Merging upstream version 1.72.1+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

4 files changed, 45 insertions, 20 deletions

diff --git a/compiler/rustc_expand/src/mbe/diagnostics.rs b/compiler/rustc_expand/src/mbe/diagnostics.rs
index cb8b4899e..3593bed2d 100644
--- a/compiler/rustc_expand/src/mbe/diagnostics.rs
+++ b/compiler/rustc_expand/src/mbe/diagnostics.rs
@@ -170,7 +170,7 @@ impl<'a, 'cx, 'matcher> Tracker<'matcher> for CollectTrackerAndEmitter<'a, 'cx,
             }
             Error(err_sp, msg) => {
                 let span = err_sp.substitute_dummy(self.root_span);
-                self.cx.struct_span_err(span, msg.as_str()).emit();
+                self.cx.struct_span_err(span, msg.clone()).emit();
                 self.result = Some(DummyResult::any(span));
             }
             ErrorReported(_) => self.result = Some(DummyResult::any(self.root_span)),
@@ -222,7 +222,7 @@ pub(super) fn emit_frag_parse_err(
     {
         let msg = &e.message[0];
         e.message[0] = (
-            DiagnosticMessage::Str(format!(
+            DiagnosticMessage::from(format!(
                 "macro expansion ends with an incomplete expression: {}",
                 message.replace(", found `<eof>`", ""),
             )),
@@ -313,9 +313,9 @@ pub(super) fn annotate_doc_comment(err: &mut Diagnostic, sm: &SourceMap, span: S
 
 /// Generates an appropriate parsing failure message. For EOF, this is "unexpected end...". For
 /// other tokens, this is "unexpected token...".
-pub(super) fn parse_failure_msg(tok: &Token) -> String {
+pub(super) fn parse_failure_msg(tok: &Token) -> Cow<'static, str> {
     match tok.kind {
-        token::Eof => "unexpected end of macro invocation".to_string(),
-        _ => format!("no rules expected the token `{}`", pprust::token_to_string(tok),),
+        token::Eof => Cow::from("unexpected end of macro invocation"),
+        _ => Cow::from(format!("no rules expected the token `{}`", pprust::token_to_string(tok))),
     }
 }
diff --git a/compiler/rustc_expand/src/mbe/macro_parser.rs b/compiler/rustc_expand/src/mbe/macro_parser.rs
index 1c222fb4a..f0e67cfd5 100644
--- a/compiler/rustc_expand/src/mbe/macro_parser.rs
+++ b/compiler/rustc_expand/src/mbe/macro_parser.rs
@@ -249,6 +249,7 @@ pub(super) fn compute_locs(matcher: &[TokenTree]) -> Vec<MatcherLoc> {
 }
 
 /// A single matcher position, representing the state of matching.
+#[derive(Debug)]
 struct MatcherPos {
     /// The index into `TtParser::locs`, which represents the "dot".
     idx: usize,
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index e4c65a204..42cc0a6b1 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -223,8 +223,7 @@ fn expand_macro<'cx>(
             // Replace all the tokens for the corresponding positions in the macro, to maintain
             // proper positions in error reporting, while maintaining the macro_backtrace.
             if tts.len() == rhs.tts.len() {
-                tts = tts.map_enumerated(|i, tt| {
-                    let mut tt = tt.clone();
+                tts = tts.map_enumerated_owned(|i, mut tt| {
                     let rhs_tt = &rhs.tts[i];
                     let ctxt = tt.span().ctxt();
                     match (&mut tt, rhs_tt) {
@@ -535,7 +534,7 @@ pub fn compile_declarative_macro(
                     .pop()
                     .unwrap();
                 }
-                sess.parse_sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs")
+                sess.parse_sess.span_diagnostic.span_bug(def.span, "wrong-structured rhs")
             })
             .collect::<Vec<mbe::TokenTree>>(),
         _ => sess.parse_sess.span_diagnostic.span_bug(def.span, "wrong-structured rhs"),
@@ -628,6 +627,40 @@ fn check_lhs_nt_follows(sess: &ParseSess, def: &ast::Item, lhs: &mbe::TokenTree)
     // after parsing/expansion. we can report every error in every macro this way.
 }
 
