diff --git a/src/passes/1-parser/cameligo/ParErr.ml b/src/passes/1-parser/cameligo/ParErr.ml
index 98dd3439d..7debe48ef 100644
--- a/src/passes/1-parser/cameligo/ParErr.ml
+++ b/src/passes/1-parser/cameligo/ParErr.ml
@@ -46,7 +46,7 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 33 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 459 ->
+    | 460 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 27 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -68,9 +68,9 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 133 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 372 ->
+    | 373 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 374 ->
+    | 375 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 134 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -80,7 +80,7 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 153 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 373 ->
+    | 374 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 63 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -144,85 +144,83 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 156 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 462 ->
+    | 463 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 464 ->
+    | 465 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 216 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 241 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 218 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 220 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 214 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 225 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 254 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 255 ->
+    | 217 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 242 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 263 ->
+    | 219 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 227 ->
+    | 221 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 215 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 226 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 255 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 256 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 243 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 264 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 228 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 257 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 265 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 267 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 269 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 271 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 273 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 192 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 258 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 284 ->
+    | 266 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 287 ->
+    | 268 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 244 ->
+    | 270 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 292 ->
+    | 272 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 261 ->
+    | 274 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 192 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 259 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 285 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 288 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 245 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 293 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 262 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 160 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 164 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 428 ->
+    | 429 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 331 ->
+    | 332 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 312 ->
+    | 313 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 430 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 314 ->
+    | 431 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 315 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 316 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 431 ->
+    | 317 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 444 ->
+    | 432 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 445 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 432 ->
+    | 446 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 433 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -234,19 +232,19 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 437 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 439 ->
+    | 438 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 327 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 329 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 333 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 330 ->
+    | 440 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 328 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 339 ->
+    | 330 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 334 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 331 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 329 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 340 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -258,23 +256,25 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 344 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 366 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 345 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 347 ->
+    | 367 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 440 ->
+    | 346 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 442 ->
+    | 348 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 446 ->
+    | 441 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 429 ->
+    | 443 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 311 ->
+    | 447 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 427 ->
+    | 430 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 312 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 428 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 165 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -286,23 +286,23 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 163 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 447 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 449 ->
+    | 448 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 450 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 166 ->
+    | 451 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 234 ->
+    | 166 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 235 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 238 ->
+    | 236 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 239 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 424 ->
+    | 240 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 425 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 170 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -310,31 +310,29 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 172 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 417 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 418 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 421 ->
+    | 419 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 422 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 174 ->
+    | 423 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 303 ->
+    | 174 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 304 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 404 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 411 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 403 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 305 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 307 ->
+    | 405 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 319 ->
+    | 412 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 404 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 306 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 308 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 320 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -350,19 +348,19 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 326 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 377 ->
+    | 327 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 378 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 380 ->
+    | 379 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 334 ->
+    | 381 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 309 ->
+    | 335 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 306 ->
+    | 310 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 394 ->
+    | 307 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 395 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -374,11 +372,13 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 399 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 407 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 400 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 402 ->
+    | 408 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 401 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 403 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 175 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -390,9 +390,9 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 183 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 301 ->
+    | 302 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 299 ->
+    | 300 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 185 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
@@ -404,13 +404,13 @@ let message =
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 190 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 195 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 214 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | 194 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 213 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 193 ->
-        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
-    | 209 ->
+    | 210 ->
         "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
     | _ ->
         raise Not_found
diff --git a/src/passes/1-parser/cameligo/Parser.mly b/src/passes/1-parser/cameligo/Parser.mly
index 8863da3f1..11f858752 100644
--- a/src/passes/1-parser/cameligo/Parser.mly
+++ b/src/passes/1-parser/cameligo/Parser.mly
@@ -566,6 +566,7 @@ core_expr:
   "<int>"                             {               EArith (Int $1) }
 | "<mutez>"                           {             EArith (Mutez $1) }
 | "<nat>"                             {               EArith (Nat $1) }
+| "<bytes>"                           {                     EBytes $1 }
 | "<ident>" | module_field            {                       EVar $1 }
 | projection                          {                      EProj $1 }
 | "<string>"                          {           EString (String $1) }
diff --git a/src/passes/1-parser/cameligo/ParserAPI.ml b/src/passes/1-parser/cameligo/ParserAPI.ml
index 412ae199f..0c78cdeec 100644
--- a/src/passes/1-parser/cameligo/ParserAPI.ml
+++ b/src/passes/1-parser/cameligo/ParserAPI.ml
@@ -75,8 +75,6 @@ module Make (Lexer: Lexer.S)
 
     (* The parser has suspended itself because of a syntax error. Stop. *)
 
