feat: add new case on platform

demo/server/Error.re

@@ -1,7 +1,7 @@
 let handler =
-  Dream.error_template((error, info, suggested) => {
+  Dream.error_template((_error, info, suggested) => {
     let status = Dream.status(suggested);
-    let code = Dream.status_to_int(status);
+    let _code = Dream.status_to_int(status);
     let reason = Dream.status_to_string(status);
     Dream.html(
       ReactDOM.renderToStaticMarkup(

demo/server/dune

@@ -2,7 +2,6 @@
  (name server)
  (enabled_if
   (= %{profile} "dev"))
- (flags :standard -w -26-27) ; browser_only removes code form the server, making this warning necessary
  (libraries
   dream
   demo_shared_native

demo/server/server.re

@@ -6,7 +6,7 @@ let renderToStreamHandler = _ =>
         let%lwt () = Dream.write(response_stream, data);
         Dream.flush(response_stream);
       };
-      let%lwt (stream, _abort) =
+      let%lwt (_stream, _abort) =
         ReactDOM.renderToStream(~pipe, <Document> <Comments /> </Document>);
       Lwt.return();
     },

demo/universal/native/lib/App.re

@@ -90,7 +90,7 @@ let make = () => {
     <Stack gap=8 justify=`start>
       <Title />
       <Hr />
-      <Counter initial=23 />
+      <Counter initial=23 onClick={_ => print_endline("Clicked")} />
     </Stack>
   </Layout>;
 };

demo/universal/native/lib/Counter.re

@@ -1,10 +1,19 @@
-[@warning "-27"];
+let make = (~initial, ~onClick as [@platform js] onClick) => {
+  let (count, [@platform js] setCount) = RR.useStateValue(initial);
 
-let make = (~initial) => {
-  let (state, setCount) = RR.useStateValue(initial);
+  switch%platform (Runtime.platform) {
+  | Server => print_endline("This prints to the server terminal")
+  | Client => print_endline("This prints to the console")
+  };
+
+  [@platform js]
+  let onClick = e => {
+    setCount(count + 1);
+
+    Js.log("This prints to the console");
+    Js.log2("Printing count", count);
 
-  let onClick = _event => {
-    setCount(state + 1);
+    onClick(e);
   };
 
   <div className={Theme.text(Theme.Color.white)}>
@@ -20,9 +29,9 @@ let make = (~initial) => {
           {React.string("Counter")}
         </p>
         <button
-          onClick
-          className="font-mono border-2 py-1 px-2 rounded-lg bg-yellow-950 border-yellow-700 text-yellow-200">
-          {React.string(Int.to_string(state))}
+          className="font-mono border-2 py-1 px-2 rounded-lg bg-yellow-950 border-yellow-700 text-yellow-200"
+          onClick={[@platform js] e => onClick(e)}>
+          {React.string(Int.to_string(count))}
         </button>
       </div>
     </Spacer>
@@ -36,16 +45,16 @@ let make = (~initial) => {
 };
 
 [@react.component]
-let make = (~initial) =>
+let make = (~initial, ~onClick as [@platform js] onClick) =>
   switch%platform (Runtime.platform) {
   | Server =>
     React.Client_component({
       import_module: "Counter",
       import_name: "",
       props: [("initial", React.Json(`Int(initial)))],
-      client: make(~initial),
+      client: make(~initial, ~onClick=_ => ()),
     })
-  | Client => make(~initial)
+  | Client => make(~initial, ~onClick)
   };
 
 let default = make;

demo/universal/native/lib/Noter.re

@@ -31,7 +31,7 @@ let make = (~valueIn3seconds as _) => {
       </p>
       <Note_editor title="Hello" body="World" />
       <Hr />
-      <Counter initial=22 />
+      <Counter initial=22 onClick={_ => print_endline("Clicked")} />
       <Hr />
     </Stack>
   </Layout>;

packages/browser-ppx/ppx.ml

@@ -383,6 +383,35 @@ module Preprocess = struct
         | { psig_desc = Psig_attribute attr; _ } :: rest when is_platform_tag attr.attr_name.txt ->
             if eval_attr attr = `keep then rest else []
         | _ -> List.filter_map apply_config_on_signature_item sigi
+
+      method! expression expr =
+        let expr = super#expression expr in
+        match expr.pexp_desc with
+        | Pexp_ident _ | Pexp_constant _ ->
+            let loc = expr.pexp_loc in
+            [%expr [%ocaml.error "Don't use @platform in Pexp_ident or Pexp_constant"]]
+        | Pexp_let (_, [ { pvb_attributes = attrs; _ } ], body) -> if should_keep attrs = `keep then expr else body
+        | Pexp_fun _ ->
+            if should_keep expr.pexp_attributes = `keep then expr
+            else
+              let rec inner expr' =
+                match expr'.pexp_desc with
+                | Pexp_fun (label, def, _, expression) ->
+                    Builder.pexp_fun ~loc:expr'.pexp_loc label def (Builder.ppat_any ~loc:expr'.pexp_loc)
+                      (inner expression)
+                | _ ->
+                    let loc = expr'.pexp_loc in
+                    [%expr
+                      Runtime.fail_impossible_action_in_ssr_anonymous
+                        [%e Builder.estring ~loc (Astlib.Pprintast.string_of_expression expr)]]
+              in
+              inner expr
+        | _ -> expr
+
+      method! pattern pat =
+        let pat = super#pattern pat in
+        let loc = pat.ppat_loc in
+        if should_keep pat.ppat_attributes = `keep then pat else [%pat? _]
     end
 end
 

packages/browser-ppx/tests/at_platform.t

@@ -124,6 +124,49 @@ Pstr_value
   $ ./standalone.exe -impl input_let.ml -js | ocamlformat - --enable-outside-detected-project --impl
   let x = 42 [@@platform js]
 
