pretty print hir attributes

compiler/rustc_macros/src/lib.rs

@@ -17,6 +17,7 @@ mod diagnostics;
 mod extension;
 mod hash_stable;
 mod lift;
+mod print_attribute;
 mod query;
 mod serialize;
 mod symbols;
@@ -175,3 +176,11 @@ decl_derive! {
     /// The error type is `u32`.
     try_from::try_from_u32
 }
+decl_derive! {
+    [PrintAttribute] =>
+    /// Derives `PrintAttribute` for `AttributeKind`.
+    /// This macro is pretty specific to `rustc_attr_data_structures` and likely not that useful in
+    /// other places. It's deriving something close to `Debug` without printing some extraenous
+    /// things like spans.
+    print_attribute::print_attribute
+}