Rollup merge of rust-lang#69896 - petrochenkov:reqname2, r=Centril

parse: Tweak the function parameter edition check

Follow-up to rust-lang#69801.

Edition of a code fragment is inferred from "the place where the code is written".
For individual tokens like edition-specific keywords it may be the span of the token itself ("uninterpolated" span), but for larger code fragments it's probably not, in the test example the trait method is obviously written in "2015 edition code".

r? @Centril

src/librustc_parse/parser/item.rs

@@ -1544,9 +1544,7 @@ impl<'a> Parser<'a> {
 
         let is_name_required = match self.token.kind {
             token::DotDotDot => false,
-            // FIXME: Consider using interpolated token for this edition check,
-            // it should match the intent of edition hygiene better.
-            _ => req_name(self.token.uninterpolate().span.edition()),
+            _ => req_name(self.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);

src/test/ui/anon-params/anon-params-edition-hygiene.rs

@@ -0,0 +1,10 @@
+// check-pass
+// edition:2018
+// aux-build:anon-params-edition-hygiene.rs
+
+#[macro_use]
+extern crate anon_params_edition_hygiene;
+
+generate_trait_2015!(u8);
+
+fn main() {}

src/test/ui/anon-params/auxiliary/anon-params-edition-hygiene.rs

@@ -0,0 +1,12 @@
+// edition:2015
+
+#[macro_export]
+macro_rules! generate_trait_2015 {
+    ($Type: ident) => {
+        trait Trait {
+            fn method($Type) {}
+        }
+    };
+}
+
+fn main() {}