Suggest field name in completion of options in record fields

CHANGELOG.md

@@ -15,6 +15,7 @@
 #### :rocket: New Feature
 
 - Docstring template Code Action. https://github.com/rescript-lang/rescript-vscode/pull/764
+- Add `Some(fieldName)` case when completing in a pattern with an option on a record field. https://github.com/rescript-lang/rescript-vscode/pull/766
 
 ## 1.16.0
 

analysis/src/CompletionBackEnd.ml

@@ -1235,13 +1235,26 @@ let rec completeTypedValue ~full ~prefix ~completionContext ~mode
                    | Some insertText -> Some ("Some(" ^ insertText ^ ")"));
                })
     in
-    [
-      Completion.create "None" ~kind:(kindFromInnerType t) ~env;
+    let noneCase = Completion.create "None" ~kind:(kindFromInnerType t) ~env in
+    let someAnyCase =
       Completion.createWithSnippet ~name:"Some(_)" ~kind:(kindFromInnerType t)
-        ~env ~insertText:"Some(${1:_})" ();
-    ]
-    @ expandedCompletions
-    |> filterItems ~prefix
+        ~env ~insertText:"Some(${1:_})" ()
+    in
+    let completions =
+      match completionContext with
+      | Some (Completable.CameFromRecordField fieldName) ->
+        [
+          Completion.createWithSnippet
+            ~name:("Some(" ^ fieldName ^ ")")
+            ~kind:(kindFromInnerType t) ~env
+            ~insertText:("Some(${1:" ^ fieldName ^ "})")
+            ();
+          someAnyCase;
+          noneCase;
+        ]
+      | _ -> [noneCase; someAnyCase]
+    in
+    completions @ expandedCompletions |> filterItems ~prefix
   | Tuple (env, exprs, typ) ->
     let numExprs = List.length exprs in
     [
@@ -1279,7 +1292,7 @@ let rec completeTypedValue ~full ~prefix ~completionContext ~mode
                    (Field (field, TypeUtils.extractedTypeToString extractedType))
                  ~env)
       |> filterItems ~prefix
-    | None ->
+    | _ ->
       if prefix = "" then
         [
           Completion.createWithSnippet ~name:"{}"
@@ -1304,7 +1317,7 @@ let rec completeTypedValue ~full ~prefix ~completionContext ~mode
              Completion.create field.fname.txt ~kind:(Label "Inline record")
                ?deprecated:field.deprecated ~env)
       |> filterItems ~prefix
-    | None ->
+    | _ ->
       if prefix = "" then
         [
           Completion.createWithSnippet ~name:"{}"

analysis/src/SharedTypes.ml

@@ -529,7 +529,12 @@ module Completable = struct
     | Optional of string
 
   (** Additional context for nested completion where needed. *)
-  type nestedContext = RecordField of {seenFields: string list}
+  type nestedContext =
+    | RecordField of {seenFields: string list}
+        (** Completing for a record field, and we already saw the following fields... *)
+    | CameFromRecordField of string
+        (** We just came from this field (we leverage use this for better
+            completion names etc) *)
 
   type nestedPath =
     | NTupleItem of {itemNum: int}

analysis/src/TypeUtils.ml

@@ -257,10 +257,20 @@ let extractTypeFromResolvedType (typ : Type.t) ~env ~full =
     | None -> None
     | Some t -> t |> extractType ~env ~package:full.package)
 
+(** The context we just came from as we resolve the nested structure. *)
+type ctx = Rfield of string  (** A record field of name *)
+
 (** This moves through a nested path via a set of instructions, trying to resolve the type at the end of the path. *)
-let rec resolveNested (typ : completionType) ~env ~full ~nested =
+let rec resolveNested ~env ~full ~nested ?ctx (typ : completionType) =
   match nested with
-  | [] -> Some (typ, env, None)
+  | [] ->
+    Some
+      ( typ,
+        env,
+        match ctx with
+        | None -> None
+        | Some (Rfield fieldName) ->
+          Some (Completable.CameFromRecordField fieldName) )
   | patternPath :: nested -> (
     match (patternPath, typ) with
     | Completable.NTupleItem {itemNum}, Tuple (env, tupleItems, _) -> (
@@ -283,7 +293,7 @@ let rec resolveNested (typ : completionType) ~env ~full ~nested =
         typ
         |> extractType ~env ~package:full.package
         |> Utils.Option.flatMap (fun typ ->
-               typ |> resolveNested ~env ~full ~nested))
+               typ |> resolveNested ~ctx:(Rfield fieldName) ~env ~full ~nested))
     | NRecordBody {seenFields}, Trecord {env; definition = `TypeExpr typeExpr}
       ->
       typeExpr

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

@@ -191,11 +191,13 @@ ContextPath CArgument Value[fnTakingRecord]($0)
 ContextPath Value[fnTakingRecord]
 Path fnTakingRecord
 [{
-    "label": "None",
+    "label": "Some(nested)",
     "kind": 12,
     "tags": [],
     "detail": "otherRecord",
-    "documentation": null
+    "documentation": null,
+    "insertText": "Some(${1:nested})",
+    "insertTextFormat": 2
   }, {
     "label": "Some(_)",
     "kind": 12,
@@ -204,6 +206,12 @@ Path fnTakingRecord
     "documentation": null,
     "insertText": "Some(${1:_})",
     "insertTextFormat": 2
+  }, {
+    "label": "None",
+    "kind": 12,
+    "tags": [],
+    "detail": "otherRecord",
+    "documentation": null
   }, {
     "label": "Some({})",
     "kind": 12,
@@ -298,21 +306,8 @@ Path fnTakingRecord
     "tags": [],
     "detail": "One\n\ntype someVariant = One | Two | Three(int, string)",
     "documentation": null,
-    "sortText": "A One",
     "insertText": "One",
     "insertTextFormat": 2
-  }, {
-    "label": "Obj",
-    "kind": 9,
-    "tags": [],
-    "detail": "file module",
-    "documentation": null
-  }, {
-    "label": "Objects",
-    "kind": 9,
-    "tags": [],
-    "detail": "file module",
-    "documentation": null
   }]
 
 Complete src/CompletionExpressions.res 56:57
@@ -616,11 +611,13 @@ ContextPath CArgument Value[fnTakingRecordWithOptVariant]($0)
 ContextPath Value[fnTakingRecordWithOptVariant]
 Path fnTakingRecordWithOptVariant
 [{
-    "label": "None",
+    "label": "Some(someVariant)",
     "kind": 12,
     "tags": [],
     "detail": "someVariant",
-    "documentation": null
+    "documentation": null,
+    "insertText": "Some(${1:someVariant})",
+    "insertTextFormat": 2
   }, {
     "label": "Some(_)",
     "kind": 12,
@@ -629,6 +626,12 @@ Path fnTakingRecordWithOptVariant
     "documentation": null,
     "insertText": "Some(${1:_})",
     "insertTextFormat": 2
+  }, {
+    "label": "None",
+    "kind": 12,
+    "tags": [],
+    "detail": "someVariant",
+    "documentation": null
   }, {
     "label": "Some(One)",
     "kind": 4,