Merge branch 'port_on_unimplemented' of https://github.com/mejrs/rust into port_on_unimplemented

Author: mejrs

compiler/rustc_hir/src/attrs/data_structures.rs

@@ -947,6 +947,13 @@ pub enum AttributeKind {
         directive: Option<Box<OnUnimplementedDirective>>,
     },
 
+    /// Represents `#[rustc_on_unimplemented]` and `#[diagnostic::on_unimplemented]`.
+    OnUnimplemented {
+        span: Span,
+        /// None if the directive was malformed in some way.
+        directive: Option<Box<OnUnimplementedDirective>>,
+    },
+
     /// Represents `#[optimize(size|speed)]`
     Optimize(OptimizeAttr, Span),