test: reproduce issue #1748

CHANGES.md

@@ -3,8 +3,11 @@ merlin NEXT_VERSION
 
   + merlin binary
     - destruct: Removal of residual patterns (#1737, fixes #1560)
-    - Do not erase fields' names when destructing punned record fields (#1734, 
+    - Do not erase fields' names when destructing punned record fields (#1734,
       fixes #1661)
+    - locate: fix an issue when locating the module ident in
+      an[open_description]. Merlin was using the wrong environment due to the
+      absence of a node representing the ident. (#1750, fixes #1748)
 
 merlin 4.14
 ===========

src/ocaml/merlin_specific/browse_raw.ml

@@ -688,7 +688,21 @@ let of_node = function
   | Module_binding_name _ -> id_fold
   | Module_declaration_name _ -> id_fold
   | Module_type_declaration_name _ -> id_fold
-  | Open_description _ -> id_fold
+  | Open_description od ->
+    (* We synthezise a [module_ident] node from the [open] infos so that Merlin
+      does not use the open resulting environment to answer queries about the
+      module ident. Without this synthetic node Merlin would select the entire
+      open node when the cursor is hover the ident. See issue #1748 *)
+    let path, lid = od.open_expr in
+    let m = {
+        mod_desc = Tmod_ident (path, lid);
+        mod_loc = lid.loc;
+        mod_type = Mty_ident path;
+        mod_env = Env.empty;
+        mod_attributes = [];
+      }
+    in
+    app (Module_expr m)
   | Open_declaration od ->
     app (Module_expr od.open_expr)
   | Include_declaration i ->

tests/test-dirs/locate/ambiguity/homonyms.t/bar.ml

@@ -0,0 +1,3 @@
+module Import = struct
+  type hello = string
+end

tests/test-dirs/locate/ambiguity/homonyms.t/foo.ml

@@ -0,0 +1 @@
+open! Import

tests/test-dirs/locate/ambiguity/homonyms.t/foo.mli

@@ -0,0 +1 @@
+open! Import

tests/test-dirs/locate/ambiguity/homonyms.t/import.ml

@@ -0,0 +1 @@
+include Bar

tests/test-dirs/locate/ambiguity/homonyms.t/run.t

@@ -0,0 +1,39 @@
+This test reproduces issue #1748
+
+  $ cat bar.ml
+  module Import = struct
+    type hello = string
+  end
+
+  $ cat import.ml
+  include Bar
+
+  $ cat foo.mli
+  open! Import
+
+  $ cat foo.ml
+  open! Import
+
+  $ $OCAMLC -c -bin-annot bar.ml import.ml foo.mli foo.ml
+
+Merlin correctly jump to the Import module. Not the one in Bar.
+  $ $MERLIN single locate -position 1:10 -look-for implementation \
+  >  -filename foo.ml < foo.ml | jq '.value'
+  {
+    "file": "$TESTCASE_ROOT/import.ml",
+    "pos": {
+      "line": 1,
+      "col": 0
+    }
+  }
+
+Same in the mli:
+  $ $MERLIN single locate -position 1:10 -look-for implementation \
+  > -filename foo.mli < foo.mli | jq '.value'
+  {
+    "file": "$TESTCASE_ROOT/import.ml",
+    "pos": {
+      "line": 1,
+      "col": 0
+    }
+  }