Merge pull request #4569 from BuckleScript/reduandant_bs_string_warning

redundant bs.string warning

Author: bobzhang

jscomp/main/builtin_cmi_datasets.ml

@@ -32,13 +32,15 @@ external isBuffer : 'a -> bool = "Buffer.isBuffer"
 external fromString : string -> t = "Buffer.from"
 [@@bs.val]
 
-external fromStringWithEncoding : string -> ([ `ascii  | `utf8  | `utf16le  | `usc2  | `base64  | `latin1 | `binary  | `hex ] [@bs.string]) -> t = "from"
+type encoding = 
+  [ `ascii  | `utf8  | `utf16le  | `usc2  | `base64  | `latin1 | `binary  | `hex ]  
+external fromStringWithEncoding : string -> encoding -> t = "from"
 [@@bs.val] [@@bs.scope "Buffer"]
 
 external toString : t -> string = "toString"
 [@@bs.send]
 
-external toStringWithEncoding : t -> ([ `ascii  | `utf8  | `utf16le  | `usc2  | `base64  | `latin1 | `binary  | `hex ] [@bs.string]) -> string = "toString"
+external toStringWithEncoding : t -> encoding -> string = "toString"
 [@@bs.send]
 
 external concat : t array -> t = "Buffer.concat"

jscomp/others/node_buffer.ml

@@ -120,20 +120,20 @@ external openSync :
     ] [@bs.string]) ->
   unit = "openSync"  [@@bs.module "fs"]
 
-
+type encoding = 
+  [
+    `hex
+  | `utf8
+  | `ascii
+  | `latin1
+  | `base64
+  | `ucs2
+  | `base64
+  | `binary
+  | `utf16le ]  
 external readFileSync :
   string ->
-  (
-    [
-      `hex
-    | `utf8
-    | `ascii
-    | `latin1
-    | `base64
-    | `ucs2
-    | `base64
-    | `binary
-    | `utf16le ][@bs.string]) ->
+  encoding ->
   string = "readFileSync"
 [@@bs.val] [@@bs.module "fs"]
 
@@ -148,16 +148,7 @@ external existsSync : string -> bool = "existsSync"
 external writeFileSync :
   string ->
   string ->
-  (
-    [ `hex
-    | `utf8
-    | `ascii
-    | `latin1
-    | `base64
-    | `ucs2
-    | `base64
-    | `binary
-    | `utf16le ][@bs.string]) ->
+  encoding ->
   unit = "writeFileSync"
 [@@bs.val] [@@bs.module "fs"]
 

jscomp/others/node_fs.ml

@@ -112,8 +112,14 @@ let map_row_fields_into_strings ptyp_loc
   | `Nothing -> Bs_syntaxerr.err ptyp_loc Invalid_bs_string_type
   | `Null 
   | `NonNull -> 
-    External_arg_spec.Poly_var {has_payload = case = `NonNull ; 
-    descr = if !has_bs_as then Some result else None }
+    let has_payload = case = `NonNull in 
+    let descr = if !has_bs_as then Some result else None in    
+    if not has_payload && descr = None then begin
+      Location.prerr_warning ptyp_loc (Bs_ffi_warning "bs.string is redundant here, you can safely remove it")   
+    end;
+    External_arg_spec.Poly_var 
+      {has_payload  ; 
+       descr  }
 
 let is_enum row_fields = 
   List.for_all (fun (x : Parsetree.row_field) ->