Strange failure with rebel.

[jordwalke]

There's this output that BetterErrors fails to parse, and it's strange because the output that rebel adds makes it fail:

File "src/nav.re", line 86, characters 16-92:
Error: This pattern matches values of type
         (Rk.Layer.t, TapGesture.t) Lib.ReactCore.graphDelegate
           =
           (Lib.Id.t,
            Rk.Layer.t Lib.ReactCore.opaqueGraph, TapGesture.t,
            Rk.Layer.t Lib.ReactCore.opaqueGraph)
           Prelude__Core.delegate
       but a pattern was expected which matches values of type 'a option

- exit . Top__Nav.cmi, 47ms, exited with code 2
*** jenga: 233/242 targets are up to date
*** jenga: failed (#1, 240ms, heap=204.312m, stat=659, digest=1, ls=8, db-save=0)
*** jenga: todo: 0 (233 / 242) !1 ~8 j=0+0 con=242 save=0 act=9, finished
*** jenga: ERROR: (summary) _build/top/Top__Nav.cmi: External command failed
      - build . Top__Nav.cmi
      + bash -c 'ocamlfind ocamlc -package js_of_ocaml -pp refmt -bin-annot -g -w -30 -w -40 -open Top -I _build/top -I _build/Lib -I _build/CoreGraphics -I _build/QuartzCore -I _build/Rk -I _build/Prelude -o _build/top/Top__Nav -c -intf-suffix .rei -impl src/nav.re 2>&1; (exit ${PIPESTATUS[0]})'
      File "src/nav.re", line 86, characters 16-92:
      Error: This pattern matches values of type
               (Rk.Layer.t, TapGesture.t) Lib.ReactCore.graphDelegate
                 =
                 (Lib.Id.t,
                  Rk.Layer.t Lib.ReactCore.opaqueGraph, TapGesture.t,
                  Rk.Layer.t Lib.ReactCore.opaqueGraph)
                 Prelude__Core.delegate
             but a pattern was expected which matches values of type 'a option
      - exit . Top__Nav.cmi, 47ms, exited with code 2
*** jenga: build finished; not in polling mode so quitting
*** jenga: Quit; exit_code = 1
✔ Seems fine!

But then if you just un-indent the second error above, then the error message parses correctly in BetterErrors.