diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 58f584d65d58..2a3b50c79bba 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -522,6 +522,7 @@ rustc_queries! {
     }
     query adt_def(key: DefId) -> &'tcx ty::AdtDef {
         desc { |tcx| "computing ADT definition for `{}`", tcx.def_path_str(key) }
+        cache_on_disk_if { true }
         separate_provide_extern
     }
     query adt_destructor(key: DefId) -> Option<ty::Destructor> {
diff --git a/compiler/rustc_middle/src/ty/codec.rs b/compiler/rustc_middle/src/ty/codec.rs
index 2032f32ed8c2..3a8a3c0b1649 100644
--- a/compiler/rustc_middle/src/ty/codec.rs
+++ b/compiler/rustc_middle/src/ty/codec.rs
@@ -155,7 +155,8 @@ encodable_via_deref! {
     &'tcx mir::Body<'tcx>,
     &'tcx mir::UnsafetyCheckResult,
     &'tcx mir::BorrowCheckResult<'tcx>,
-    &'tcx mir::coverage::CodeRegion
+    &'tcx mir::coverage::CodeRegion,
+    &'tcx ty::AdtDef
 }
 
 pub trait TyDecoder<'tcx>: Decoder {
@@ -391,7 +392,8 @@ impl_decodable_via_ref! {
     &'tcx mir::UnsafetyCheckResult,
     &'tcx mir::BorrowCheckResult<'tcx>,
     &'tcx mir::coverage::CodeRegion,
-    &'tcx ty::List<ty::BoundVariableKind>
+    &'tcx ty::List<ty::BoundVariableKind>,
+    &'tcx ty::AdtDef
 }
 
 #[macro_export]