Fix #7904: update proofview env after ltac constr:()

(in case of side effects)

Also:
Fix #4781
Fix #4496

2 files changed, 22 insertions, 7 deletions

diff --git a/test-suite/bugs/opened/bug_4781.v b/test-suite/bugs/closed/bug_4781.v
index 8b651ac22e..464a3de1b3 100644
--- a/test-suite/bugs/opened/bug_4781.v
+++ b/test-suite/bugs/closed/bug_4781.v
@@ -25,29 +25,29 @@ Goal True.
   let x := match constr:(Set) with ?y => constr:(y) end in
   pose x.
 (* This fails with an error: *)
-  Fail let term := constr:(I) in
+  let term := constr:(I) in
   let T := type of term in
   let x := constr:((_ : abstract_term term) : T) in
   let x := match constr:(x) with ?y => constr:(y) end in
   pose x. (* The command has indeed failed with message:
 Error: Variable y should be bound to a term. *)
 (* And the rest fail with Anomaly: Uncaught exception Not_found. Please report. *)
-  Fail let term := constr:(I) in
+  let term := constr:(I) in
   let T := type of term in
   let x := constr:((_ : abstract_term term) : T) in
   let x := match constr:(x) with ?y => y end in
   pose x.
-  Fail let term := constr:(I) in
+  let term := constr:(I) in
   let T := type of term in
   let x := constr:((_ : abstract_term term) : T) in
   let x := (eval cbv iota in x) in
   pose x.
-  Fail let term := constr:(I) in
+  let term := constr:(I) in
   let T := type of term in
   let x := constr:((_ : abstract_term term) : T) in
   let x := type of x in
   pose x. (* should succeed *)
-  Fail let term := constr:(I) in
+  let term := constr:(I) in
   let T := type of term in
   let x := constr:(_ : abstract_term term) in
   let x := type of x in
@@ -70,7 +70,7 @@ Even stranger, consider:*)
 
 (*This works fine.  But if I change the period to a semicolon, I get:*)
 
-      Fail let term := constr:(I) in
+      let term := constr:(I) in
   let T := type of term in
   let x := constr:((_ : abstract_term term) : T) in
   let y := (eval cbv iota in (let v : T := x in v)) in
@@ -82,7 +82,7 @@ Even stranger, consider:*)
  (* should succeed *)
 (*and if I use the second one instead of [pose x] (note that using [idtac] works fine), I get:*)
 
- Fail  let term := constr:(I) in
+  let term := constr:(I) in
   let T := type of term in
   let x := constr:((_ : abstract_term term) : T) in
   let y := (eval cbv iota in (let v : T := x in v)) in
@@ -92,3 +92,5 @@ Even stranger, consider:*)
       let x := (eval cbv delta [x'] in x') in
       let z := (eval cbv iota in x) in (* Error: Variable x should be bound to a term. *)
       idtac. (* should succeed *)
+  exact I.
+Qed.
diff --git a/test-suite/bugs/closed/bug_7904.v b/test-suite/bugs/closed/bug_7904.v
new file mode 100644
index 0000000000..1e518e2adf
--- /dev/null
+++ b/test-suite/bugs/closed/bug_7904.v
@@ -0,0 +1,13 @@
+
+
+Class abstract_term {T} (x : T) := by_abstract_term : T.
+Hint Extern 0 (@abstract_term ?T ?x) => change T; abstract (exact x) : typeclass_instances.
+
+Goal True.
+  let term := constr:(I) in
+  let T := type of term in
+  let x := constr:((_ : abstract_term term) : T) in
+  let x := match constr:(x) with ?y => y end in
+  pose x as v. (* was Error: Variable x should be bound to a term but is bound to a constr. *)
+  exact v.
+Qed.