From 8240f1a3d3f0ff3e36c19836ea4d783f29752b0b Mon Sep 17 00:00:00 2001
From: Yuki Okushi <huyuumi.dev@gmail.com>
Date: Fri, 5 Mar 2021 14:52:45 +0900
Subject: Fix bad diagnostics for anon params with qualified paths

---
 compiler/rustc_parse/src/parser/diagnostics.rs | 30 +++++++++++++++++---------
 1 file changed, 20 insertions(+), 10 deletions(-)

(limited to 'compiler/rustc_parse')

diff --git a/compiler/rustc_parse/src/parser/diagnostics.rs b/compiler/rustc_parse/src/parser/diagnostics.rs
index f214b11d5f0..975b9cc15bd 100644
--- a/compiler/rustc_parse/src/parser/diagnostics.rs
+++ b/compiler/rustc_parse/src/parser/diagnostics.rs
@@ -1627,18 +1627,28 @@ impl<'a> Parser<'a> {
                 ),
                 // Also catches `fn foo(&a)`.
                 PatKind::Ref(ref pat, mutab) => {
-                    if let PatKind::Ident(_, ident, _) = pat.clone().into_inner().kind {
-                        let mutab = mutab.prefix_str();
-                        (
-                            ident,
-                            format!("self: &{}{}", mutab, ident),
-                            format!("{}: &{}TypeName", ident, mutab),
-                            format!("_: &{}{}", mutab, ident),
-                        )
-                    } else {
-                        return None;
+                    match pat.clone().into_inner().kind {
+                        PatKind::Ident(_, ident, _) => {
+                            let mutab = mutab.prefix_str();
+                            (
+                                ident,
+                                format!("self: &{}{}", mutab, ident),
+                                format!("{}: &{}TypeName", ident, mutab),
+                                format!("_: &{}{}", mutab, ident),
+                            )
+                        }
+                        PatKind::Path(..) => {
+                            err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)");
+                            return None;
+                        }
+                        _ => return None,
                     }
                 }
+                // Also catches `fn foo(<Bar as T>::Baz)`
+                PatKind::Path(..) => {
+                    err.note("anonymous parameters are removed in the 2018 edition (see RFC 1685)");
+                    return None;
+                }
                 // Ignore other `PatKind`.
                 _ => return None,
             };
-- 
cgit 1.4.1-3-g733a5