From b441b801fa72dac0886b98dc68b02993dc07649e Mon Sep 17 00:00:00 2001
From: Iris Shi <0.0@owo.li>
Date: Sun, 21 Sep 2025 11:43:36 +0800
Subject: [PATCH] fix a crash in rustdoc merge finalize without input file

---
 src/librustdoc/lib.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 9871066b9eb5..904972f52d01 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -835,8 +835,10 @@ fn main_args(early_dcx: &mut EarlyDiagCtxt, at_args: &[String]) {
         config::InputMode::NoInputMergeFinalize => {
             return wrap_return(
                 dcx,
-                run_merge_finalize(render_options)
-                    .map_err(|e| format!("could not write merged cross-crate info: {e}")),
+                rustc_span::create_session_globals_then(options.edition, &[], None, || {
+                    run_merge_finalize(render_options)
+                        .map_err(|e| format!("could not write merged cross-crate info: {e}"))
+                }),
             );
         }
     };