Move the static check of evaluability in unfold tactic to runtime.

See #11840 for a motivation. I had to fix Floats.FloatLemmas because
it uses the same name for a notation and a term, and the fact this
unfold was working on this was clearly a bug. I hope nobody relies
on this kind of stuff in the wild.

Fixes #5764: "Cannot coerce ..." should be a runtime error.
Fixes #5159: "Cannot coerce ..." should not be an error.
Fixes #4925: unfold gives error on Admitted.

4 files changed, 29 insertions, 4 deletions

diff --git a/test-suite/bugs/closed/bug_4925.v b/test-suite/bugs/closed/bug_4925.v
new file mode 100644
index 0000000000..d4e4b35351
--- /dev/null
+++ b/test-suite/bugs/closed/bug_4925.v
@@ -0,0 +1,6 @@
+Axiom a: bool.
+
+Goal a = true.
+Proof.
+try unfold a.
+Abort.
diff --git a/test-suite/bugs/closed/bug_5159.v b/test-suite/bugs/closed/bug_5159.v
new file mode 100644
index 0000000000..cbc924c2d3
--- /dev/null
+++ b/test-suite/bugs/closed/bug_5159.v
@@ -0,0 +1,12 @@
+Axiom foo : Type.
+Definition bar := 1.
+Definition bar' := Eval cbv -[bar] in bar.
+Declare Reduction red' := cbv -[bar].
+Opaque bar.
+Definition bar'' := Eval red' in bar.
+Declare Reduction red'' := cbv -[bar]. (* Error: Cannot coerce bar to an
+evaluable reference. *)
+Definition bar''' := Eval cbv -[bar] in bar. (* Error: Cannot coerce bar to an
+evaluable reference. *)
+Definition foo' := Eval cbv -[foo] in foo. (* Error: Cannot coerce foo to an
+evaluable reference. *)
diff --git a/test-suite/bugs/closed/bug_5764.v b/test-suite/bugs/closed/bug_5764.v
new file mode 100644
index 0000000000..0b015d9c7e
--- /dev/null
+++ b/test-suite/bugs/closed/bug_5764.v
@@ -0,0 +1,7 @@
+Module Type A.
+Parameter a : nat.
+End A.
+
+Module B (mA : A).
+Ltac cbv_a := cbv [mA.a].
+End B.
diff --git a/test-suite/success/with_strategy.v b/test-suite/success/with_strategy.v
index 077b57c87f..6f0833211e 100644
--- a/test-suite/success/with_strategy.v
+++ b/test-suite/success/with_strategy.v
@@ -195,8 +195,8 @@ Opaque F.id.
 
 Goal F.id 0 = F.id 0.
   Fail unfold F.id.
-  (* This should work, but it fails with "Cannot coerce F.id to an evaluable reference." *)
-  Fail F.with_transparent_id ltac:(progress unfold F.id).
+  F.with_transparent_id ltac:(progress unfold F.id).
+  Undo.
   F.with_transparent_id ltac:(let x := constr:(@F.id) in progress unfold x).
 Abort.
 
@@ -212,8 +212,8 @@ Opaque F2.id.
 
 Goal F2.id 0 = F2.id 0.
   Fail unfold F2.id.
-  (* This should work, but it fails with "Cannot coerce F2.id to an evaluable reference." *)
-  Fail F2.with_transparent_id ltac:(progress unfold F2.id).
+  F2.with_transparent_id ltac:(progress unfold F2.id).
+  Undo.
   F2.with_transparent_id ltac:(let x := constr:(@F2.id) in progress unfold x).
 Abort.