Improve integer literal error messages

Signed-off-by: Nathan Rebours <nathan.p.rebours@gmail.com>

Author: NathanReb

lib/error.ml

@@ -1,20 +1,32 @@
 open Ppxlib
 
+let errorf ~loc message =
+  Location.error_extensionf ~loc "ppx_yojson: %s" message
+
 let unsupported_payload ~loc =
-  Location.error_extensionf ~loc "ppx_yojson: unsupported payload"
+  errorf ~loc "unsupported payload"
 
 let unsupported_record_field ~loc =
-  Location.error_extensionf ~loc "ppx_yojson: unsupported record field"
+  errorf ~loc "unsupported record field"
 
 let too_many_fields_in_record_pattern ~loc =
-  Location.error_extensionf ~loc
-    "ppx_yojson: record patterns with more than 4 fields aren't supported. \
+  errorf ~loc
+    "record patterns with more than 4 fields aren't supported. \
      Consider using ppx_deriving_yojson to handle more complex json objects."
 
 let bad_expr_antiquotation_payload ~loc =
-  Location.error_extensionf ~loc
-    "ppx_yojson: bad antiquotation payload, should be a single expression"
+  errorf ~loc
+    "bad antiquotation payload, should be a single expression"
 
 let bad_pat_antiquotation_payload ~loc =
-  Location.error_extensionf ~loc
-    "ppx_yojson: bad antiquotation payload, should be a pattern"
+  errorf ~loc
+    "bad antiquotation payload, should be a pattern"
+
+let invalid_integer_literal_yojson ~loc =
+  errorf ~loc
+    "invalid interger literal. Integer literal should fit within \
+     an OCaml int or be written in decimal form."
+
+let invalid_integer_literal_ezjsonm ~loc =
+  errorf ~loc
+    "invalid interger literal. Integer literal should fit within an OCaml int."

lib/error.mli

@@ -20,3 +20,9 @@ val bad_expr_antiquotation_payload : loc:Ppxlib.Location.t -> Ppxlib.extension
 
 val bad_pat_antiquotation_payload : loc:Ppxlib.Location.t -> Ppxlib.extension
 (** Use this for bad payload in pattern antiquotation [[%y? ...]]. *)
+
+val invalid_integer_literal_yojson : loc:Ppxlib.Location.t -> Ppxlib.extension
+(** Use this for invalid integer literals in the yojson extension *)
+
+val invalid_integer_literal_ezjsonm : loc:Ppxlib.Location.t -> Ppxlib.extension
+(** Use this for invalid integer literals in the ezjsonm extension *)

lib/expression.ml

@@ -44,15 +44,16 @@ module Ezjsonm_expander : EXPANDER = struct
   include Common
 
   let expand_intlit ~loc:_ ~pexp_loc:loc _ =
-    Ast_builder.Default.pexp_extension ~loc (Error.unsupported_payload ~loc)
+    Ast_builder.Default.pexp_extension ~loc
+      (Error.invalid_integer_literal_ezjsonm ~loc)
 
   let expand_int ~loc ~pexp_loc s =
     match int_of_string_opt s with
     | Some i ->
         [%expr `Float [%e Ast_builder.Default.efloat ~loc (string_of_int i)]]
     | _ ->
         Ast_builder.Default.pexp_extension ~loc:pexp_loc
-          (Error.unsupported_payload ~loc:pexp_loc)
+          (Error.invalid_integer_literal_ezjsonm ~loc:pexp_loc)
 
   let expand_list ~loc exprs =
     expand_list ~loc (fun e -> [%expr `A [%e e]]) exprs
@@ -72,13 +73,13 @@ module Yojson_expander : EXPANDER = struct
     | Some i -> [%expr `Int [%e Ast_builder.Default.eint ~loc i]]
     | None when Integer_const.is_binary s ->
         Ast_builder.Default.pexp_extension ~loc:pexp_loc
-          (Error.unsupported_payload ~loc:pexp_loc)
+          (Error.invalid_integer_literal_yojson ~loc:pexp_loc)
     | None when Integer_const.is_octal s ->
         Ast_builder.Default.pexp_extension ~loc:pexp_loc
-          (Error.unsupported_payload ~loc:pexp_loc)
+          (Error.invalid_integer_literal_yojson ~loc:pexp_loc)
     | None when Integer_const.is_hexadecimal s ->
         Ast_builder.Default.pexp_extension ~loc:pexp_loc
-          (Error.unsupported_payload ~loc:pexp_loc)
+          (Error.invalid_integer_literal_yojson ~loc:pexp_loc)
     | None -> expand_intlit ~loc ~pexp_loc s
 
   let expand_list ~loc exprs =

test/rewriter/errors/run.t

@@ -53,7 +53,8 @@ should trigger errors:
   File "test.ml", line 1, characters 35-59:
   1 | let invalid_hex_literal = [%yojson 0xffffffffffffffffffffff]
                                          ^^^^^^^^^^^^^^^^^^^^^^^^
-  Error: ppx_yojson: unsupported payload
+  Error: ppx_yojson: invalid interger literal. Integer literal should fit
+         within an OCaml int or be written in decimal form.
   [1]
 
 ---------------------------------------
@@ -79,7 +80,8 @@ should trigger errors:
   File "test.ml", line 1, characters 37-79:
   1 | let invalid_octal_literal = [%yojson 0o7777777777777777777777777777777777777777]
                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  Error: ppx_yojson: unsupported payload
+  Error: ppx_yojson: invalid interger literal. Integer literal should fit
+         within an OCaml int or be written in decimal form.
   [1]
 
 --------------------------------------
@@ -105,7 +107,8 @@ should trigger errors:
   File "test.ml", line 1, characters 35-146:
   1 | let invalid_bin_literal = [%yojson 0b1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111]
                                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-  Error: ppx_yojson: unsupported payload
+  Error: ppx_yojson: invalid interger literal. Integer literal should fit
+         within an OCaml int or be written in decimal form.
   [1]
 
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