avoid cycles in mir-dump, take 2

diff --git a/src/librustc_mir/util/pretty.rs b/src/librustc_mir/util/pretty.rs
index 14f277d1767bbc3faf3915ddec606226c46d6327..eaba573dcd2e582d21dfdc056e87ba601d820e94 100644 (file)
--- a/src/librustc_mir/util/pretty.rs
+++ b/src/librustc_mir/util/pretty.rs
@@ -324,7 +324,9 @@ fn write_mir_sig(tcx: TyCtxt, src: MirSource, mir: &Mir, w: &mut Write)
         MirSource::Promoted(_, i) => write!(w, "{:?} in", i)?
     }
 
-    write!(w, " {}", tcx.node_path_str(src.item_id()))?;
+    item_path::with_forced_impl_filename_line(|| { // see notes on #41697 elsewhere
+        write!(w, " {}", tcx.node_path_str(src.item_id()))
+    })?;
 
     if let MirSource::Fn(_) = src {
         write!(w, "(")?;