From b1fb29b43209e90a108b493a9e0242e197a1b263 Mon Sep 17 00:00:00 2001
From: Matthew Hughes <matthewhughes934@gmail.com>
Date: Tue, 6 Oct 2026 19:58:53 +0100
Subject: [PATCH] Add regression test for issue 6300

It looks like this issue has been fixed, so add a test to ensure we
never regress.

You may ask _when_ this was fixed, the best I could do was bisect to
a merge commit: d97c4fb3e2fa63e0a4cb4ba442bc8786a5ad4f24, via:

    # use --first-parent so we don't try and build commits that were
    # originally added in rust-lang/rust, since it's a pain to find the
    # correct toolchain to build those against
    $ git bisect start --term-new=fixed --term-old=broken --first-parent main 46cb7d322055625c07823dea8fdfad4c07f98754
    $ git bisect run ./bisect.sh

Where `bisect.sh` is:

    #!/usr/bin/env bash

    set -o errexit

    if ! cargo build --quiet --bin rustfmt
    then
      echo "failed to build" >&2
      # exit: magic code that tells git-bisect to skip this commit (see
      # git-bisect(1))
      exit 125
    fi

    export LD_LIBRARY_PATH="$(rustc --print sysroot)/lib${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}"
    # reverse the exit code: the basis of 'git bisect' is that the 'new' commit is
    # bad, the 'old' commit is good (e.g. there's a bug in HEAD but not HEAD~4,
    # which commit introduced that?). But we want the _opposite_
    ! ./target/debug/rustfmt --check ./samples/bugs.rs >/dev/null

References: rust-lang/rustfmt#6300
---
 tests/target/issue_6300.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 tests/target/issue_6300.rs

diff --git a/tests/target/issue_6300.rs b/tests/target/issue_6300.rs
new file mode 100644
index 00000000000..bb5a3673243
--- /dev/null
+++ b/tests/target/issue_6300.rs
@@ -0,0 +1,11 @@
+const B: b = b {
+    c: d,
+    /* block comment, has bug */
+    ..
+};
+
+const C: c = c {
+    c: d,
+    // line comment has bug
+    ..
+};