Auto merge of #124141 - nnethercote:rm-Nonterminal-and-TokenKind-Interpolated, r=petrochenkov

Remove `Nonterminal` and `TokenKind::Interpolated`

A third attempt at this; the first attempt was #96724 and the second was #114647.

r? `@ghost`

7 files changed, 20 insertions, 46 deletions

diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index bcc2703c39b..c70e259b2cd 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -238,18 +238,6 @@ impl<'a> StripUnconfigured<'a> {
                     Some(AttrTokenTree::Delimited(sp, spacing, delim, inner))
                 }
                 AttrTokenTree::Token(
-                    Token {
-                        kind:
-                            TokenKind::NtIdent(..)
-                            | TokenKind::NtLifetime(..)
-                            | TokenKind::Interpolated(..),
-                        ..
-                    },
-                    _,
-                ) => {
-                    panic!("Nonterminal should have been flattened: {:?}", tree);
-                }
-                AttrTokenTree::Token(
                     Token { kind: TokenKind::OpenDelim(_) | TokenKind::CloseDelim(_), .. },
                     _,
                 ) => {
diff --git a/compiler/rustc_expand/src/mbe/diagnostics.rs b/compiler/rustc_expand/src/mbe/diagnostics.rs
index e60a9e83184..b663e959744 100644
--- a/compiler/rustc_expand/src/mbe/diagnostics.rs
+++ b/compiler/rustc_expand/src/mbe/diagnostics.rs
@@ -66,9 +66,7 @@ pub(super) fn failed_to_match_macro(
     }
 
     if let MatcherLoc::Token { token: expected_token } = &remaining_matcher
-        && (matches!(expected_token.kind, TokenKind::Interpolated(_))
-            || matches!(token.kind, TokenKind::Interpolated(_))
-            || matches!(expected_token.kind, TokenKind::OpenDelim(Delimiter::Invisible(_)))
+        && (matches!(expected_token.kind, TokenKind::OpenDelim(Delimiter::Invisible(_)))
             || matches!(token.kind, TokenKind::OpenDelim(Delimiter::Invisible(_))))
     {
         err.note("captured metavariables except for `:tt`, `:ident` and `:lifetime` cannot be compared to other tokens");
@@ -162,7 +160,7 @@ impl<'dcx, 'matcher> Tracker<'matcher> for CollectTrackerAndEmitter<'dcx, 'match
                     .is_none_or(|failure| failure.is_better_position(*approx_position))
                 {
                     self.best_failure = Some(BestFailure {
-                        token: token.clone(),
+                        token: *token,
                         position_in_tokenstream: *approx_position,
                         msg,
                         remaining_matcher: self
diff --git a/compiler/rustc_expand/src/mbe/macro_parser.rs b/compiler/rustc_expand/src/mbe/macro_parser.rs
index d709fd79281..0065f83eb4e 100644
--- a/compiler/rustc_expand/src/mbe/macro_parser.rs
+++ b/compiler/rustc_expand/src/mbe/macro_parser.rs
@@ -179,7 +179,7 @@ pub(super) fn compute_locs(matcher: &[TokenTree]) -> Vec<MatcherLoc> {
         for tt in tts {
             match tt {
                 TokenTree::Token(token) => {
-                    locs.push(MatcherLoc::Token { token: token.clone() });
+                    locs.push(MatcherLoc::Token { token: *token });
                 }
                 TokenTree::Delimited(span, _, delimited) => {
                     let open_token = Token::new(token::OpenDelim(delimited.delim), span.open);
@@ -648,7 +648,7 @@ impl TtParser {
                     // There are no possible next positions AND we aren't waiting for the black-box
                     // parser: syntax error.
                     return Failure(T::build_failure(
-                        parser.token.clone(),
+                        parser.token,
                         parser.approx_token_stream_pos(),
                         "no rules expected this token in macro call",
                     ));
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index 460a06f9c06..c138b090877 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -810,7 +810,7 @@ impl<'tt> FirstSets<'tt> {
                         // token could be the separator token itself.
 
                         if let (Some(sep), true) = (&seq_rep.separator, subfirst.maybe_empty) {
-                            first.add_one_maybe(TtHandle::from_token(sep.clone()));
+                            first.add_one_maybe(TtHandle::from_token(*sep));
                         }
 
                         // Reverse scan: Sequence comes before `first`.
@@ -873,7 +873,7 @@ impl<'tt> FirstSets<'tt> {
                     // If the sequence contents can be empty, then the first
                     // token could be the separator token itself.
                     if let (Some(sep), true) = (&seq_rep.separator, subfirst.maybe_empty) {
-                        first.add_one_maybe(TtHandle::from_token(sep.clone()));
+                        first.add_one_maybe(TtHandle::from_token(*sep));
                     }
 
                     assert!(first.maybe_empty);
@@ -949,7 +949,7 @@ impl<'tt> Clone for TtHandle<'tt> {
             // This variant *must* contain a `mbe::TokenTree::Token`, and not
             // any other variant of `mbe::TokenTree`.
             TtHandle::Token(mbe::TokenTree::Token(tok)) => {
-                TtHandle::Token(mbe::TokenTree::Token(tok.clone()))
+                TtHandle::Token(mbe::TokenTree::Token(*tok))
             }
 
