Auto merge of #53612 - mark-i-m:anon_param_disallowed_2018, r=petrochenkov

Remove anonymous trait params from 2018 and beyond

cc @Centril @nikomatsakis
cc #41686 rust-lang/rfcs#2522 #53272

This PR removes support for anonymous trait parameters syntactically in rust 2018 and onward.

TODO:
- [x] Add tests

1 files changed, 7 insertions, 1 deletions

diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs
index 725360b842d..1695d3a8f96 100644
--- a/src/libsyntax/parse/parser.rs
+++ b/src/libsyntax/parse/parser.rs
@@ -1376,7 +1376,13 @@ impl<'a> Parser<'a> {
                 // This is somewhat dubious; We don't want to allow
                 // argument names to be left off if there is a
                 // definition...
-                p.parse_arg_general(false)
+
+                // We don't allow argument names to be left off in edition 2018.
+                if p.span.edition() >= Edition::Edition2018 {
+                    p.parse_arg_general(true)
+                } else {
+                    p.parse_arg_general(false)
+                }
             })?;
             generics.where_clause = self.parse_where_clause()?;