diff --git a/lib/lrama/parser.rb b/lib/lrama/parser.rb
index e163f748..b7171454 100644
--- a/lib/lrama/parser.rb
+++ b/lib/lrama/parser.rb
@@ -654,7 +654,7 @@ def token_to_str(t)
 module Lrama
   class Parser < Racc::Parser
 
-module_eval(<<'...end parser.y/module_eval...', 'parser.y', 541)
+module_eval(<<'...end parser.y/module_eval...', 'parser.y', 542)
 
 include Lrama::Report::Duration
 
@@ -1261,7 +1261,7 @@ def raise_parse_error(error_message, location)
 
 # reduce 3 omitted
 
-module_eval(<<'.,.,', 'parser.y', 14)
+module_eval(<<'.,.,', 'parser.y', 15)
   def _reduce_4(val, _values, result)
                                 begin_c_declaration("%}")
                             @grammar.prologue_first_lineno = @lexer.line
@@ -1270,7 +1270,7 @@ def _reduce_4(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 19)
+module_eval(<<'.,.,', 'parser.y', 20)
   def _reduce_5(val, _values, result)
                                 end_c_declaration
 
@@ -1278,7 +1278,7 @@ def _reduce_5(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 23)
+module_eval(<<'.,.,', 'parser.y', 24)
   def _reduce_6(val, _values, result)
                                 @grammar.prologue = val[2].s_value
 
@@ -1288,7 +1288,7 @@ def _reduce_6(val, _values, result)
 
 # reduce 7 omitted
 
-module_eval(<<'.,.,', 'parser.y', 27)
+module_eval(<<'.,.,', 'parser.y', 28)
   def _reduce_8(val, _values, result)
      result = ""
     result
@@ -1303,7 +1303,7 @@ def _reduce_8(val, _values, result)
 
 # reduce 12 omitted
 
-module_eval(<<'.,.,', 'parser.y', 33)
+module_eval(<<'.,.,', 'parser.y', 34)
   def _reduce_13(val, _values, result)
      @grammar.expect = val[1]
     result
@@ -1314,7 +1314,7 @@ def _reduce_13(val, _values, result)
 
 # reduce 15 omitted
 
-module_eval(<<'.,.,', 'parser.y', 38)
+module_eval(<<'.,.,', 'parser.y', 39)
   def _reduce_16(val, _values, result)
                              val[1].each {|token|
                            @grammar.lex_param = Grammar::Code::NoReferenceCode.new(type: :lex_param, token_code: token).token_code.s_value
@@ -1324,7 +1324,7 @@ def _reduce_16(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 44)
+module_eval(<<'.,.,', 'parser.y', 45)
   def _reduce_17(val, _values, result)
                              val[1].each {|token|
                            @grammar.parse_param = Grammar::Code::NoReferenceCode.new(type: :parse_param, token_code: token).token_code.s_value
@@ -1334,7 +1334,7 @@ def _reduce_17(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 50)
+module_eval(<<'.,.,', 'parser.y', 51)
   def _reduce_18(val, _values, result)
                              begin_c_declaration("}")
 
@@ -1342,7 +1342,7 @@ def _reduce_18(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 54)
+module_eval(<<'.,.,', 'parser.y', 55)
   def _reduce_19(val, _values, result)
                              end_c_declaration
 
@@ -1350,7 +1350,7 @@ def _reduce_19(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 58)
+module_eval(<<'.,.,', 'parser.y', 59)
   def _reduce_20(val, _values, result)
                              @grammar.add_percent_code(id: val[1], code: val[4])
 
@@ -1358,7 +1358,7 @@ def _reduce_20(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 62)
+module_eval(<<'.,.,', 'parser.y', 63)
   def _reduce_21(val, _values, result)
                              begin_c_declaration("}")
 
@@ -1366,7 +1366,7 @@ def _reduce_21(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 66)
+module_eval(<<'.,.,', 'parser.y', 67)
   def _reduce_22(val, _values, result)
                              end_c_declaration
 
@@ -1374,7 +1374,7 @@ def _reduce_22(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 70)
+module_eval(<<'.,.,', 'parser.y', 71)
   def _reduce_23(val, _values, result)
                              @grammar.initial_action = Grammar::Code::InitialActionCode.new(type: :initial_action, token_code: val[3])
 
