review comments

src/librustc/hir/map/mod.rs

@@ -862,12 +862,12 @@ pub fn get_enclosing_scope(&self, hir_id: HirId) -> Option<HirId> {
     }
 
     /// Returns the defining scope for an opaque type definition.
-    pub fn get_defining_scope(&self, id: HirId) -> Option<HirId> {
+    pub fn get_defining_scope(&self, id: HirId) -> HirId {
         let mut scope = id;
         loop {
             scope = self.get_enclosing_scope(scope).unwrap_or(CRATE_HIR_ID);
             if scope == CRATE_HIR_ID {
-                return Some(CRATE_HIR_ID);
+                return CRATE_HIR_ID;
             }
             match self.get(scope) {
                 Node::Item(i) => {
@@ -880,7 +880,7 @@ pub fn get_defining_scope(&self, id: HirId) -> Option<HirId> {
                 _ => break,
             }
         }
-        Some(scope)
+        scope
     }
 
     pub fn get_parent_did(&self, id: HirId) -> DefId {

src/librustc/infer/opaque_types/mod.rs

@@ -1215,7 +1215,7 @@ pub fn may_define_opaque_type(
     let mut hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
 
     // Named opaque types can be defined by any siblings or children of siblings.
-    let scope = tcx.hir().get_defining_scope(opaque_hir_id).expect("could not get defining scope");
+    let scope = tcx.hir().get_defining_scope(opaque_hir_id);
     // We walk up the node tree until we hit the root or the scope of the opaque type.
     while hir_id != scope && hir_id != hir::CRATE_HIR_ID {
         hir_id = tcx.hir().get_parent_item(hir_id);

src/librustc_typeck/collect.rs

@@ -1717,9 +1717,7 @@ fn visit_trait_item(&mut self, it: &'tcx TraitItem) {
     }
 
     let hir_id = tcx.hir().as_local_hir_id(def_id).unwrap();
-    let scope = tcx.hir()
-        .get_defining_scope(hir_id)
-        .expect("could not get defining scope");
+    let scope = tcx.hir().get_defining_scope(hir_id);
     let mut locator = ConstraintLocator {
         def_id,
         tcx,