+fn is_empty_token_tree(sess: &ParseSess, seq: &mbe::SequenceRepetition) -> bool {
+    if seq.separator.is_some() {
+        false
+    } else {
+        let mut is_empty = true;
+        let mut iter = seq.tts.iter().peekable();
+        while let Some(tt) = iter.next() {
+            match tt {
+                mbe::TokenTree::MetaVarDecl(_, _, Some(NonterminalKind::Vis)) => {}
+                mbe::TokenTree::Token(t @ Token { kind: DocComment(..), .. }) => {
+                    let mut now = t;
+                    while let Some(&mbe::TokenTree::Token(
+                        next @ Token { kind: DocComment(..), .. },
+                    )) = iter.peek()
+                    {
+                        now = next;
+                        iter.next();
+                    }
+                    let span = t.span.to(now.span);
+                    sess.span_diagnostic.span_note_without_error(
+                        span,
+                        "doc comments are ignored in matcher position",
+                    );
+                }
+                mbe::TokenTree::Sequence(_, sub_seq)
+                    if (sub_seq.kleene.op == mbe::KleeneOp::ZeroOrMore
+                        || sub_seq.kleene.op == mbe::KleeneOp::ZeroOrOne) => {}
+                _ => is_empty = false,
+            }
+        }
+        is_empty
+    }
+}
+
 /// Checks that the lhs contains no repetition which could match an empty token
 /// tree, because then the matcher would hang indefinitely.
 fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[mbe::TokenTree]) -> bool {
@@ -644,16 +677,7 @@ fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[mbe::TokenTree]) -> bool {
                 }
             }
             TokenTree::Sequence(span, seq) => {
-                if seq.separator.is_none()
-                    && seq.tts.iter().all(|seq_tt| match seq_tt {
-                        TokenTree::MetaVarDecl(_, _, Some(NonterminalKind::Vis)) => true,
-                        TokenTree::Sequence(_, sub_seq) => {
-                            sub_seq.kleene.op == mbe::KleeneOp::ZeroOrMore
-                                || sub_seq.kleene.op == mbe::KleeneOp::ZeroOrOne
-                        }
-                        _ => false,
-                    })
-                {
+                if is_empty_token_tree(sess, seq) {
                     let sp = span.entire();
                     sess.span_diagnostic.span_err(sp, "repetition matches empty token tree");
                     return false;
diff --git a/compiler/rustc_expand/src/mbe/quoted.rs b/compiler/rustc_expand/src/mbe/quoted.rs
index b2bdf9c7e..40bfa3715 100644
--- a/compiler/rustc_expand/src/mbe/quoted.rs
+++ b/compiler/rustc_expand/src/mbe/quoted.rs
@@ -9,7 +9,7 @@ use rustc_session::parse::{feature_err, ParseSess};
 use rustc_span::symbol::{kw, sym, Ident};
 
 use rustc_span::edition::Edition;
-use rustc_span::{Span, SyntaxContext};
+use rustc_span::Span;
 
 const VALID_FRAGMENT_NAMES_MSG: &str = "valid fragment specifiers are \
                                         `ident`, `block`, `stmt`, `expr`, `pat`, `ty`, `lifetime`, \
@@ -72,7 +72,7 @@ pub(super) fn parse(
                                             // `SyntaxContext::root()` from a foreign crate will
                                             // have the edition of that crate (which we manually
                                             // retrieve via the `edition` parameter).
-                                            if span.ctxt() == SyntaxContext::root() {
+                                            if span.ctxt().is_root() {
                                                 edition
                                             } else {
                                                 span.edition()