Jump to incorrect module

[liam923]

Hi, I've recently joined the Jane Street compiler team. We've had a user report a bug, which I've included reproduction steps for below. Essentially, there is an import.ml file, which includes another module named Import. This leads to a Import.Import module existing in scope. When another file contains open Import, Merlin traces the location of Import to the correct location when the file is a .ml file but incorrectly traces to Import.Import when the file is a .mli file.

Reproduction Steps

1. Download and extract jump_to_wrong_import.tar.gz
2. cd into the jump_to_wrong_import directory
3. dune build
4. ocamlmerlin single locate -position 1:10 -look-for implementation -filename lib/foo.mli < lib/foo.mli

This gives:

{"class":"return","value":{"file":"/path/to/jump_to_wrong_import/lib/bar.ml","pos":{"line":1,"col":0}},"notifications":[],"timing":{"clock":20,"cpu":4,"query":2,"pp":0,"reader":0,"ppx":0,"typer":2,"error":0},"heap_mbytes":1,"cache":{"reader_phase":"miss","ppx_phase":"miss","typer":"miss","cmt":{"hit":1,"miss":3},"cmi":{"hit":0,"miss":4}},"query_num":0}

Compare this to ocamlmerlin single locate -position 1:10 -look-for implementation -filename lib/foo.ml < lib/foo.ml, which gives the expected:

{"class":"return","value":{"file":"/path/to/jump_to_wrong_import/lib/import.ml","pos":{"line":1,"col":0}},"notifications":[],"timing":{"clock":18,"cpu":4,"query":2,"pp":0,"reader":0,"ppx":0,"typer":2,"error":0},"heap_mbytes":1,"cache":{"reader_phase":"miss","ppx_phase":"miss","typer":"miss","cmt":{"hit":1,"miss":2},"cmi":{"hit":0,"miss":4}},"query_num":0}

Version info:

• ocamlmerlin built from d5dd40e70eceabe7f9c7c413141430e57e44ded4 (up-to-date master as of the time of posting this)
• dune 3.14.2
• ocaml 4.14.2

Full opam env:

$ opam list -i --columns="name,version"
# Packages matching: installed
# Name                # Version
astring               0.8.5
base                  v0.16.3
base-bigarray         base
base-bytes            base
base-threads          base
base-unix             base
camlp-streams         5.0.1
chrome-trace          3.14.2
cmdliner              1.2.0
conf-bash             1
cppo                  1.6.9
csexp                 1.5.2
dune                  3.14.2
dune-build-info       3.14.2
dune-configurator     3.14.2
dune-rpc              3.14.2
dyn                   3.14.2
either                1.0.0
fiber                 3.7.0
fix                   20230505
fpath                 0.7.3
menhir                20201216
menhirLib             20201216
menhirSdk             20201216
merlin-lib            4.14-414
ocaml                 4.14.2
ocaml-base-compiler   4.14.2
ocaml-config          2
ocaml-lsp-server      1.17.0
ocaml-options-vanilla 1
ocaml-version         3.6.5
ocamlbuild            0.14.3
ocamlc-loc            3.14.2
ocamlfind             1.9.6
ocamlformat           0.26.1
ocamlformat-lib       0.26.1
ocamlformat-rpc-lib   0.26.1
ocp-indent            1.8.1
ordering              3.14.2
pp                    1.2.0
ppx_yojson_conv_lib   v0.16.0
re                    1.11.0
result                1.5
seq                   base
sexplib0              v0.16.0
spawn                 v0.15.1
stdio                 v0.16.0
stdune                3.14.2
topkg                 1.0.7
uucp                  15.1.0
uuseg                 15.1.0
uutf                  1.0.3
xdg                   3.14.2
yojson                2.1.2