Fix nested signature help

CHANGELOG.md

@@ -30,6 +30,7 @@
 #### :bug: Bug Fix
 
 - Highlight `catch` like a keyword https://github.com/rescript-lang/rescript-vscode/pull/677
+- Make signature help work in calls nested inside of other calls. https://github.com/rescript-lang/rescript-vscode/pull/687
 
 ## v1.10.0
 

analysis/src/SignatureHelp.ml

@@ -179,10 +179,19 @@ let signatureHelp ~path ~pos ~currentFile ~debug =
       let supportsMarkdownLinks = true in
       let foundFunctionApplicationExpr = ref None in
       let setFound r =
-        if !foundFunctionApplicationExpr = None then
+        (* Because we want to handle both piped and regular function calls, and in
+           the case of piped calls the iterator will process both the pipe and the
+           regular call (even though it's piped), we need to ensure that we don't
+           re-save the same expression (but unpiped, even though it's actually piped). *)
+        match (!foundFunctionApplicationExpr, r) with
+        | Some (_, alreadyFoundExp, _), (_, newExp, _)
+          when alreadyFoundExp.Parsetree.pexp_loc <> newExp.Parsetree.pexp_loc
+          ->
           foundFunctionApplicationExpr := Some r
+        | None, _ -> foundFunctionApplicationExpr := Some r
+        | Some _, _ -> ()
       in
-      let searchForArgWithCursor ~isPipeExpr ~args ~exp =
+      let searchForArgWithCursor ~isPipeExpr ~args =
         let extractedArgs = extractExpApplyArgs ~args in
         let argAtCursor =
           let firstArgIndex = if isPipeExpr then 1 else 0 in
@@ -246,7 +255,7 @@ let signatureHelp ~path ~pos ~currentFile ~debug =
                  else 0))
           | v -> v
         in
-        setFound (argAtCursor, exp, extractedArgs)
+        (argAtCursor, extractedArgs)
       in
       let expr (iterator : Ast_iterator.iterator) (expr : Parsetree.expression)
           =
@@ -269,7 +278,10 @@ let signatureHelp ~path ~pos ~currentFile ~debug =
           when pexp_loc
                |> CursorPosition.classifyLoc ~pos:posBeforeCursor
                == HasCursor ->
-          searchForArgWithCursor ~isPipeExpr:true ~args ~exp
+          let argAtCursor, extractedArgs =
+            searchForArgWithCursor ~isPipeExpr:true ~args
+          in
+          setFound (argAtCursor, exp, extractedArgs)
         (* Look for applying idents, like someIdent(...) *)
         | {
          pexp_desc = Pexp_apply (({pexp_desc = Pexp_ident _} as exp), args);
@@ -278,7 +290,10 @@ let signatureHelp ~path ~pos ~currentFile ~debug =
           when pexp_loc
                |> CursorPosition.classifyLoc ~pos:posBeforeCursor
                == HasCursor ->
-          searchForArgWithCursor ~isPipeExpr:false ~args ~exp
+          let argAtCursor, extractedArgs =
+            searchForArgWithCursor ~isPipeExpr:false ~args
+          in
+          setFound (argAtCursor, exp, extractedArgs)
         | _ -> ());
         Ast_iterator.default_iterator.expr iterator expr
       in

analysis/tests/src/SignatureHelp.res

@@ -68,3 +68,9 @@ let fn = (age: int, name: string, year: int) => {
 
 // let _ = fn(12, "hello", )
 //                        ^she
+
+// let _ = fn({ iAmSoSpecial() })
+//                           ^she
+
+// let _ = fn({ iAmSoSpecial({ someFunc() }) })
+//                                      ^she

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

@@ -266,3 +266,45 @@ extracted params:
   "activeParameter": 2
 }
 
+Signature help src/SignatureHelp.res 71:29
+posCursor:[71:28] posNoWhite:[71:27] Found expr:[71:11->71:33]
+Pexp_apply ...[71:11->71:13] (...[71:16->71:30])
+posCursor:[71:28] posNoWhite:[71:27] Found expr:[71:16->71:30]
+Pexp_apply ...[71:16->71:28] (...[71:29->71:30])
+posCursor:[71:28] posNoWhite:[71:27] Found expr:[71:16->71:28]
+Pexp_ident iAmSoSpecial:[71:16->71:28]
+argAtCursor: unlabelled<0>
+extracted params: 
+[string]
+{
+  "signatures": [{
+    "label": "string => unit",
+    "parameters": [{"label": [0, 6], "documentation": {"kind": "markdown", "value": "```rescript\nstring\n```"}}]
+  }],
+  "activeSignature": 0,
+  "activeParameter": 0
+}
+
+Signature help src/SignatureHelp.res 74:40
+posCursor:[74:39] posNoWhite:[74:38] Found expr:[74:11->74:47]
+Pexp_apply ...[74:11->74:13] (...[74:16->74:44])
+posCursor:[74:39] posNoWhite:[74:38] Found expr:[74:16->74:44]
+Pexp_apply ...[74:16->74:28] (...[74:31->74:41])
+posCursor:[74:39] posNoWhite:[74:38] Found expr:[74:31->74:41]
+Pexp_apply ...[74:31->74:39] (...[74:40->74:41])
+posCursor:[74:39] posNoWhite:[74:38] Found expr:[74:31->74:39]
+Pexp_ident someFunc:[74:31->74:39]
+argAtCursor: unlabelled<0>
+extracted params: 
+[(
+  int, ~two: string=?, ~three: unit => unit, ~four: someVariant, unit]
+{
+  "signatures": [{
+    "label": "(\n  int,\n  ~two: string=?,\n  ~three: unit => unit,\n  ~four: someVariant,\n  unit,\n) => unit",
+    "parameters": [{"label": [0, 7], "documentation": {"kind": "markdown", "value": "```rescript\nint\n```"}}, {"label": [11, 25], "documentation": {"kind": "markdown", "value": "```rescript\noption<string>\n```"}}, {"label": [29, 49], "documentation": {"kind": "markdown", "value": ""}}, {"label": [53, 71], "documentation": {"kind": "markdown", "value": "```rescript\nsomeVariant\n```\n```rescript\ntype someVariant = One | Two | Three\n```\nGo to: [Type definition](command:rescript-vscode.go_to_location?%5B%22SignatureHelp.res%22%2C0%2C0%5D)"}}, {"label": [75, 79], "documentation": {"kind": "markdown", "value": "```rescript\nint\n```"}}],
+    "documentation": {"kind": "markdown", "value": " Does stuff. "}
+  }],
+  "activeSignature": 0,
+  "activeParameter": 0
+}
+