evarconv.ml: Fix bug #4529, primproj unfolding

Evarconv was made precociously dependent on user-declared reduction
behaviors. Only cbn should rely on that.

2 files changed, 46 insertions, 6 deletions

diff --git a/pretyping/evarconv.ml b/pretyping/evarconv.ml
index aead1cb35f..0d261f7f87 100644
--- a/pretyping/evarconv.ml
+++ b/pretyping/evarconv.ml
@@ -39,12 +39,7 @@ let _ = Goptions.declare_bool_option {
 let unfold_projection env evd ts p c =
   let cst = Projection.constant p in
     if is_transparent_constant ts cst then
-      let c' = Some (mkProj (Projection.make cst true, c)) in
-	match ReductionBehaviour.get (Globnames.ConstRef cst) with
-	| None -> c'
-	| Some (recargs, nargs, flags) ->
-	  if (List.mem `ReductionNeverUnfold flags) then None
-	  else c'
+      Some (mkProj (Projection.make cst true, c))
     else None
       
 let eval_flexible_term ts env evd c =
diff --git a/test-suite/bugs/closed/4529.v b/test-suite/bugs/closed/4529.v
new file mode 100644
index 0000000000..8b3c24fec6
--- /dev/null
+++ b/test-suite/bugs/closed/4529.v
@@ -0,0 +1,45 @@
+(* File reduced by coq-bug-finder from original input, then from 1334 lines to 1518 lines, then from 849 lines to 59 lines *)
+(* coqc version 8.5 (January 2016) compiled on Jan 22 2016 18:20:47 with OCaml 4.02.3
+   coqtop version r-schnelltop:/home/r/src/coq/coq,(HEAD detached at V8.5) (5e23fb90b39dfa014ae5c4fb46eb713cca09dbff) *)
+Require Coq.Setoids.Setoid.
+Import Coq.Setoids.Setoid.
+
+Class Equiv A := equiv: relation A.
+Infix "≡" := equiv (at level 70, no associativity).
+Notation "(≡)" := equiv (only parsing).
+
+(* If I remove this line, everything compiles. *)
+Set Primitive Projections.
+
+Class Dist A := dist : nat -> relation A.
+Notation "x ={ n }= y" := (dist n x y)
+  (at level 70, n at next level, format "x  ={ n }=  y").
+
+Record CofeMixin A `{Equiv A, Dist A} := {
+  mixin_equiv_dist x y : x ≡ y <-> forall n, x ={n}= y;
+  mixin_dist_equivalence n : Equivalence (dist n);
+}.
+
+Structure cofeT := CofeT {
+  cofe_car :> Type;
+  cofe_equiv : Equiv cofe_car;
+  cofe_dist : Dist cofe_car;
+  cofe_mixin : CofeMixin cofe_car
+}.
+Existing Instances cofe_equiv cofe_dist.
+Arguments cofe_car : simpl never.
+
+Section cofe_mixin.
+  Context {A : cofeT}.
+  Implicit Types x y : A.
+  Lemma equiv_dist x y : x ≡ y <-> forall n, x ={n}= y.
+Admitted.
+End cofe_mixin.
+  Context {A : cofeT}.
+  Global Instance cofe_equivalence : Equivalence ((≡) : relation A).
+  Proof.
+    split.
+    *
+ intros x.
+apply equiv_dist.
+