Support type instantiation in the presence of aliasing.

Author: cristianoc

analysis/src/CompletionBackEnd.ml

@@ -1044,7 +1044,11 @@ let rec extractRecordType ~env ~package (t : Types.type_expr) =
                {field with typ = fieldTyp})
       in
       Some (env, fields, typ)
-    | Some (env, {item = {decl = {type_manifest = Some t1}}}) ->
+    | Some
+        ( env,
+          {item = {decl = {type_manifest = Some t1; type_params = typeParams}}}
+        ) ->
+      let t1 = t1 |> instantiateType ~typeParams ~typeArgs in
       extractRecordType ~env ~package t1
     | _ -> None)
   | _ -> None

analysis/tests/src/expected/Hover.res.txt

@@ -138,11 +138,23 @@ Complete src/Hover.res 180:16
 posCursor:[180:16] posNoWhite:[180:15] Found expr:[180:5->180:16]
 Pexp_field [180:5->180:15] _:[185:0->180:16]
 Completable: Cpath Value[y1].content.""
-[]
+[{
+    "label": "age",
+    "kind": 5,
+    "tags": [],
+    "detail": "age: int\n\ntype bar = {age: int}",
+    "documentation": null
+  }]
 
 Complete src/Hover.res 183:16
 posCursor:[183:16] posNoWhite:[183:15] Found expr:[183:5->183:16]
 Pexp_field [183:5->183:15] _:[185:0->183:16]
 Completable: Cpath Value[y2].content.""
-[]
+[{
+    "label": "age",
+    "kind": 5,
+    "tags": [],
+    "detail": "age: int\n\ntype bar = {age: int}",
+    "documentation": null
+  }]