Auto merge of rust-lang#98020 - TaKO8Ki:use-create-snapshot-for-diagnostic-in-rustc-expand, r=Dylan-DPC

Use `create_snapshot_for_diagnostic` instead of `clone` for `Parser` Use [`create_snapshot_for_diagnostic`](https://github.com/rust-lang/rust/blob/cd119057160cedea245aa2679add56723f3dc784/compiler/rustc_parse/src/parser/diagnostics.rs#L214-L223) I implemented in rust-lang#94731 instead of `clone` to avoid duplicate unclosed delims errors being emitted when the `Parser` is dropped. I missed this one in rust-lang#95068.

Author: bors

compiler/rustc_expand/src/mbe/macro_rules.rs

@@ -123,7 +123,7 @@ impl<'a> ParserAnyMacro<'a> {
  is_trailing_mac,
  is_local,
  } = *self;
- let snapshot = &mut parser.clone();
+ let snapshot = &mut parser.create_snapshot_for_diagnostic();
  let fragment = match parse_ast_fragment(parser, kind) {
  Ok(f) => f,
  Err(err) => {

compiler/rustc_parse/src/parser/diagnostics.rs

@@ -336,7 +336,7 @@ struct InInTypo {
 // SnapshotParser is used to create a snapshot of the parser
 // without causing duplicate errors being emitted when the `Parser`
 // is dropped.
-pub(super) struct SnapshotParser<'a> {
+pub struct SnapshotParser<'a> {
  parser: Parser<'a>,
  unclosed_delims: Vec<UnmatchedBrace>,
 }
@@ -392,7 +392,7 @@ impl<'a> Parser<'a> {
  }
 
  /// Create a snapshot of the `Parser`.
- pub(super) fn create_snapshot_for_diagnostic(&self) -> SnapshotParser<'a> {
+ pub fn create_snapshot_for_diagnostic(&self) -> SnapshotParser<'a> {
  let mut snapshot = self.clone();
  let unclosed_delims = self.unclosed_delims.clone();
  // Clear `unclosed_delims` in snapshot to avoid