Two fixes in unification (bugs #3782 and #3709)

- In evarconv, check_conv_record properly computes the parameters of
primitive record projections for later unification, adding env and
sigma as arguments.
- In unification, backtrack on pattern-unification and not only
application unification if eta for a record failed.

1 files changed, 23 insertions, 0 deletions

diff --git a/test-suite/bugs/closed/3709.v b/test-suite/bugs/closed/3709.v
new file mode 100644
index 000000000..7f01be7ab
--- /dev/null
+++ b/test-suite/bugs/closed/3709.v
@@ -0,0 +1,23 @@
+Module NonPrim.
+  Unset Primitive Projections.
+  Record hProp := hp { hproptype :> Type }.
+  Goal forall (h : (Type -> hProp) -> (Type -> hProp)) k f,
+         (forall y, h y = y) ->
+         h (fun b : Type => {| hproptype := f b |}) = k.
+  Proof.
+    intros h k f H.
+    etransitivity.
+    apply H.
+    admit.
+  Defined.
+End NonPrim.
+Module Prim.
+  Set Primitive Projections.
+  Record hProp := hp { hproptype :> Type }.
+  Goal forall (h : (Type -> hProp) -> (Type -> hProp)) k f,
+         (forall y, h y = y) ->
+         h (fun b : Type => {| hproptype := f b |}) = k.
+  Proof.
+    intros h k f H.
+    etransitivity.
+    apply H.