-    (* let fail _checkpoint = raise Parser.Error *)
-
     let failure get_win checkpoint =
       let message = ParErr.message (state checkpoint) in
       match get_win () with
diff --git a/src/passes/1-parser/reasonligo/ParErr.ml b/src/passes/1-parser/reasonligo/ParErr.ml
new file mode 100644
index 000000000..594f9ecd4
--- /dev/null
+++ b/src/passes/1-parser/reasonligo/ParErr.ml
@@ -0,0 +1,510 @@
+
+(* This file was auto-generated based on "Parser.msg". *)
+
+(* Please note that the function [message] can raise [Not_found]. *)
+
+let message =
+  fun s ->
+    match s with
+    | 0 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 1 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 2 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 3 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 4 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 5 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 55 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 6 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 52 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 54 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 7 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 38 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 8 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 9 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 32 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 36 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 35 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 10 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 31 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 11 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 509 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 503 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 48 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 12 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 19 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 20 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 43 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 46 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 49 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 13 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 14 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 60 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 65 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 505 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 145 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 146 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 144 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 329 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 331 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 330 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 61 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 64 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 59 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 143 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 338 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 340 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 339 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 151 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 152 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 78 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 325 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 327 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 326 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 92 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 155 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 118 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 125 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 87 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 105 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 107 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 108 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 106 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 88 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 93 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 80 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 81 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 82 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 132 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 334 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 336 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 335 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 133 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 136 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 137 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 157 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 159 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 158 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 512 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 218 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 514 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 216 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 250 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 248 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 249 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 230 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 235 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 252 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 254 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 255 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 258 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 219 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 226 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 227 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 260 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 262 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 264 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 266 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 194 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 195 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 206 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 215 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 199 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 207 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 208 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 196 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 197 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 198 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 256 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 257 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 277 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 233 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 279 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 67 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 463 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 464 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 387 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 121 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 122 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 120 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 466 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 467 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 483 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 492 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 469 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 470 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 468 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 471 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 472 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 473 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 475 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 476 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 477 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 478 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 487 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 488 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 474 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 499 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 497 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 465 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 321 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 315 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 316 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 318 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 317 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 314 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 71 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 410 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 298 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 304 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 305 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 308 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 309 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 300 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 178 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 73 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 75 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 419 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 420 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 77 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 160 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 412 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 413 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 415 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 416 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 193 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 229 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 74 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 447 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 448 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 456 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 457 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 459 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 460 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 449 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 450 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 76 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 440 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 441 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 425 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 422 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 428 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 429 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 434 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 438 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 437 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 433 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 423 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 427 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 162 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 163 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 290 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 295 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 296 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 357 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 400 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 401 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 402 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 403 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 404 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 405 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 399 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 297 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 311 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 312 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 322 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 323 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 377 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 384 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 342 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 343 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 324 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 344 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 345 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 346 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 370 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 371 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 372 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 373 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 379 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 380 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 369 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 393 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 391 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 313 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 348 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 349 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 347 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 350 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 351 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 352 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 359 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 360 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 361 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 362 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 364 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 363 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 358 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 292 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 293 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 164 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 165 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 166 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 167 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 168 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 169 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 174 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 175 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 176 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 188 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | 237 ->
+        "<YOUR SYNTAX ERROR MESSAGE HERE>\n"
+    | _ ->
+        raise Not_found
diff --git a/src/passes/1-parser/reasonligo/Parser.mly b/src/passes/1-parser/reasonligo/Parser.mly
index 23deaf776..2026605ac 100644
--- a/src/passes/1-parser/reasonligo/Parser.mly
+++ b/src/passes/1-parser/reasonligo/Parser.mly
@@ -320,6 +320,8 @@ core_pattern:
 | "_"                                                    {   PWild $1 }
 | unit                                                   {   PUnit $1 }
 | "<int>"                                                {    PInt $1 }
+| "<nat>"                                                {    PNat $1 }
+| "<bytes>"                                              {  PBytes $1 }
 | "true"                                                 {   PTrue $1 }
 | "false"                                                {  PFalse $1 }
 | "<string>"                                             { PString $1 }
@@ -424,7 +426,8 @@ fun_expr:
           {p.value with inside = arg_to_pattern p.value.inside}
         in PPar {p with value}
     | EUnit u -> PUnit u
-    | e -> raise (SyntaxError.Error (WrongFunctionArguments e))
+    | e -> let open! SyntaxError
+          in raise (Error (WrongFunctionArguments e))
     in
     let fun_args_to_pattern = function
       EAnnot {
@@ -453,7 +456,8 @@ fun_expr:
           in arg_to_pattern (fst fun_args), bindings
       | EUnit e ->
           arg_to_pattern (EUnit e), []
-      | e -> raise (SyntaxError.Error (WrongFunctionArguments e))
+      | e -> let open! SyntaxError
+            in raise (Error (WrongFunctionArguments e))
     in
     let binders = fun_args_to_pattern $1 in
     let f = {kwd_fun;
@@ -682,6 +686,7 @@ common_expr:
   "<int>"                             {               EArith (Int $1) }
 | "<mutez>"                           {             EArith (Mutez $1) }
 | "<nat>"                             {               EArith (Nat $1) }
+| "<bytes>"                           {                     EBytes $1 }
 | "<ident>" | module_field            {                       EVar $1 }
 | projection                          {                      EProj $1 }
 | "<string>"                          {           EString (String $1) }
diff --git a/src/passes/1-parser/reasonligo/ParserAPI.ml b/src/passes/1-parser/reasonligo/ParserAPI.ml
index 7ae5c5ad4..0c78cdeec 100644
--- a/src/passes/1-parser/reasonligo/ParserAPI.ml
+++ b/src/passes/1-parser/reasonligo/ParserAPI.ml
@@ -28,13 +28,46 @@ module type PARSER =
       end
   end
 
