Keep encoding attributes for closures

Author: oli-obk

compiler/rustc_metadata/src/rmeta/encoder.rs

@@ -862,6 +862,11 @@ fn should_encode_attrs(def_kind: DefKind) -> bool {
         | DefKind::Macro(_)
         | DefKind::Field
         | DefKind::Impl { .. } => true,
+        // Tools may want to be able to detect their tool lints on
+        // closures from upstream crates, too. This is used by
+        // https://github.com/model-checking/kani and is not a performance
+        // or maintenance issue for us.
+        DefKind::Closure => true,
         DefKind::TyParam
         | DefKind::ConstParam
         | DefKind::Ctor(..)
@@ -874,7 +879,6 @@ fn should_encode_attrs(def_kind: DefKind) -> bool {
         | DefKind::ImplTraitPlaceholder
         | DefKind::LifetimeParam
         | DefKind::GlobalAsm
-        | DefKind::Closure
         | DefKind::Generator => false,
     }
 }