diff --git a/src/librustc_ast_lowering/item.rs b/src/librustc_ast_lowering/item.rs
index eced17c9245f2..8093dc2827011 100644
--- a/src/librustc_ast_lowering/item.rs
+++ b/src/librustc_ast_lowering/item.rs
@@ -13,7 +13,7 @@ use rustc_hir::def::{DefKind, Res};
 use rustc_hir::def_id::LocalDefId;
 use rustc_span::source_map::{respan, DesugaringKind};
 use rustc_span::symbol::{kw, sym, Ident};
-use rustc_span::Span;
+use rustc_span::{Span, DUMMY_SP};
 use rustc_target::spec::abi;
 
 use log::debug;
@@ -482,7 +482,13 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 let mut resolutions = self.expect_full_res_from_use(id);
                 // We want to return *something* from this function, so hold onto the first item
                 // for later.
-                let ret_res = self.lower_res(resolutions.next().unwrap_or(Res::Err));
+                let ret_res = self.lower_res(resolutions.next().unwrap_or_else(|| {
+                    self.sess.delay_span_bug(
+                        DUMMY_SP,
+                        &format!("missing `ret_res` for use_tree: {:?}", tree),
+                    );
+                    Res::Err
+                }));
 
                 // Here, we are looping over namespaces, if they exist for the definition
                 // being imported. We only handle type and value namespaces because we
diff --git a/src/librustc_passes/intrinsicck.rs b/src/librustc_passes/intrinsicck.rs
index b407276cfbecd..7546e1dabd89c 100644
--- a/src/librustc_passes/intrinsicck.rs
+++ b/src/librustc_passes/intrinsicck.rs
@@ -146,20 +146,19 @@ impl Visitor<'tcx> for ExprVisitor<'tcx> {
     }
 
     fn visit_expr(&mut self, expr: &'tcx hir::Expr<'tcx>) {
-        let res = if let hir::ExprKind::Path(ref qpath) = expr.kind {
-            self.tables.qpath_res(qpath, expr.hir_id)
-        } else {
-            Res::Err
-        };
-        if let Res::Def(DefKind::Fn, did) = res {
-            if self.def_id_is_transmute(did) {
-                let typ = self.tables.node_type(expr.hir_id);
-                let sig = typ.fn_sig(self.tcx);
-                let from = sig.inputs().skip_binder()[0];
-                let to = *sig.output().skip_binder();
-                self.check_transmute(expr.span, from, to);
+        if let hir::ExprKind::Path(ref qpath) = expr.kind {
+            let res = self.tables.qpath_res(qpath, expr.hir_id);
+
+            if let Res::Def(DefKind::Fn, did) = res {
+                if self.def_id_is_transmute(did) {
+                    let typ = self.tables.node_type(expr.hir_id);
+                    let sig = typ.fn_sig(self.tcx);
+                    let from = sig.inputs().skip_binder()[0];
+                    let to = *sig.output().skip_binder();
+                    self.check_transmute(expr.span, from, to);
+                }
             }
-        }
+        };
 
         intravisit::walk_expr(self, expr);
     }