From 85b585daaf735deda96c6e087e2a3f203c64d52d Mon Sep 17 00:00:00 2001
From: Mazdak Farrokhzad <twingoow@gmail.com>
Date: Fri, 28 Feb 2020 07:58:37 +0100
Subject: [PATCH] late resolve, visit_fn: bail early if there's no body.

---
 src/librustc_resolve/late.rs                             | 5 +++--
 .../ui/resolve/issue-69401-trait-fn-no-body-ty-local.rs  | 6 ++++++
 .../resolve/issue-69401-trait-fn-no-body-ty-local.stderr | 9 +++++++++
 3 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.rs
 create mode 100644 src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.stderr

diff --git a/src/librustc_resolve/late.rs b/src/librustc_resolve/late.rs
index c924fef4dc9d2..48a2f829d1998 100644
--- a/src/librustc_resolve/late.rs
+++ b/src/librustc_resolve/late.rs
@@ -456,8 +456,9 @@ impl<'a, '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 {
-            FnKind::Fn(FnCtxt::Foreign, ..) => return visit::walk_fn(self, fn_kind, sp),
-            FnKind::Fn(FnCtxt::Free, ..) => FnItemRibKind,
+            // Bail if there's no body.
+            FnKind::Fn(.., None) => return visit::walk_fn(self, fn_kind, sp),
+            FnKind::Fn(FnCtxt::Free, ..) | FnKind::Fn(FnCtxt::Foreign, ..) => FnItemRibKind,
             FnKind::Fn(FnCtxt::Assoc(_), ..) | FnKind::Closure(..) => NormalRibKind,
         };
         let previous_value = replace(&mut self.diagnostic_metadata.current_function, Some(sp));
diff --git a/src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.rs b/src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.rs
new file mode 100644
index 0000000000000..4397baea4a940
--- /dev/null
+++ b/src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.rs
@@ -0,0 +1,6 @@
+fn main() {}
+
+trait Foo {
+    fn fn_with_type_named_same_as_local_in_param(b: b);
+    //~^ ERROR cannot find type `b` in this scope
+}
diff --git a/src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.stderr b/src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.stderr
new file mode 100644
index 0000000000000..109409d2731c5
--- /dev/null
+++ b/src/test/ui/resolve/issue-69401-trait-fn-no-body-ty-local.stderr
@@ -0,0 +1,9 @@
+error[E0412]: cannot find type `b` in this scope
+  --> $DIR/issue-69401-trait-fn-no-body-ty-local.rs:4:53
+   |
+LL |     fn fn_with_type_named_same_as_local_in_param(b: b);
+   |                                                     ^ not found in this scope
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0412`.