@@ -1382,7 +1382,7 @@ def _reduce_23(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 72)
+module_eval(<<'.,.,', 'parser.y', 73)
   def _reduce_24(val, _values, result)
      @grammar.no_stdlib = true
     result
@@ -1391,7 +1391,7 @@ def _reduce_24(val, _values, result)
 
 # reduce 25 omitted
 
-module_eval(<<'.,.,', 'parser.y', 77)
+module_eval(<<'.,.,', 'parser.y', 78)
   def _reduce_26(val, _values, result)
                                begin_c_declaration("}")
 
@@ -1399,7 +1399,7 @@ def _reduce_26(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 81)
+module_eval(<<'.,.,', 'parser.y', 82)
   def _reduce_27(val, _values, result)
                                end_c_declaration
 
@@ -1407,7 +1407,7 @@ def _reduce_27(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 85)
+module_eval(<<'.,.,', 'parser.y', 86)
   def _reduce_28(val, _values, result)
                                @grammar.set_union(
                              Grammar::Code::NoReferenceCode.new(type: :union, token_code: val[3]),
@@ -1420,7 +1420,7 @@ def _reduce_28(val, _values, result)
 
 # reduce 29 omitted
 
-module_eval(<<'.,.,', 'parser.y', 93)
+module_eval(<<'.,.,', 'parser.y', 94)
   def _reduce_30(val, _values, result)
                                begin_c_declaration("}")
 
@@ -1428,7 +1428,7 @@ def _reduce_30(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 97)
+module_eval(<<'.,.,', 'parser.y', 98)
   def _reduce_31(val, _values, result)
                                end_c_declaration
 
@@ -1436,7 +1436,7 @@ def _reduce_31(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 101)
+module_eval(<<'.,.,', 'parser.y', 102)
   def _reduce_32(val, _values, result)
                                @grammar.add_destructor(
                              ident_or_tags: val[6],
@@ -1448,7 +1448,7 @@ def _reduce_32(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 109)
+module_eval(<<'.,.,', 'parser.y', 110)
   def _reduce_33(val, _values, result)
                                begin_c_declaration("}")
 
@@ -1456,7 +1456,7 @@ def _reduce_33(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 113)
+module_eval(<<'.,.,', 'parser.y', 114)
   def _reduce_34(val, _values, result)
                                end_c_declaration
 
@@ -1464,7 +1464,7 @@ def _reduce_34(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 117)
+module_eval(<<'.,.,', 'parser.y', 118)
   def _reduce_35(val, _values, result)
                                @grammar.add_printer(
                              ident_or_tags: val[6],
@@ -1476,7 +1476,7 @@ def _reduce_35(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 125)
+module_eval(<<'.,.,', 'parser.y', 126)
   def _reduce_36(val, _values, result)
                                begin_c_declaration("}")
 
@@ -1484,7 +1484,7 @@ def _reduce_36(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 129)
+module_eval(<<'.,.,', 'parser.y', 130)
   def _reduce_37(val, _values, result)
                                end_c_declaration
 
@@ -1492,7 +1492,7 @@ def _reduce_37(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 133)
+module_eval(<<'.,.,', 'parser.y', 134)
   def _reduce_38(val, _values, result)
                                @grammar.add_error_token(
                              ident_or_tags: val[6],
@@ -1504,7 +1504,7 @@ def _reduce_38(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 141)
+module_eval(<<'.,.,', 'parser.y', 142)
   def _reduce_39(val, _values, result)
                                @grammar.after_shift = val[1]
 
@@ -1512,7 +1512,7 @@ def _reduce_39(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 145)
+module_eval(<<'.,.,', 'parser.y', 146)
   def _reduce_40(val, _values, result)
                                @grammar.before_reduce = val[1]
 
@@ -1520,7 +1520,7 @@ def _reduce_40(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 149)
+module_eval(<<'.,.,', 'parser.y', 150)
   def _reduce_41(val, _values, result)
                                @grammar.after_reduce = val[1]
 