             _ => unreachable!(),
@@ -1125,7 +1125,7 @@ fn check_matcher_core<'tt>(
                 let mut new;
                 let my_suffix = if let Some(sep) = &seq_rep.separator {
                     new = suffix_first.clone();
-                    new.add_one_maybe(TtHandle::from_token(sep.clone()));
+                    new.add_one_maybe(TtHandle::from_token(*sep));
                     &new
                 } else {
                     &suffix_first
diff --git a/compiler/rustc_expand/src/mbe/quoted.rs b/compiler/rustc_expand/src/mbe/quoted.rs
index 0ea53627fe7..3f037259956 100644
--- a/compiler/rustc_expand/src/mbe/quoted.rs
+++ b/compiler/rustc_expand/src/mbe/quoted.rs
@@ -283,7 +283,7 @@ fn parse_tree<'a>(
         }
 
         // `tree` is an arbitrary token. Keep it.
-        tokenstream::TokenTree::Token(token, _) => TokenTree::Token(token.clone()),
+        tokenstream::TokenTree::Token(token, _) => TokenTree::Token(*token),
 
         // `tree` is the beginning of a delimited set of tokens (e.g., `(` or `{`). We need to
         // descend into the delimited set and further parse it.
@@ -321,7 +321,7 @@ fn parse_kleene_op(
     match iter.next() {
         Some(tokenstream::TokenTree::Token(token, _)) => match kleene_op(token) {
             Some(op) => Ok(Ok((op, token.span))),
-            None => Ok(Err(token.clone())),
+            None => Ok(Err(*token)),
         },
         tree => Err(tree.map_or(span, tokenstream::TokenTree::span)),
     }
diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index 6e47ed6eb67..39186319b1c 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -1,5 +1,4 @@
 use std::mem;
-use std::sync::Arc;
 
 use rustc_ast::mut_visit::{self, MutVisitor};
 use rustc_ast::token::{
@@ -165,7 +164,7 @@ pub(super) fn transcribe<'a>(
                 if repeat_idx < repeat_len {
                     frame.idx = 0;
                     if let Some(sep) = sep {
-                        result.push(TokenTree::Token(sep.clone(), Spacing::Alone));
+                        result.push(TokenTree::Token(*sep, Spacing::Alone));
                     }
                     continue;
                 }
@@ -307,7 +306,9 @@ pub(super) fn transcribe<'a>(
                     let tt = match cur_matched {
                         MatchedSingle(ParseNtResult::Tt(tt)) => {
                             // `tt`s are emitted into the output stream directly as "raw tokens",
-                            // without wrapping them into groups.
+                            // without wrapping them into groups. Other variables are emitted into
+                            // the output stream as groups with `Delimiter::Invisible` to maintain
+                            // parsing priorities.
                             maybe_use_metavar_location(psess, &stack, sp, tt, &mut marker)
                         }
                         MatchedSingle(ParseNtResult::Ident(ident, is_raw)) => {
@@ -325,6 +326,11 @@ pub(super) fn transcribe<'a>(
                         MatchedSingle(ParseNtResult::Item(item)) => {
                             mk_delimited(item.span, MetaVarKind::Item, TokenStream::from_ast(item))
                         }
+                        MatchedSingle(ParseNtResult::Block(block)) => mk_delimited(
+                            block.span,
+                            MetaVarKind::Block,
+                            TokenStream::from_ast(block),
+                        ),
                         MatchedSingle(ParseNtResult::Stmt(stmt)) => {
                             let stream = if let StmtKind::Empty = stmt.kind {
                                 // FIXME: Properly collect tokens for empty statements.
@@ -385,15 +391,6 @@ pub(super) fn transcribe<'a>(
                         MatchedSingle(ParseNtResult::Vis(vis)) => {
                             mk_delimited(vis.span, MetaVarKind::Vis, TokenStream::from_ast(vis))
                         }
-                        MatchedSingle(ParseNtResult::Nt(nt)) => {
-                            // Other variables are emitted into the output stream as groups with
-                            // `Delimiter::Invisible` to maintain parsing priorities.
-                            // `Interpolated` is currently used for such groups in rustc parser.
-                            marker.visit_span(&mut sp);
-                            let use_span = nt.use_span();
-                            with_metavar_spans(|mspans| mspans.insert(use_span, sp));
-                            TokenTree::token_alone(token::Interpolated(Arc::clone(nt)), sp)
-                        }
                         MatchedSeq(..) => {
                             // We were unable to descend far enough. This is an error.
                             return Err(dcx.create_err(VarStillRepeating { span: sp, ident }));
@@ -441,7 +438,7 @@ pub(super) fn transcribe<'a>(
             // Nothing much to do here. Just push the token to the result, being careful to
             // preserve syntax context.
             mbe::TokenTree::Token(token) => {
-                let mut token = token.clone();
+                let mut token = *token;
                 mut_visit::visit_token(&mut marker, &mut token);
                 let tt = TokenTree::Token(token, Spacing::Alone);
                 result.push(tt);
diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs
index ee6306e3961..2706a5eb3d7 100644
--- a/compiler/rustc_expand/src/proc_macro_server.rs
+++ b/compiler/rustc_expand/src/proc_macro_server.rs
@@ -309,15 +309,6 @@ impl FromInternal<(TokenStream, &mut Rustc<'_, '_>)> for Vec<TokenTree<TokenStre
                     }));
                 }
 
-                Interpolated(nt) => {
-                    let stream = TokenStream::from_nonterminal_ast(&nt);
-                    trees.push(TokenTree::Group(Group {
-                        delimiter: pm::Delimiter::None,
-                        stream: Some(stream),
-                        span: DelimSpan::from_single(span),
-                    }))
-                }
-
                 OpenDelim(..) | CloseDelim(..) => unreachable!(),
                 Eof => unreachable!(),
             }