6 files changed, 19 insertions, 15 deletions
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index 96d19e8e17d..3ca02b61063 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -123,7 +123,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                     attrs: Default::default(),
                     visibility: Inherited,
                     def_id: self.cx.next_def_id(param_env_def_id.krate),
-                    kind: ImplItem(Impl {
+                    kind: box ImplItem(Impl {
                         unsafety: hir::Unsafety::Normal,
                         generics: new_generics,
                         provided_trait_methods: Default::default(),
diff --git a/src/librustdoc/clean/blanket_impl.rs b/src/librustdoc/clean/blanket_impl.rs
index d99055e1145..ba3eb007e38 100644
--- a/src/librustdoc/clean/blanket_impl.rs
+++ b/src/librustdoc/clean/blanket_impl.rs
@@ -112,7 +112,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                     attrs: Default::default(),
                     visibility: Inherited,
                     def_id: self.cx.next_def_id(impl_def_id.krate),
-                    kind: ImplItem(Impl {
+                    kind: box ImplItem(Impl {
                         unsafety: hir::Unsafety::Normal,
                         generics: (
                             self.cx.tcx.generics_of(impl_def_id),
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index be4c62d891d..c168c56d30d 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -482,7 +482,7 @@ fn build_module(cx: &DocContext<'_>, did: DefId, visited: &mut FxHashSet<DefId>)
                         source: clean::Span::dummy(),
                         def_id: DefId::local(CRATE_DEF_INDEX),
                         visibility: clean::Public,
-                        kind: clean::ImportItem(clean::Import::new_simple(
+                        kind: box clean::ImportItem(clean::Import::new_simple(
                             item.ident.name,
                             clean::ImportSource {
                                 path: clean::Path {
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index dd96178cdb7..a2a0ad1844f 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -2160,7 +2160,7 @@ fn clean_extern_crate(
         source: krate.span.clean(cx),
         def_id: crate_def_id,
         visibility: krate.vis.clean(cx),
-        kind: ExternCrateItem(name, orig_name),
+        kind: box ExternCrateItem(name, orig_name),
     }]
 }
 
@@ -2228,7 +2228,7 @@ impl Clean<Vec<Item>> for doctree::Import<'_> {
                         source: self.span.clean(cx),
                         def_id: cx.tcx.hir().local_def_id(self.id).to_def_id(),
                         visibility: self.vis.clean(cx),
-                        kind: ImportItem(Import::new_simple(
+                        kind: box ImportItem(Import::new_simple(
                             self.name,
                             resolve_use_source(cx, path),
                             false,
@@ -2246,7 +2246,7 @@ impl Clean<Vec<Item>> for doctree::Import<'_> {
             source: self.span.clean(cx),
             def_id: cx.tcx.hir().local_def_id(self.id).to_def_id(),
             visibility: self.vis.clean(cx),
-            kind: ImportItem(inner),
+            kind: box ImportItem(inner),
         }]
     }
 }
diff --git a/src/librustdoc/clean/types.rs b/src/librustdoc/clean/types.rs
index dd818a643ef..0f2baa90b51 100644
--- a/src/librustdoc/clean/types.rs
+++ b/src/librustdoc/clean/types.rs
@@ -84,10 +84,14 @@ crate struct Item {
     crate name: Option<Symbol>,
     crate attrs: Attributes,
     crate visibility: Visibility,
-    crate kind: ItemKind,
+    crate kind: Box<ItemKind>,
     crate def_id: DefId,
 }
 
+// `Item` is used a lot. Make sure it doesn't unintentionally get bigger.
+#[cfg(target_arch = "x86_64")]
+rustc_data_structures::static_assert_size!(Item, 136);
+
 impl fmt::Debug for Item {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
         let def_id: &dyn fmt::Debug = if self.is_fake() { &"**FAKE**" } else { &self.def_id };
@@ -152,7 +156,7 @@ impl Item {
 
         Item {
             def_id,
-            kind,
+            kind: box kind,
             name,
             source: source.clean(cx),
             attrs: cx.tcx.get_attrs(def_id).clean(cx),
@@ -171,7 +175,7 @@ impl Item {
     }
 
     crate fn is_crate(&self) -> bool {
-        match self.kind {
+        match *self.kind {
             StrippedItem(box ModuleItem(Module { is_crate: true, .. }))
             | ModuleItem(Module { is_crate: true, .. }) => true,
             _ => false,
@@ -223,14 +227,14 @@ impl Item {
         self.type_() == ItemType::Keyword
     }
     crate fn is_stripped(&self) -> bool {
-        match self.kind {
+        match *self.kind {
             StrippedItem(..) => true,
             ImportItem(ref i) => !i.should_be_displayed,
             _ => false,
         }
     }
     crate fn has_stripped_fields(&self) -> Option<bool> {
-        match self.kind {
+        match *self.kind {
             StructItem(ref _struct) => Some(_struct.fields_stripped),
             UnionItem(ref union) => Some(union.fields_stripped),
             VariantItem(Variant { kind: VariantKind::Struct(ref vstruct) }) => {
@@ -281,7 +285,7 @@ impl Item {
     }
 
     crate fn is_default(&self) -> bool {
-        match self.kind {
+        match *self.kind {
             ItemKind::MethodItem(_, Some(defaultness)) => {
                 defaultness.has_value() && !defaultness.is_final()
             }
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index 270321aaa11..2e479d25203 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -43,7 +43,7 @@ crate fn krate(mut cx: &mut DocContext<'_>) -> Crate {
     let mut module = module.clean(cx);
     let mut masked_crates = FxHashSet::default();
 
-    match module.kind {
+    match *module.kind {
         ItemKind::ModuleItem(ref module) => {
             for it in &module.items {
                 // `compiler_builtins` should be masked too, but we can't apply
@@ -61,7 +61,7 @@ crate fn krate(mut cx: &mut DocContext<'_>) -> Crate {
 
     let ExternalCrate { name, src, primitives, keywords, .. } = LOCAL_CRATE.clean(cx);
     {
-        let m = match module.kind {
+        let m = match *module.kind {
             ItemKind::ModuleItem(ref mut m) => m,
             _ => unreachable!(),
         };
@@ -338,7 +338,7 @@ crate fn build_deref_target_impls(cx: &DocContext<'_>, items: &[Item], ret: &mut
     let tcx = cx.tcx;
 
     for item in items {
-        let target = match item.kind {
+        let target = match *item.kind {
             ItemKind::TypedefItem(ref t, true) => &t.type_,
             _ => continue,
         };