@@ -1528,7 +1528,7 @@ def _reduce_41(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 153)
+module_eval(<<'.,.,', 'parser.y', 154)
   def _reduce_42(val, _values, result)
                                @grammar.after_shift_error_token = val[1]
 
@@ -1536,7 +1536,7 @@ def _reduce_42(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 157)
+module_eval(<<'.,.,', 'parser.y', 158)
   def _reduce_43(val, _values, result)
                                @grammar.after_pop_stack = val[1]
 
@@ -1546,7 +1546,7 @@ def _reduce_43(val, _values, result)
 
 # reduce 44 omitted
 
-module_eval(<<'.,.,', 'parser.y', 163)
+module_eval(<<'.,.,', 'parser.y', 164)
   def _reduce_45(val, _values, result)
                               val[1].each {|hash|
                             hash[:tokens].each {|id|
@@ -1558,7 +1558,7 @@ def _reduce_45(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 171)
+module_eval(<<'.,.,', 'parser.y', 172)
   def _reduce_46(val, _values, result)
                               val[1].each {|hash|
                             hash[:tokens].each {|id|
@@ -1572,7 +1572,7 @@ def _reduce_46(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 181)
+module_eval(<<'.,.,', 'parser.y', 182)
   def _reduce_47(val, _values, result)
                               val[1].each {|hash|
                             hash[:tokens].each {|id|
@@ -1586,7 +1586,7 @@ def _reduce_47(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 191)
+module_eval(<<'.,.,', 'parser.y', 192)
   def _reduce_48(val, _values, result)
                               val[1].each {|hash|
                             hash[:tokens].each {|id|
@@ -1600,7 +1600,7 @@ def _reduce_48(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 201)
+module_eval(<<'.,.,', 'parser.y', 202)
   def _reduce_49(val, _values, result)
                               val[1].each {|hash|
                             hash[:tokens].each {|id|
@@ -1614,7 +1614,7 @@ def _reduce_49(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 212)
+module_eval(<<'.,.,', 'parser.y', 213)
   def _reduce_50(val, _values, result)
                               val[0].each {|token_declaration|
                             @grammar.add_term(id: token_declaration[0], alias_name: token_declaration[2], token_id: token_declaration[1], tag: nil, replace: true)
@@ -1624,7 +1624,7 @@ def _reduce_50(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 218)
+module_eval(<<'.,.,', 'parser.y', 219)
   def _reduce_51(val, _values, result)
                               val[1].each {|token_declaration|
                             @grammar.add_term(id: token_declaration[0], alias_name: token_declaration[2], token_id: token_declaration[1], tag: val[0], replace: true)
@@ -1634,7 +1634,7 @@ def _reduce_51(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 224)
+module_eval(<<'.,.,', 'parser.y', 225)
   def _reduce_52(val, _values, result)
                               val[2].each {|token_declaration|
                             @grammar.add_term(id: token_declaration[0], alias_name: token_declaration[2], token_id: token_declaration[1], tag: val[1], replace: true)
@@ -1644,28 +1644,28 @@ def _reduce_52(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 229)
+module_eval(<<'.,.,', 'parser.y', 230)
   def _reduce_53(val, _values, result)
      result = [val[0]]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 230)
+module_eval(<<'.,.,', 'parser.y', 231)
   def _reduce_54(val, _values, result)
      result = val[0].append(val[1])
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 232)
+module_eval(<<'.,.,', 'parser.y', 233)
   def _reduce_55(val, _values, result)
      result = val
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 236)
+module_eval(<<'.,.,', 'parser.y', 237)
   def _reduce_56(val, _values, result)
