diff --git a/src/librustc/hir/lowering/item.rs b/src/librustc/hir/lowering/item.rs
index 7b774812a24f2..dd95d99d4e1d6 100644
--- a/src/librustc/hir/lowering/item.rs
+++ b/src/librustc/hir/lowering/item.rs
@@ -60,10 +60,12 @@ impl<'tcx, 'interner> Visitor<'tcx> for ItemLowerer<'tcx, 'interner> {
     fn visit_item(&mut self, item: &'tcx Item) {
         let mut item_hir_id = None;
         self.lctx.with_hir_id_owner(item.id, |lctx| {
-            if let Some(hir_item) = lctx.lower_item(item) {
-                item_hir_id = Some(hir_item.hir_id);
-                lctx.insert_item(hir_item);
-            }
+            lctx.without_in_scope_lifetime_defs(|lctx| {
+                if let Some(hir_item) = lctx.lower_item(item) {
+                    item_hir_id = Some(hir_item.hir_id);
+                    lctx.insert_item(hir_item);
+                }
+            })
         });
 
         if let Some(hir_id) = item_hir_id {
@@ -134,6 +136,28 @@ impl LoweringContext<'_> {
         res
     }
 
+    // Clears (and restores) the `in_scope_lifetimes` field. Used when
+    // visiting nested items, which never inherit in-scope lifetimes
+    // from their surrounding environment.
+    fn without_in_scope_lifetime_defs<T>(
+        &mut self,
+        f: impl FnOnce(&mut LoweringContext<'_>) -> T,
+    ) -> T {
+        let old_in_scope_lifetimes = std::mem::replace(&mut self.in_scope_lifetimes, vec![]);
+
+        // this vector is only used when walking over impl headers,
+        // input types, and the like, and should not be non-empty in
+        // between items
+        assert!(self.lifetimes_to_define.is_empty());
+
+        let res = f(self);
+
+        assert!(self.in_scope_lifetimes.is_empty());
+        self.in_scope_lifetimes = old_in_scope_lifetimes;
+
+        res
+    }
+
     pub(super) fn lower_mod(&mut self, m: &Mod) -> hir::Mod {
         hir::Mod {
             inner: m.inner,
diff --git a/src/test/ui/async-await/nested-in-impl.rs b/src/test/ui/async-await/nested-in-impl.rs
new file mode 100644
index 0000000000000..3c82160595f1d
--- /dev/null
+++ b/src/test/ui/async-await/nested-in-impl.rs
@@ -0,0 +1,17 @@
+// Test that async fn works when nested inside of
+// impls with lifetime parameters.
+//
+// check-pass
+// edition:2018
+
+#![feature(async_await)]
+
+struct Foo<'a>(&'a ());
+
+impl<'a> Foo<'a> {
+    fn test() {
+        async fn test() {}
+    }
+}
+
+fn main() { }
diff --git a/src/test/ui/in-band-lifetimes/nested-items.rs b/src/test/ui/in-band-lifetimes/nested-items.rs
new file mode 100644
index 0000000000000..7de20712fba94
--- /dev/null
+++ b/src/test/ui/in-band-lifetimes/nested-items.rs
@@ -0,0 +1,20 @@
+// Test that the `'a` from the impl doesn't
+// prevent us from creating a `'a` parameter
+// on the `blah` function.
+//
+// check-pass
+
+#![feature(in_band_lifetimes)]
+
+struct Foo<'a> {
+    x: &'a u32
+
+}
+
+impl Foo<'a> {
+    fn method(&self) {
+        fn blah(f: Foo<'a>) { }
+    }
+}
+
+fn main() { }