No,
+            PassByValue(..) => Yes,
             PubTransparent(..) => Yes,
             Repr(..) => No,
             RustcLayoutScalarValidRangeEnd(..) => Yes,