                             rule = Grammar::ParameterizingRule::Rule.new(val[1].s_value, val[3], val[7], tag: val[5])
                         @grammar.add_parameterizing_rule(rule)
@@ -1674,7 +1674,7 @@ def _reduce_56(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 242)
+module_eval(<<'.,.,', 'parser.y', 243)
   def _reduce_57(val, _values, result)
                             rule = Grammar::ParameterizingRule::Rule.new(val[2].s_value, [], val[4], is_inline: true)
                         @grammar.add_parameterizing_rule(rule)
@@ -1683,7 +1683,7 @@ def _reduce_57(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 247)
+module_eval(<<'.,.,', 'parser.y', 248)
   def _reduce_58(val, _values, result)
                             rule = Grammar::ParameterizingRule::Rule.new(val[2].s_value, val[4], val[7], is_inline: true)
                         @grammar.add_parameterizing_rule(rule)
@@ -1692,21 +1692,21 @@ def _reduce_58(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 251)
+module_eval(<<'.,.,', 'parser.y', 252)
   def _reduce_59(val, _values, result)
      result = [val[0]]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 252)
+module_eval(<<'.,.,', 'parser.y', 253)
   def _reduce_60(val, _values, result)
      result = val[0].append(val[2])
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 256)
+module_eval(<<'.,.,', 'parser.y', 257)
   def _reduce_61(val, _values, result)
                       builder = val[0]
                   result = [builder]
@@ -1715,7 +1715,7 @@ def _reduce_61(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 261)
+module_eval(<<'.,.,', 'parser.y', 262)
   def _reduce_62(val, _values, result)
                       builder = val[2]
                   result = val[0].append(builder)
@@ -1724,7 +1724,7 @@ def _reduce_62(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 267)
+module_eval(<<'.,.,', 'parser.y', 268)
   def _reduce_63(val, _values, result)
                   reset_precs
               result = Grammar::ParameterizingRule::Rhs.new
@@ -1733,7 +1733,7 @@ def _reduce_63(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 272)
+module_eval(<<'.,.,', 'parser.y', 273)
   def _reduce_64(val, _values, result)
                   reset_precs
               result = Grammar::ParameterizingRule::Rhs.new
@@ -1742,7 +1742,7 @@ def _reduce_64(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 277)
+module_eval(<<'.,.,', 'parser.y', 278)
   def _reduce_65(val, _values, result)
                   token = val[1]
               token.alias_name = val[2]
@@ -1754,7 +1754,7 @@ def _reduce_65(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 285)
+module_eval(<<'.,.,', 'parser.y', 286)
   def _reduce_66(val, _values, result)
                     builder = val[0]
                 builder.symbols << Lrama::Lexer::Token::InstantiateRule.new(s_value: val[2], location: @lexer.location, args: [val[1]])
@@ -1764,7 +1764,7 @@ def _reduce_66(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 291)
+module_eval(<<'.,.,', 'parser.y', 292)
   def _reduce_67(val, _values, result)
                     builder = val[0]
                 builder.symbols << Lrama::Lexer::Token::InstantiateRule.new(s_value: val[1].s_value, location: @lexer.location, args: val[3], lhs_tag: val[5])
@@ -1774,7 +1774,7 @@ def _reduce_67(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 297)
+module_eval(<<'.,.,', 'parser.y', 298)
   def _reduce_68(val, _values, result)
                   if @prec_seen
                 on_action_error("multiple User_code after %prec", val[0])  if @code_after_prec
@@ -1786,7 +1786,7 @@ def _reduce_68(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 305)
+module_eval(<<'.,.,', 'parser.y', 306)
   def _reduce_69(val, _values, result)
                   end_c_declaration
 
