Queryify check_impl_item_well_formed

Fixes rust-lang#46753

src/librustc/dep_graph/dep_node.rs

@@ -581,6 +581,7 @@ define_dep_nodes!( <'tcx>
     [] ImplDefaultness(DefId),
     [] CheckItemWellFormed(DefId),
     [] CheckTraitItemWellFormed(DefId),
+    [] CheckImplItemWellFormed(DefId),
     [] ReachableNonGenerics(CrateNum),
     [] NativeLibraries(CrateNum),
     [] PluginRegistrarFn(CrateNum),

src/librustc/ty/maps/mod.rs

@@ -300,6 +300,7 @@ define_maps! { <'tcx>
 
     [] fn check_item_well_formed: CheckItemWellFormed(DefId) -> (),
     [] fn check_trait_item_well_formed: CheckTraitItemWellFormed(DefId) -> (),
+    [] fn check_impl_item_well_formed: CheckImplItemWellFormed(DefId) -> (),
 
     // The DefIds of all non-generic functions and statics in the given crate
     // that can be reached from outside the crate.

src/librustc/ty/maps/plumbing.rs

@@ -873,6 +873,7 @@ pub fn force_from_dep_node<'a, 'gcx, 'lcx>(tcx: TyCtxt<'a, 'gcx, 'lcx>,
         DepKind::ImplDefaultness => { force!(impl_defaultness, def_id!()); }
         DepKind::CheckItemWellFormed => { force!(check_item_well_formed, def_id!()); }
         DepKind::CheckTraitItemWellFormed => { force!(check_trait_item_well_formed, def_id!()); }
+        DepKind::CheckImplItemWellFormed => { force!(check_impl_item_well_formed, def_id!()); }
         DepKind::ReachableNonGenerics => { force!(reachable_non_generics, krate!()); }
         DepKind::NativeLibraries => { force!(native_libraries, krate!()); }
         DepKind::PluginRegistrarFn => { force!(plugin_registrar_fn, krate!()); }

src/librustc_typeck/check/mod.rs

@@ -726,6 +726,10 @@ fn check_trait_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: D
     wfcheck::CheckTypeWellFormed::new(tcx).check_trait_item(def_id);
 }
 
+fn check_impl_item_well_formed<'a, 'tcx>(tcx: TyCtxt<'a, 'tcx, 'tcx>, def_id: DefId) {
+    wfcheck::CheckTypeWellFormed::new(tcx).check_impl_item(def_id);
+}
+
 pub fn provide(providers: &mut Providers) {
     *providers = Providers {
         typeck_item_bodies,
@@ -735,6 +739,7 @@ pub fn provide(providers: &mut Providers) {
         used_trait_imports,
         check_item_well_formed,
         check_trait_item_well_formed,
+        check_impl_item_well_formed,
         ..*providers
     };
 }

src/librustc_typeck/check/wfcheck.rs

@@ -171,6 +171,17 @@ impl<'a, 'gcx> CheckTypeWellFormed<'a, 'gcx> {
             .check_associated_item(trait_item.id, trait_item.span, method_sig);
     }
 
+    pub fn check_impl_item(&mut self, def_id: DefId) {
+        let node_id = self.tcx.hir.as_local_node_id(def_id).unwrap();
+        let impl_item = self.tcx.hir.expect_impl_item(node_id);
+
+        let method_sig = match impl_item.node {
+            hir::ImplItemKind::Method(ref sig, _) => Some(sig),
+            _ => None
+        };
+        self.check_associated_item(impl_item.id, impl_item.span, method_sig);
+    }
+
     fn check_associated_item(&mut self,
                              item_id: ast::NodeId,
                              span: Span,
@@ -694,12 +705,8 @@ impl<'a, 'tcx, 'v> Visitor<'v> for CheckTypeWellFormedVisitor<'a, 'tcx> {
 
     fn visit_impl_item(&mut self, impl_item: &'v hir::ImplItem) {
         debug!("visit_impl_item: {:?}", impl_item);
-        let method_sig = match impl_item.node {
-            hir::ImplItemKind::Method(ref sig, _) => Some(sig),
-            _ => None
-        };
-        CheckTypeWellFormed::new(self.tcx)
-            .check_associated_item(impl_item.id, impl_item.span, method_sig);
+        let def_id = self.tcx.hir.local_def_id(impl_item.id);
+        ty::maps::queries::check_impl_item_well_formed::ensure(self.tcx, def_id);
         intravisit::walk_impl_item(self, impl_item)
     }
 }