complete unsaved tuples

CHANGELOG.md

@@ -19,6 +19,7 @@
 - Add snippet support in completion items. https://github.com/rescript-lang/rescript-vscode/pull/668
 - Add support from completing polyvariants as values. https://github.com/rescript-lang/rescript-vscode/pull/669
 - Add support for completion in patterns. https://github.com/rescript-lang/rescript-vscode/pull/670
+- Add support for pattern completion of unsaved tuples. https://github.com/rescript-lang/rescript-vscode/pull/679
 
 #### :nail_care: Polish
 

analysis/src/CompletionBackEnd.ml

@@ -1458,6 +1458,25 @@ let rec getCompletionsForContextPath ~full ~opens ~rawOpens ~allFiles ~pos ~env
                })
       | None -> [])
     | None -> [])
+  | CTuple ctxPaths ->
+    (* Turn a list of context paths into a list of type expressions. *)
+    let typeExrps =
+      ctxPaths
+      |> List.map (fun contextPath ->
+             contextPath
+             |> getCompletionsForContextPath ~full ~opens ~rawOpens ~allFiles
+                  ~pos ~env ~exact:true ~scope)
+      |> List.filter_map (fun completionItems ->
+             match completionItems with
+             | {Completion.kind = Value typ} :: _ -> Some typ
+             | _ -> None)
+    in
+    if List.length ctxPaths = List.length typeExrps then
+      [
+        Completion.create ~name:"dummy" ~env
+          ~kind:(Completion.Value (Ctype.newty (Ttuple typeExrps)));
+      ]
+    else []
 
 let getOpens ~debug ~rawOpens ~package ~env =
   if debug && rawOpens <> [] then

analysis/src/CompletionFrontEnd.ml

@@ -260,6 +260,11 @@ let rec exprToContextPath (e : Parsetree.expression) =
     match exprToContextPath e1 with
     | None -> None
     | Some contexPath -> Some (CPApply (contexPath, args |> List.map fst)))
+  | Pexp_tuple exprs ->
+    let exprsAsContextPaths = exprs |> List.filter_map exprToContextPath in
+    if List.length exprs = List.length exprsAsContextPaths then
+      Some (CTuple exprsAsContextPaths)
+    else None
   | _ -> None
 
 let rec getUnqualifiedName txt =

analysis/src/SharedTypes.ml

@@ -549,6 +549,7 @@ module Completable = struct
         lhsLoc: Location.t;
             (** The loc item for the left hand side of the pipe. *)
       }
+    | CTuple of contextPath list
 
   (** Additional context for a pattern completion where needed. *)
   type patternContext = RecordField of {seenFields: string list}
@@ -648,6 +649,10 @@ module Completable = struct
       | CPField (cp, s) -> contextPathToString cp ^ "." ^ str s
       | CPObj (cp, s) -> contextPathToString cp ^ "[\"" ^ s ^ "\"]"
       | CPPipe {contextPath; id} -> contextPathToString contextPath ^ "->" ^ id
+      | CTuple ctxPaths ->
+        "CTuple("
+        ^ (ctxPaths |> List.map contextPathToString |> String.concat ", ")
+        ^ ")"
     in
 
     function

analysis/tests/src/CompletionExpressions.res

@@ -0,0 +1,5 @@
+let s = true
+let f = Some([false])
+
+// switch (s, f) { | }
+//                  ^com

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

@@ -0,0 +1,13 @@
+Complete src/CompletionExpressions.res 3:20
+XXX Not found!
+Completable: Cpattern CTuple(Value[s], Value[f])
+[{
+    "label": "(_, _)",
+    "kind": 12,
+    "tags": [],
+    "detail": "(bool, option<array<bool>>)",
+    "documentation": null,
+    "insertText": "(${1:_}, ${2:_})",
+    "insertTextFormat": 2
+  }]
+