Rollup merge of rust-lang#69587 - petrochenkov:reqname, r=Centril

rustc_parse: Tweak the function parameter name check

The function doesn't need a full token, only its edition.

Noticed while implementing rust-lang#69384.
I'm still not sure whether normalized or unnormalized token is a better fit for the edition check here, so  rust-lang#69384 and this PR just keep the status quo behavior.
r? @Centril

src/librustc_parse/parser/item.rs

@@ -6,6 +6,7 @@ use crate::maybe_whole;
 
 use rustc_ast_pretty::pprust;
 use rustc_errors::{struct_span_err, Applicability, PResult, StashKey};
+use rustc_span::edition::Edition;
 use rustc_span::source_map::{self, Span};
 use rustc_span::symbol::{kw, sym, Symbol};
 use syntax::ast::{self, AttrStyle, AttrVec, Attribute, Ident, DUMMY_NODE_ID};
@@ -636,7 +637,7 @@ impl<'a> Parser<'a> {
     }
 
     pub fn parse_trait_item(&mut self) -> PResult<'a, Option<Option<P<AssocItem>>>> {
-        self.parse_assoc_item(|t| t.span.rust_2018())
+        self.parse_assoc_item(|edition| edition >= Edition::Edition2018)
     }
 
     /// Parses associated items.
@@ -1380,7 +1381,7 @@ impl<'a> Parser<'a> {
 /// The parsing configuration used to parse a parameter list (see `parse_fn_params`).
 ///
 /// The function decides if, per-parameter `p`, `p` must have a pattern or just a type.
-type ReqName = fn(&token::Token) -> bool;
+type ReqName = fn(Edition) -> bool;
 
 /// Parsing of functions and methods.
 impl<'a> Parser<'a> {
@@ -1536,7 +1537,7 @@ impl<'a> Parser<'a> {
 
         let is_name_required = match self.token.kind {
             token::DotDotDot => false,
-            _ => req_name(&self.normalized_token),
+            _ => req_name(self.normalized_token.span.edition()),
         };
         let (pat, ty) = if is_name_required || self.is_named_param() {
             debug!("parse_param_general parse_pat (is_name_required:{})", is_name_required);