Print @as names and external strings as ReScript string literals

changes/printed-string-escaping.fix.md

@@ -0,0 +1 @@
+- Print the `@as` names of fields and constructors and the strings of externals as they are written, so that non-ASCII letters are no longer turned into escapes that read back as other characters in error messages, hover and generated interfaces.

compiler/ml/printtyp.ml

@@ -945,7 +945,8 @@ and tree_of_constructor ?printing_context ~layout ~position cd =
       let as_annotation = function
         | Variant_runtime.Null -> "@as(null)"
         | Undefined -> "@as(undefined)"
-        | String s -> Printf.sprintf "@as(%S)" s
+        | String s ->
+          Printf.sprintf "@as(\"%s\")" (String_literal.encode_js_string s)
         | Int i -> Printf.sprintf "@as(%d)" i
         | Float f -> Printf.sprintf "@as(%s)" f
         | Bool b -> Printf.sprintf "@as(%b)" b

compiler/syntax/src/res_outcome_printer.ml

@@ -41,6 +41,9 @@ let collect_arrow_args (out_type : Outcometree.out_type) =
   | Otyp_arrow (args, ret) -> (args, ret)
   | _ -> ([], out_type)
 
+let print_string_literal_doc s =
+  Doc.text ("\"" ^ String_literal.encode_js_string s ^ "\"")
+
 let rec collect_functor_args (out_module_type : Outcometree.out_module_type)
     args =
   match out_module_type with
@@ -398,7 +401,12 @@ and print_record_decl_row_doc (name, runtime_name, mut, opt, arg) =
        [
          (match runtime_name with
          | Some runtime_name ->
-           Doc.text ("@as(\"" ^ String.escaped runtime_name ^ "\") ")
+           Doc.concat
+             [
+               Doc.text "@as(";
+               print_string_literal_doc runtime_name;
+               Doc.text ") ";
+             ]
          | None -> Doc.nil);
          (if mut then Doc.text "mutable " else Doc.nil);
          Printer.print_ident_like ~allow_uident:false name;
@@ -454,7 +462,6 @@ let print_type_parameter_doc (typ, (co, cn)) =
 
 (* Print a digested FFI declaration as the surface attributes the user
    wrote; the stored form is the declaration itself. *)
-let print_string_literal_doc s = Doc.text ("\"" ^ String.escaped s ^ "\"")
 
 let print_inline_const_doc (c : External_ffi_types.inline_const) =
   match c with

tests/build_tests/super_errors/expected/as_names_printed_as_written.res.expected

@@ -0,0 +1,21 @@
+
+  We've found a bug for you!
+  /.../fixtures/as_names_printed_as_written.res:5:5-7:1
+
+  3 │ module M: {
+  4 │   type t = | @as("é") A({@as("prénom") name: string}) | @as("a\"b") B
+  5 │ } = {
+  6 │   type t = | @as("é") A({@as("prénom") name: int}) | @as("a\"b") B
+  7 │ }
+  8 │ 
+
+  Signature mismatch:
+
+  Actual declaration (/.../fixtures/as_names_printed_as_written.res:6:3-66):
+    type t = @as("é") A({@as("prénom") name: int}) | @as("a\"b") B
+
+  Expected declaration (/.../fixtures/as_names_printed_as_written.res:4:3-69):
+    type t = @as("é") A({@as("prénom") name: string}) | @as("a\"b") B
+
+  The records of constructor A differ:
+    The types for field name are not equal.

tests/build_tests/super_errors/expected/external_strings_printed_as_written.res.expected

@@ -0,0 +1,19 @@
+
+  We've found a bug for you!
+  /.../fixtures/external_strings_printed_as_written.res:5:5-8:1
+
+  3 │   @module("ünïcode") @scope("ëxtra")
+  4 │   external f: int => int = "f"
+  5 │ } = {
+  6 │   @module("ünïcode") @scope("ëxtra")
+  7 │   external f: string => int = "f"
+  8 │ }
+  9 │ 
+
+  Signature mismatch:
+
+  Actual declaration (/.../fixtures/external_strings_printed_as_written.res:6:3-7:33):
+    @val @module("ünïcode") @scope("ëxtra") external f: string => int = "f"
+
+  Expected declaration (/.../fixtures/external_strings_printed_as_written.res:3:3-4:30):
+    @val @module("ünïcode") @scope("ëxtra") external f: int => int = "f"

tests/build_tests/super_errors/fixtures/as_names_printed_as_written.res

@@ -0,0 +1,7 @@
+// The @as names of constructors and fields print as they are written in
+// source, non-ASCII letters and quotes included
+module M: {
+  type t = | @as("é") A({@as("prénom") name: string}) | @as("a\"b") B
+} = {
+  type t = | @as("é") A({@as("prénom") name: int}) | @as("a\"b") B
+}

tests/build_tests/super_errors/fixtures/external_strings_printed_as_written.res

@@ -0,0 +1,8 @@
+// The strings of a printed external print as they are written in source
+module M: {
+  @module("ünïcode") @scope("ëxtra")
+  external f: int => int = "f"
+} = {
+  @module("ünïcode") @scope("ëxtra")
+  external f: string => int = "f"
+}