Rollup merge of #60750 - petrochenkov:noquotok2, r=Mark-Simulacrum

syntax: Remove some legacy nonterminal tokens

They were used by legacy quote macros removed in https://github.com/rust-lang/rust/pull/51285.

src/libsyntax/mut_visit.rs

@@ -663,7 +663,6 @@ pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis:
         token::NtMeta(meta) => vis.visit_meta_item(meta),
         token::NtPath(path) => vis.visit_path(path),
         token::NtTT(tt) => vis.visit_tt(tt),
-        token::NtArm(arm) => vis.visit_arm(arm),
         token::NtImplItem(item) =>
             visit_clobber(item, |item| {
                 // See reasoning above.
@@ -676,9 +675,6 @@ pub fn noop_visit_interpolated<T: MutVisitor>(nt: &mut token::Nonterminal, vis:
                 vis.flat_map_trait_item(item)
                     .expect_one("expected visitor to produce exactly one item")
             }),
-        token::NtGenerics(generics) => vis.visit_generics(generics),
-        token::NtWhereClause(where_clause) => vis.visit_where_clause(where_clause),
-        token::NtArg(arg) => vis.visit_arg(arg),
         token::NtVis(visib) => vis.visit_vis(visib),
         token::NtForeignItem(item) =>
             visit_clobber(item, |item| {

src/libsyntax/parse/parser.rs

@@ -1925,8 +1925,6 @@ impl<'a> Parser<'a> {
     /// This version of parse arg doesn't necessarily require identifier names.
     fn parse_arg_general(&mut self, require_name: bool, is_trait_item: bool,
                          allow_c_variadic: bool) -> PResult<'a, Arg> {
-        maybe_whole!(self, NtArg, |x| x);
-
         if let Ok(Some(_)) = self.parse_self_arg() {
             let mut err = self.struct_span_err(self.prev_span,
                 "unexpected `self` argument in function");
@@ -4179,8 +4177,6 @@ impl<'a> Parser<'a> {
     }
 
     crate fn parse_arm(&mut self) -> PResult<'a, Arm> {
-        maybe_whole!(self, NtArm, |x| x);
-
         let attrs = self.parse_outer_attributes()?;
         let pats = self.parse_pats()?;
         let guard = if self.eat_keyword(keywords::If) {
@@ -5915,8 +5911,6 @@ impl<'a> Parser<'a> {
     ///                  | ( < lifetimes , typaramseq ( , )? > )
     /// where   typaramseq = ( typaram ) | ( typaram , typaramseq )
     fn parse_generics(&mut self) -> PResult<'a, ast::Generics> {
-        maybe_whole!(self, NtGenerics, |x| x);
-
         let span_lo = self.span;
         if self.eat_lt() {
             let params = self.parse_generic_params()?;
@@ -6169,8 +6163,6 @@ impl<'a> Parser<'a> {
     /// where T : Trait<U, V> + 'b, 'a : 'b
     /// ```
     fn parse_where_clause(&mut self) -> PResult<'a, WhereClause> {
-        maybe_whole!(self, NtWhereClause, |x| x);
-
         let mut where_clause = WhereClause {
             id: ast::DUMMY_NODE_ID,
             predicates: Vec::new(),

src/libsyntax/parse/token.rs

@@ -585,14 +585,12 @@ pub enum Nonterminal {
     NtPath(ast::Path),
     NtVis(ast::Visibility),
     NtTT(TokenTree),
-    // These are not exposed to macros, but are used by quasiquote.
-    NtArm(ast::Arm),
-    NtImplItem(ast::ImplItem),
+    // Used only for passing items to proc macro attributes (they are not
+    // strictly necessary for that, `Annotatable` can be converted into
+    // tokens directly, but doing that naively regresses pretty-printing).
     NtTraitItem(ast::TraitItem),
+    NtImplItem(ast::ImplItem),
     NtForeignItem(ast::ForeignItem),
-    NtGenerics(ast::Generics),
-    NtWhereClause(ast::WhereClause),
-    NtArg(ast::Arg),
 }
 
 impl PartialEq for Nonterminal {
@@ -625,13 +623,9 @@ impl fmt::Debug for Nonterminal {
             NtMeta(..) => f.pad("NtMeta(..)"),
             NtPath(..) => f.pad("NtPath(..)"),
             NtTT(..) => f.pad("NtTT(..)"),
-            NtArm(..) => f.pad("NtArm(..)"),
             NtImplItem(..) => f.pad("NtImplItem(..)"),
             NtTraitItem(..) => f.pad("NtTraitItem(..)"),
             NtForeignItem(..) => f.pad("NtForeignItem(..)"),
-            NtGenerics(..) => f.pad("NtGenerics(..)"),
-            NtWhereClause(..) => f.pad("NtWhereClause(..)"),
-            NtArg(..) => f.pad("NtArg(..)"),
             NtVis(..) => f.pad("NtVis(..)"),
             NtLifetime(..) => f.pad("NtLifetime(..)"),
         }

src/libsyntax/print/pprust.rs

@@ -278,12 +278,8 @@ pub fn nonterminal_to_string(nt: &Nonterminal) -> String {
         token::NtLifetime(e)        => ident_to_string(e),
         token::NtLiteral(ref e)     => expr_to_string(e),
         token::NtTT(ref tree)       => tt_to_string(tree.clone()),
-        token::NtArm(ref e)         => arm_to_string(e),
         token::NtImplItem(ref e)    => impl_item_to_string(e),
         token::NtTraitItem(ref e)   => trait_item_to_string(e),
-        token::NtGenerics(ref e)    => generic_params_to_string(&e.params),
-        token::NtWhereClause(ref e) => where_clause_to_string(e),
-        token::NtArg(ref e)         => arg_to_string(e),
         token::NtVis(ref e)         => vis_to_string(e),
         token::NtForeignItem(ref e) => foreign_item_to_string(e),
     }