Allow legacy custom derive authors to disable warnings in downstream crates.

2 files changed, 6 insertions, 0 deletions

diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index f73227681c5..fa9e67bb40a 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -1111,6 +1111,7 @@ pub struct Resolver<'a> {
     lexical_macro_resolutions: Vec<(Name, &'a Cell<LegacyScope<'a>>)>,
     macro_map: FxHashMap<DefId, Rc<SyntaxExtension>>,
     macro_exports: Vec<Export>,
+    pub whitelisted_legacy_custom_derives: Vec<Name>,
 
     // Maps the `Mark` of an expansion to its containing module or block.
     invocations: FxHashMap<Mark, &'a InvocationData<'a>>,
@@ -1292,6 +1293,7 @@ impl<'a> Resolver<'a> {
             macro_exports: Vec::new(),
             invocations: invocations,
             name_already_seen: FxHashMap(),
+            whitelisted_legacy_custom_derives: Vec::new(),
         }
     }
 
diff --git a/src/librustc_resolve/macros.rs b/src/librustc_resolve/macros.rs
index 204d1127fc4..cdff84c8b8a 100644
--- a/src/librustc_resolve/macros.rs
+++ b/src/librustc_resolve/macros.rs
@@ -123,6 +123,10 @@ impl<'a> base::Resolver for Resolver<'a> {
         EliminateCrateVar(self).fold_item(item).expect_one("")
     }
 
+    fn is_whitelisted_legacy_custom_derive(&self, name: Name) -> bool {
+        self.whitelisted_legacy_custom_derives.contains(&name)
+    }
+
     fn visit_expansion(&mut self, mark: Mark, expansion: &Expansion) {
         let invocation = self.invocations[&mark];
         self.collect_def_ids(invocation, expansion);