+(* Errors *)
+
+module type PAR_ERR =
+  sig
+    val message : int -> string   (* From error states to messages *)
+  end
+
+let format_error ?(offsets=true) mode Region.{region; value} ~file =
+  let reg = region#to_string ~file ~offsets mode in
+  Printf.sprintf "\027[31mParse error %s:\n%s\027[0m%!" reg value
+
 (* Main functor *)
 
 module Make (Lexer: Lexer.S)
-            (Parser: PARSER with type token = Lexer.Token.token) =
+            (Parser: PARSER with type token = Lexer.Token.token)
+            (ParErr: PAR_ERR) =
   struct
+    type message = string
+    type valid   = Lexer.token
+    type invalid = Lexer.token
+
+    exception Point of message * valid option * invalid
 
     module I = Parser.MenhirInterpreter
+    module S = MenhirLib.General (* Streams *)
+
+    (* The call [stack checkpoint] extracts the parser's stack out of
+       a checkpoint. *)
+
+    let stack = function
+      I.HandlingError env -> I.stack env
+    |                   _ -> assert false
+
+    (* The call [state checkpoint] extracts the number of the current
+       state out of a parser checkpoint. *)
+
+    let state checkpoint : int =
+      match Lazy.force (stack checkpoint) with
+        S.Nil -> 0 (* WARNING: Hack. The first state should be 0. *)
+      | S.Cons (I.Element (s,_,_,_),_) -> I.number s
 
     (* The parser has successfully produced a semantic value. *)
 
@@ -42,14 +75,22 @@ module Make (Lexer: Lexer.S)
 
     (* The parser has suspended itself because of a syntax error. Stop. *)
 
-    let fail _checkpoint = raise Parser.Error
+    let failure get_win checkpoint =
+      let message = ParErr.message (state checkpoint) in
+      match get_win () with
+        Lexer.Nil -> assert false
+      | Lexer.One invalid ->
+          raise (Point (message, None, invalid))
+      | Lexer.Two (invalid, valid) ->
+          raise (Point (message, Some valid, invalid))
 
     (* The generic parsing function *)
 
-    let incr_contract Lexer.{read; buffer; close; _} : AST.t =
-      let supplier = I.lexer_lexbuf_to_supplier read buffer in
-      let parser = Parser.Incremental.contract buffer.Lexing.lex_curr_p in
-      let ast = I.loop_handle success fail supplier parser
+    let incr_contract Lexer.{read; buffer; get_win; close; _} : AST.t =
+      let supplier = I.lexer_lexbuf_to_supplier read buffer
+      and failure  = failure get_win in
+      let parser   = Parser.Incremental.contract buffer.Lexing.lex_curr_p in
+      let ast = I.loop_handle success failure supplier parser
       in close (); ast
 
     let mono_contract = Parser.contract
diff --git a/src/passes/1-parser/reasonligo/ParserAPI.mli b/src/passes/1-parser/reasonligo/ParserAPI.mli
index ff3fe4854..f3eeaaba8 100644
--- a/src/passes/1-parser/reasonligo/ParserAPI.mli
+++ b/src/passes/1-parser/reasonligo/ParserAPI.mli
@@ -29,11 +29,29 @@ module type PARSER =
 
   end
 
+(* Errors *)
+
+module type PAR_ERR =
+  sig
+    val message : int -> string   (* From error states to messages *)
+  end
+
+val format_error :
+  ?offsets:bool -> [`Byte | `Point] ->
+  string Region.reg -> file:bool -> string
+
 (* Main functor *)
 
 module Make (Lexer: Lexer.S)
-            (Parser: PARSER with type token = Lexer.Token.token) :
+            (Parser: PARSER with type token = Lexer.Token.token)
+            (ParErr: PAR_ERR) :
   sig
+    type message = string
+    type valid   = Lexer.token
+    type invalid = Lexer.token
+
+    exception Point of message * valid option * invalid
+
     val mono_contract : (Lexing.lexbuf -> Lexer.token) -> Lexing.lexbuf -> AST.t
     val incr_contract : Lexer.instance -> AST.t
   end