@@ -1794,7 +1794,7 @@ def _reduce_69(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 309)
+module_eval(<<'.,.,', 'parser.y', 310)
   def _reduce_70(val, _values, result)
                   user_code = val[3]
               user_code.alias_name = val[6]
@@ -1806,7 +1806,7 @@ def _reduce_70(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 317)
+module_eval(<<'.,.,', 'parser.y', 318)
   def _reduce_71(val, _values, result)
                   sym = @grammar.find_symbol_by_id!(val[2])
               @prec_seen = true
@@ -1826,7 +1826,7 @@ def _reduce_71(val, _values, result)
 
 # reduce 75 omitted
 
-module_eval(<<'.,.,', 'parser.y', 332)
+module_eval(<<'.,.,', 'parser.y', 333)
   def _reduce_76(val, _values, result)
                                result = [{tag: nil, tokens: val[0]}]
 
@@ -1834,7 +1834,7 @@ def _reduce_76(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 336)
+module_eval(<<'.,.,', 'parser.y', 337)
   def _reduce_77(val, _values, result)
                                result = [{tag: val[0], tokens: val[1]}]
 
@@ -1842,7 +1842,7 @@ def _reduce_77(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 340)
+module_eval(<<'.,.,', 'parser.y', 341)
   def _reduce_78(val, _values, result)
                              result = val[0].append({tag: val[1], tokens: val[2]})
 
@@ -1850,14 +1850,14 @@ def _reduce_78(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 343)
+module_eval(<<'.,.,', 'parser.y', 344)
   def _reduce_79(val, _values, result)
      result = [val[0]]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 344)
+module_eval(<<'.,.,', 'parser.y', 345)
   def _reduce_80(val, _values, result)
      result = val[0].append(val[1])
     result
@@ -1868,7 +1868,7 @@ def _reduce_80(val, _values, result)
 
 # reduce 82 omitted
 
-module_eval(<<'.,.,', 'parser.y', 351)
+module_eval(<<'.,.,', 'parser.y', 352)
   def _reduce_83(val, _values, result)
                   begin_c_declaration("}")
 
@@ -1876,7 +1876,7 @@ def _reduce_83(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 355)
+module_eval(<<'.,.,', 'parser.y', 356)
   def _reduce_84(val, _values, result)
                   end_c_declaration
 
@@ -1884,7 +1884,7 @@ def _reduce_84(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 359)
+module_eval(<<'.,.,', 'parser.y', 360)
   def _reduce_85(val, _values, result)
                   result = val[0].append(val[3])
 
@@ -1892,7 +1892,7 @@ def _reduce_85(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 363)
+module_eval(<<'.,.,', 'parser.y', 364)
   def _reduce_86(val, _values, result)
                   begin_c_declaration("}")
 
@@ -1900,7 +1900,7 @@ def _reduce_86(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 367)
+module_eval(<<'.,.,', 'parser.y', 368)
   def _reduce_87(val, _values, result)
                   end_c_declaration
 
@@ -1908,7 +1908,7 @@ def _reduce_87(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 371)
+module_eval(<<'.,.,', 'parser.y', 372)
   def _reduce_88(val, _values, result)
                   result = [val[2]]
 
@@ -1916,7 +1916,7 @@ def _reduce_88(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 376)
+module_eval(<<'.,.,', 'parser.y', 377)
   def _reduce_89(val, _values, result)
                                              result = [{tag: nil, tokens: val[0]}]
 
@@ -1924,7 +1924,7 @@ def _reduce_89(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 380)
+module_eval(<<'.,.,', 'parser.y', 381)
   def _reduce_90(val, _values, result)
                                              result = [{tag: val[0], tokens: val[1]}]
 
@@ -1932,7 +1932,7 @@ def _reduce_90(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 384)
+module_eval(<<'.,.,', 'parser.y', 385)
   def _reduce_91(val, _values, result)
                                              result = val[0].append({tag: val[1], tokens: val[2]})
 
@@ -1940,14 +1940,14 @@ def _reduce_91(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 387)
+module_eval(<<'.,.,', 'parser.y', 388)
   def _reduce_92(val, _values, result)
      result = [val[0]]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 388)
+module_eval(<<'.,.,', 'parser.y', 389)
   def _reduce_93(val, _values, result)
      result = val[0].append(val[1])
     result
@@ -1956,14 +1956,14 @@ def _reduce_93(val, _values, result)
 
 # reduce 94 omitted
 
-module_eval(<<'.,.,', 'parser.y', 392)
+module_eval(<<'.,.,', 'parser.y', 393)
   def _reduce_95(val, _values, result)
      on_action_error("ident after %prec", val[0]) if @prec_seen
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 393)
+module_eval(<<'.,.,', 'parser.y', 394)
   def _reduce_96(val, _values, result)
      on_action_error("char after %prec", val[0]) if @prec_seen
     result
@@ -1978,7 +1978,7 @@ def _reduce_96(val, _values, result)
 
