template-coq should handle primitive projections

[JasonGross]

Consider this unfortunate behavior:

(* -*- coq-prog-args: ("-emacs" "-debug") -*- *)
Require Import Template.Template.
Require Import Template.Ast.
Require Import Coq.Strings.String.
Open Scope string_scope.
Set Primitive Projections.
Set Implicit Arguments.

Record sigT {A} (P : A -> Type) := existT { projT1 : A ; projT2 : P projT1 }.

Quote Recursively Definition x := @projT1. (* Anomaly: Cannot detype an unfolded primitive projection.. Please report at http://coq.inria.fr/bugs/.
frame @ file "toplevel/vernac.ml", line 242, characters 30-75
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "toplevel/vernac.ml", line 203, characters 6-16
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 2828, characters 8-30
frame @ file "stm/stm.ml", line 2298, characters 2-35
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 2288, characters 4-48
frame @ file "stm/stm.ml", line 2255, characters 4-100
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 885, characters 6-10
frame @ file "stm/stm.ml", line 2140, characters 12-30
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 122, characters 15-71
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "lib/flags.ml", line 30, characters 14-17
raise @ unknown
frame @ file "toplevel/vernacentries.ml", line 2232, characters 10-389
frame @ file "lib/flags.ml", line 151, characters 20-45
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "lib/flags.ml", line 30, characters 14-17
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "toplevel/vernacinterp.ml", line 69, characters 4-10
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
frame @ file "format.ml", line 1200, characters 6-24
raise @ unknown
frame @ file "interp/constrextern.ml", line 965, characters 2-57
frame @ file "interp/constrextern.ml", line 957, characters 10-69
frame @ file "pretyping/detyping.ml", line 510, characters 7-69
raise @ file "lib/cErrors.ml", line 40, characters 18-39 *)
Definition foo A P (x : @sigT A P) := projT1 x.
Quote Recursively Definition x := foo. (* Anomaly: Uncaught exception Not_found. Please report at http://coq.inria.fr/bugs/.
frame @ file "toplevel/vernac.ml", line 242, characters 30-75
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "toplevel/vernac.ml", line 203, characters 6-16
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 2828, characters 8-30
frame @ file "stm/stm.ml", line 2298, characters 2-35
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 2288, characters 4-48
frame @ file "stm/stm.ml", line 2255, characters 4-100
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 885, characters 6-10
frame @ file "stm/stm.ml", line 2140, characters 12-30
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "stm/stm.ml", line 122, characters 15-71
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "lib/flags.ml", line 30, characters 14-17
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "toplevel/vernacentries.ml", line 2232, characters 10-389
frame @ file "lib/flags.ml", line 151, characters 20-45
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "lib/flags.ml", line 30, characters 14-17
raise @ file "lib/exninfo.ml", line 63, characters 8-15
frame @ file "toplevel/vernacinterp.ml", line 69, characters 4-10
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
raise @ unknown
frame @ file "format.ml", line 1200, characters 6-24
raise @ unknown
frame @ file "interp/constrextern.ml", line 965, characters 2-57
frame @ file "interp/constrextern.ml", line 957, characters 10-69
raise @ unknown
frame @ file "pretyping/detyping.ml", line 515, characters 15-64
frame @ file "pretyping/retyping.ml", line 247, characters 11-44
frame @ file "pretyping/retyping.ml", line 97, characters 19-37
raise @ file "kernel/context.ml", line 187, characters 28-37 *)