poc complete pattern of function parameter

Author: zth

analysis/src/CompletionFrontEnd.ml

@@ -456,6 +456,7 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor ~text =
     scope :=
       !scope |> Scope.addModule ~name:md.pmd_name.txt ~loc:md.pmd_name.loc
   in
+  (* TODO: Can get rid of setLookingForPat soon *)
   let setLookingForPat ctxPath = lookingForPat := Some ctxPath in
   let inJsxContext = ref false in
 
@@ -1032,8 +1033,12 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor ~text =
           (match defaultExpOpt with
           | None -> ()
           | Some defaultExp -> iterator.expr iterator defaultExp);
-          scopePattern ?contextPath:!currentCtxPath pat;
+          (match !currentCtxPath with
+          | None -> ()
+          | Some ctxPath -> setLookingForPat ctxPath);
           completePattern pat;
+          unsetLookingForPat ();
+          scopePattern ?contextPath:!currentCtxPath pat;
           iterator.pat iterator pat;
           iterator.expr iterator e;
           scope := oldScope;

analysis/tests/src/CompletionInferValues.res

@@ -98,3 +98,11 @@ type otherNestedRecord = {someRecord: someRecord, someTuple: (someVariant, int)}
 // Same as above, but follow in switch case
 // let x: otherNestedRecord; switch x { | {someTuple} => let (_, someInt) = someTuple; someInt->toS }
 //                                                                                                 ^com
+
+let fnWithRecordCallback = (cb: someRecord => unit) => {
+  let _ = cb
+}
+
+// Complete pattern of function parameter
+// fnWithRecordCallback(({}) => {()})
+//                        ^com

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

@@ -319,3 +319,24 @@ Completable: Cpath Value[someInt]->toS
     "documentation": {"kind": "markdown", "value": "\n  Converts a given `int` to a `string`. Uses the JavaScript `String` constructor under the hood.\n\n  ```res example\n  Js.log(Belt.Int.toString(1) === \"1\") /* true */\n  ```\n"}
   }]
 
+Complete src/CompletionInferValues.res 105:26
+posCursor:[105:26] posNoWhite:[105:25] Found expr:[105:3->105:37]
+Pexp_apply ...[105:3->105:23] (...[105:24->105:36])
+posCursor:[105:26] posNoWhite:[105:25] Found expr:[105:24->105:36]
+posCursor:[105:26] posNoWhite:[105:25] Found pattern:[105:25->105:27]
+posCursor:[105:26] posNoWhite:[105:25] Found pattern:[105:25->105:27]
+Completable: Cpattern CArgument CArgument Value[fnWithRecordCallback]($0)($0)->recordBody
+[{
+    "label": "name",
+    "kind": 5,
+    "tags": [],
+    "detail": "name: string\n\nsomeRecord",
+    "documentation": null
+  }, {
+    "label": "age",
+    "kind": 5,
+    "tags": [],
+    "detail": "age: int\n\nsomeRecord",
+    "documentation": null
+  }]
+