Strange log shown when error is rustfmt diff

[RalfJung]

This error

Diff in /checkout/compiler/rustc_const_eval/src/interpret/eval_context.rs at line 929:
     }

     #[must_use]
-    pub fn generate_stacktrace_from_stack(stack: &[Frame<'mir, 'tcx, M::Provenance, M::FrameExtra>]) -> Vec<FrameInfo<'tcx>> {
+    pub fn generate_stacktrace_from_stack(
+        stack: &[Frame<'mir, 'tcx, M::Provenance, M::FrameExtra>],
+    ) -> Vec<FrameInfo<'tcx>> {
         let mut frames = Vec::new();
         // This deliberately does *not* honor `requires_caller_location` since it is used for much
         // more than just panics.

is quoted in a strange (and wrong) way by the bot

Diff in /checkout/compiler/rustc_const_eval/src/interpret/eval_context.rs at line 929:
     }

     #[must_use]
-    pub fn generate_stacktrace_from_stack(stack: &[Frame<'mir, 'tcx, M::Provenance, M::FrameExtra>]) -> Vec<FrameInfo<'tcx>> {
+    pub fn generate_stacktrace_from_stack(
+        stack: &[Frame<'mir, 'tcx, M::Provenance, M::FrameExtra>],
         let mut frames = Vec::new();
         let mut frames = Vec::new();
         // This deliberately does *not* honor `requires_caller_location` since it is used for much
         // more than just panics.