polymorphize: polymorphize shims

This commit removes the restriction of `InstanceDef::Item` on
polymorphization, so that shims can now be polymorphized.

Signed-off-by: David Wood <david.wood@huawei.com>

2 files changed, 9 insertions, 1 deletions

diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index bd1d99640f8..79f1beb0799 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -84,6 +84,12 @@ impl IntoArgs for (CrateNum, DefId) {
     }
 }
 
+impl IntoArgs for ty::InstanceDef<'tcx> {
+    fn into_args(self) -> (DefId, DefId) {
+        (self.def_id(), self.def_id())
+    }
+}
+
 provide! { <'tcx> tcx, def_id, other, cdata,
     type_of => { cdata.get_type(def_id.index, tcx) }
     generics_of => { cdata.get_generics(def_id.index, tcx.sess) }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 1e3bf8aca8b..8947c13430f 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -1320,7 +1320,9 @@ impl EncodeContext<'a, 'tcx> {
             }
             record!(self.tables.promoted_mir[def_id.to_def_id()] <- self.tcx.promoted_mir(def_id));
 
-            let unused = self.tcx.unused_generic_params(def_id);
+            let instance =
+                ty::InstanceDef::Item(ty::WithOptConstParam::unknown(def_id.to_def_id()));
+            let unused = self.tcx.unused_generic_params(instance);
             if !unused.is_empty() {
                 record!(self.tables.unused_generic_params[def_id.to_def_id()] <- unused);
             }