+Pexp_let
+
+  $ cat > input_let.ml << EOF
+  > let x =
+  >   let y = 42 [@@platform js] in
+  >   let y = 44 [@@platform native] in
+  >   y
+  > EOF
+
+  $ ./standalone.exe -impl input_let.ml | ocamlformat - --enable-outside-detected-project --impl
+  let x =
+    let y = 44 [@@platform native] in
+    y
+
+  $ ./standalone.exe -impl input_let.ml -js | ocamlformat - --enable-outside-detected-project --impl
+  let x =
+    let y = 42 [@@platform js] in
+    y
+
+Ppat_tuple
+
+  $ cat > input_let.ml << EOF
+  > let (x [@platform native], y [@platform js]) = (42, 44)
+  > EOF
+
+  $ ./standalone.exe -impl input_let.ml | ocamlformat - --enable-outside-detected-project --impl
+  let (x [@platform native]), _ = (42, 44)
+
+  $ ./standalone.exe -impl input_let.ml -js | ocamlformat - --enable-outside-detected-project --impl
+  let _, (y [@platform js]) = (42, 44)
+
+Ppat_var
+
+  $ cat > input_let.ml << EOF
+  > let x ~onClick:((onClick)[@platform js]) = 42
+  > EOF
+
+  $ ./standalone.exe -impl input_let.ml | ocamlformat - --enable-outside-detected-project --impl
+  let x ~onClick:_ = 42
+
+  $ ./standalone.exe -impl input_let.ml -js | ocamlformat - --enable-outside-detected-project --impl
+  let x ~onClick:(onClick [@platform js]) = 42
+
 Pstr_open
 
   $ cat > input_open.ml << EOF

packages/runtime/Runtime.ml

@@ -9,6 +9,40 @@ let fail_impossible_action_in_ssr fn =
 
 Here's the raw callstack:
 
+%s
+|}
+      fn raw_callstack
+  in
+  raise (Impossible_in_ssr (Printf.sprintf {|'%s' shouldn't run on the server|} fn))
+
+let fail_impossible_action_in_ssr_anonymous fn =
+  let backtrace = Printexc.get_callstack 8 in
+  let raw_callstack = Printexc.raw_backtrace_to_string backtrace in
+  let () =
+    Printf.printf
+      {|This function should only run on the client. Make sure you aren't accidentally calling this function in a server-side context.
+
+Function: %s
+
+Here's the raw callstack:
+
+%s
+|}
+      fn raw_callstack
+  in
+  raise (Impossible_in_ssr (Printf.sprintf {|'%s' shouldn't run on the server|} fn))
+
+let fail_impossible_action_in_ssr_anonymous fn =
+  let backtrace = Printexc.get_callstack 8 in
+  let raw_callstack = Printexc.raw_backtrace_to_string backtrace in
+  let () =
+    Printf.printf
+      {|This function should only run on the client. Make sure you aren't accidentally calling this function in a server-side context.
+
+Function: %s
+
+Here's the raw callstack:
+
 %s
 |}
       fn raw_callstack

packages/runtime/Runtime.mli

@@ -6,6 +6,7 @@ exception Impossible_in_ssr of string
 (** Exception to throw when operations aren't meant to be running on native, mostly used by browser_ppx or ReactDOM *)
 
 val fail_impossible_action_in_ssr : string -> 'a
+val fail_impossible_action_in_ssr_anonymous : string -> 'a
 
 type platform =
   | Server

packages/server-reason-react-ppx/server_reason_react_ppx.ml

@@ -449,7 +449,7 @@ let rec transform_function_with_warning expression =
       { expression with pexp_desc = Pexp_sequence (wrapperExpression, exp) }
   | _ -> expression
 
-let transofrm_last_expression expr fn =
+let transform_last_expression expr fn =
   let rec inner expr =
     match expr.pexp_desc with
     | Pexp_sequence (expr, sequence) -> pexp_sequence ~loc:expr.pexp_loc expr (inner sequence)
@@ -475,7 +475,7 @@ let make_value_binding binding wrapping =
   (* Append key argument since we want to allow users of this component to set key
      (and assign it to _ since it shouldn't be used) *)
   let body_expression =
-    pexp_fun ~loc:ghost_loc key_arg default_value key_pattern (transofrm_last_expression binding_expr wrapping)
+    pexp_fun ~loc:ghost_loc key_arg default_value key_pattern (transform_last_expression binding_expr wrapping)
   in
   Ast_helper.Vb.mk ~loc name body_expression