handle piped fn calls properly

Author: zth

analysis/src/CompletionFrontEnd.ml

@@ -120,7 +120,7 @@ let isExprHole exp =
 
 let findArgCompletables ~(args : arg list) ~endPos ~posBeforeCursor
     ~(contextPath : Completable.contextPath) ~posAfterFunExpr ~charBeforeCursor
-    =
+    ~isPipedExpr =
   let fnHasCursor =
     posAfterFunExpr <= posBeforeCursor && posBeforeCursor < endPos
   in
@@ -132,7 +132,7 @@ let findArgCompletables ~(args : arg list) ~endPos ~posBeforeCursor
         | {label = None} -> allLabels)
       args []
   in
-  let unlabelledCount = ref 0 in
+  let unlabelledCount = ref (if isPipedExpr then 1 else 0) in
   let rec loop args =
     match args with
     | {label = Some labelled; exp} :: rest ->
@@ -635,15 +635,36 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor ~text =
           when Loc.end_ opLoc = posCursor ->
           (* Case foo-> *)
           setPipeResult ~lhs ~id:"" |> ignore
-        | Pexp_apply ({pexp_desc = Pexp_ident {txt = Lident "|."}}, [_; _]) ->
-          ()
-        | Pexp_apply (funExpr, args)
+        | Pexp_apply
+            ( {pexp_desc = Pexp_ident {txt = Lident "|."}},
+              [_; (_, {pexp_desc = Pexp_apply (funExpr, args)})] )
           when (* Normally named arg completion fires when the cursor is right after the expression.
                   E.g in foo(~<---there
                   But it should not fire in foo(~a)<---there *)
                not
                  (Loc.end_ expr.pexp_loc = posCursor
                  && charBeforeCursor = Some ')') ->
+          (* Complete fn argument values and named args when the fn call is piped. E.g. someVar->someFn(<com>). *)
+          let args = extractExpApplyArgs ~args in
+          let argCompletable =
+            match exprToContextPath funExpr with
+            | Some contextPath ->
+              findArgCompletables ~contextPath ~args
+                ~endPos:(Loc.end_ expr.pexp_loc) ~posBeforeCursor
+                ~posAfterFunExpr:(Loc.end_ funExpr.pexp_loc)
+                ~charBeforeCursor ~isPipedExpr:true
+            | None -> None
+          in
+
+          setResultOpt argCompletable
+        | Pexp_apply ({pexp_desc = Pexp_ident {txt = Lident "|."}}, [_; _]) ->
+          (* Ignore any other pipe. *)
+          ()
+        | Pexp_apply (funExpr, args)
+          when not
+                 (Loc.end_ expr.pexp_loc = posCursor
+                 && charBeforeCursor = Some ')') ->
+          (* Complete fn argument values and named args when the fn call is _not_ piped. E.g. someFn(<com>). *)
           let args = extractExpApplyArgs ~args in
           if debug then
             Printf.printf "Pexp_apply ...%s (%s)\n"
@@ -666,7 +687,7 @@ let completionWithParser1 ~currentFile ~debug ~offset ~path ~posCursor ~text =
               findArgCompletables ~contextPath ~args
                 ~endPos:(Loc.end_ expr.pexp_loc) ~posBeforeCursor
                 ~posAfterFunExpr:(Loc.end_ funExpr.pexp_loc)
-                ~charBeforeCursor
+                ~charBeforeCursor ~isPipedExpr:false
             | None -> None
           in
 

analysis/tests/src/CompletionFunctionArguments.res

@@ -67,6 +67,9 @@ let someFnTakingVariant = (
 // let _ = someOtherFn(1, 2, )
 //                          ^com
 
+// let _ = 1->someOtherFn(1, t)
+//                            ^com
+
 // --- BROKEN PARSER CASES ---
 // This below demonstrates an issue when what you're completing is the _last_ labelled argument, and there's a unit application after it. The parser wrongly merges the unit argument as the expression of the labelled argument assignment, where is should really let the trailing unit argument be, and set a %rescript.exprhole as the expression of the assignment, just like it normally does.
 // let _ = someFn(~isOff=, ())

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

@@ -194,9 +194,26 @@ Completable: Cargument Value[someOtherFn]($2)
     "documentation": null
   }]
 
-Complete src/CompletionFunctionArguments.res 71:25
-posCursor:[71:25] posNoWhite:[71:24] Found expr:[71:11->71:30]
-Pexp_apply ...[71:11->71:17] (~isOff71:19->71:24=...[71:27->71:29])
+Complete src/CompletionFunctionArguments.res 69:30
+posCursor:[69:30] posNoWhite:[69:29] Found expr:[69:11->69:31]
+Completable: Cargument Value[someOtherFn]($2=t)
+[{
+    "label": "true",
+    "kind": 4,
+    "tags": [],
+    "detail": "bool",
+    "documentation": null
+  }, {
+    "label": "tLocalVar",
+    "kind": 12,
+    "tags": [],
+    "detail": "bool",
+    "documentation": null
+  }]
+
+Complete src/CompletionFunctionArguments.res 74:25
+posCursor:[74:25] posNoWhite:[74:24] Found expr:[74:11->74:30]
+Pexp_apply ...[74:11->74:17] (~isOff74:19->74:24=...[74:27->74:29])
 Completable: Cargument Value[someFn]($0)
 []