case-analysis crashes with closed variant type #1601
Description
let foo : [< `Foo ] option = None
let () =
match foo with
| None | Some _ -> ()
;;Using the Merlin from 9fc6355, destructing on the _ gives:
File "src/analysis/destruct.ml", line 558, characters 20-26: Assertion failed
Raised at Merlin_analysis__Destruct.node in file "src/analysis/destruct.ml", line 558, characters 20-32
Called from Merlin_utils__Misc.try_finally in file "src/utils/misc.ml", line 45, characters 8-15
Re-raised at Merlin_utils__Misc.try_finally in file "src/utils/misc.ml", line 62, characters 10-24
Called from Merlin_utils__Misc.protect_refs.(fun) in file "src/utils/misc.ml", line 82, characters 10-14
Re-raised at Merlin_utils__Misc.protect_refs.(fun) in file "src/utils/misc.ml", line 84, characters 38-45
Called from Ocaml_typing__Persistent_env.without_cmis in file "src/ocaml/typing/persistent_env.ml", line 151, characters 10-109
Called from Merlin_utils__Std.let_ref in file "src/utils/std.ml", line 690, characters 8-12
Re-raised at Merlin_utils__Std.let_ref in file "src/utils/std.ml", line 692, characters 30-39
Called from Dune__exe__New_commands.run in file "src/frontend/ocamlmerlin/new/new_commands.ml", line 65, characters 15-53
Called from Merlin_utils__Std.let_ref in file "src/utils/std.ml", line 690, characters 8-12
Re-raised at Merlin_utils__Std.let_ref in file "src/utils/std.ml", line 692, characters 30-39
Called from Merlin_utils__Misc.try_finally in file "src/utils/misc.ml", line 45, characters 8-15
Re-raised at Merlin_utils__Misc.try_finally in file "src/utils/misc.ml", line 62, characters 10-24
Called from Stdlib__Fun.protect in file "fun.ml", line 33, characters 8-15
Re-raised at Stdlib__Fun.protect in file "fun.ml", line 38, characters 6-52
Called from Merlin_kernel__Mocaml.with_state in file "src/kernel/mocaml.ml", line 18, characters 8-38
Re-raised at Merlin_kernel__Mocaml.with_state in file "src/kernel/mocaml.ml", line 20, characters 42-53
Called from Dune__exe__New_merlin.run.(fun) in file "src/frontend/ocamlmerlin/new/new_merlin.ml", line 101, characters 14-110
If I try to change this to an open variant type ([> `Foo ] option) I get "Destruct not allowed on value_binding" with no crash.