From 486585242e57ba184f26547c52c428dbf135e762 Mon Sep 17 00:00:00 2001
From: inquisitivecrystal
 <22333129+inquisitivecrystal@users.noreply.github.com>
Date: Sun, 2 Jan 2022 21:11:16 -0800
Subject: [PATCH] Do not resolve blocks in foreign functions

---
 compiler/rustc_resolve/src/late.rs | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index 5098cef11e8..b3ee042fd0a 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -520,9 +520,16 @@ impl<'a: 'ast, 'ast> Visitor<'ast> for LateResolutionVisitor<'a, '_, 'ast> {
     }
     fn visit_fn(&mut self, fn_kind: FnKind<'ast>, sp: Span, _: NodeId) {
         let rib_kind = match fn_kind {
-            // Bail if there's no body.
-            FnKind::Fn(.., None) => return visit::walk_fn(self, fn_kind, sp),
-            FnKind::Fn(FnCtxt::Free | FnCtxt::Foreign, ..) => FnItemRibKind,
+            // Bail if the function is foreign, and thus cannot validly have
+            // a body, or if there's no body for some other reason.
+            FnKind::Fn(FnCtxt::Foreign, _, sig, ..) | FnKind::Fn(_, _, sig, .., None) => {
+                // We don't need to deal with patterns in parameters, because
+                // they are not possible for foreign or bodiless functions.
+                self.visit_fn_header(&sig.header);
+                visit::walk_fn_decl(self, &sig.decl);
+                return;
+            }
+            FnKind::Fn(FnCtxt::Free, ..) => FnItemRibKind,
             FnKind::Fn(FnCtxt::Assoc(_), ..) => NormalRibKind,
             FnKind::Closure(..) => ClosureOrAsyncRibKind,
         };