 # reduce 100 omitted
 
-module_eval(<<'.,.,', 'parser.y', 403)
+module_eval(<<'.,.,', 'parser.y', 404)
   def _reduce_101(val, _values, result)
                  lhs = val[0]
              lhs.alias_name = val[1]
@@ -1992,7 +1992,7 @@ def _reduce_101(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 414)
+module_eval(<<'.,.,', 'parser.y', 415)
   def _reduce_102(val, _values, result)
                     builder = val[0]
                 if !builder.line
@@ -2004,7 +2004,7 @@ def _reduce_102(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 422)
+module_eval(<<'.,.,', 'parser.y', 423)
   def _reduce_103(val, _values, result)
                     builder = val[2]
                 if !builder.line
@@ -2018,7 +2018,7 @@ def _reduce_103(val, _values, result)
 
 # reduce 104 omitted
 
-module_eval(<<'.,.,', 'parser.y', 432)
+module_eval(<<'.,.,', 'parser.y', 433)
   def _reduce_105(val, _values, result)
                reset_precs
            result = @grammar.create_rule_builder(@rule_counter, @midrule_action_counter)
@@ -2027,7 +2027,7 @@ def _reduce_105(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 437)
+module_eval(<<'.,.,', 'parser.y', 438)
   def _reduce_106(val, _values, result)
                reset_precs
            result = @grammar.create_rule_builder(@rule_counter, @midrule_action_counter)
@@ -2036,7 +2036,7 @@ def _reduce_106(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 442)
+module_eval(<<'.,.,', 'parser.y', 443)
   def _reduce_107(val, _values, result)
                token = val[1]
            token.alias_name = val[2]
@@ -2048,7 +2048,7 @@ def _reduce_107(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 450)
+module_eval(<<'.,.,', 'parser.y', 451)
   def _reduce_108(val, _values, result)
                token = Lrama::Lexer::Token::InstantiateRule.new(s_value: val[2], location: @lexer.location, args: [val[1]], lhs_tag: val[3])
            builder = val[0]
@@ -2060,7 +2060,7 @@ def _reduce_108(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 458)
+module_eval(<<'.,.,', 'parser.y', 459)
   def _reduce_109(val, _values, result)
                token = Lrama::Lexer::Token::InstantiateRule.new(s_value: val[1].s_value, location: @lexer.location, args: val[3], lhs_tag: val[5])
            builder = val[0]
@@ -2072,7 +2072,7 @@ def _reduce_109(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 466)
+module_eval(<<'.,.,', 'parser.y', 467)
   def _reduce_110(val, _values, result)
                if @prec_seen
              on_action_error("multiple User_code after %prec", val[0])  if @code_after_prec
@@ -2084,7 +2084,7 @@ def _reduce_110(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 474)
+module_eval(<<'.,.,', 'parser.y', 475)
   def _reduce_111(val, _values, result)
                end_c_declaration
 
@@ -2092,7 +2092,7 @@ def _reduce_111(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 478)
+module_eval(<<'.,.,', 'parser.y', 479)
   def _reduce_112(val, _values, result)
                user_code = val[3]
            user_code.alias_name = val[6]
@@ -2105,7 +2105,7 @@ def _reduce_112(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 487)
+module_eval(<<'.,.,', 'parser.y', 488)
   def _reduce_113(val, _values, result)
                sym = @grammar.find_symbol_by_id!(val[2])
            @prec_seen = true
@@ -2117,49 +2117,49 @@ def _reduce_113(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 494)
+module_eval(<<'.,.,', 'parser.y', 495)
   def _reduce_114(val, _values, result)
      result = "option"
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 495)
+module_eval(<<'.,.,', 'parser.y', 496)
   def _reduce_115(val, _values, result)
      result = "nonempty_list"
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 496)
+module_eval(<<'.,.,', 'parser.y', 497)
   def _reduce_116(val, _values, result)
      result = "list"
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 498)
+module_eval(<<'.,.,', 'parser.y', 499)
   def _reduce_117(val, _values, result)
      result = [val[0]]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 499)
+module_eval(<<'.,.,', 'parser.y', 500)
   def _reduce_118(val, _values, result)
      result = val[0].append(val[2])
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 500)
+module_eval(<<'.,.,', 'parser.y', 501)
   def _reduce_119(val, _values, result)
      result = [Lrama::Lexer::Token::InstantiateRule.new(s_value: val[1].s_value, location: @lexer.location, args: val[0])]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 501)
+module_eval(<<'.,.,', 'parser.y', 502)
   def _reduce_120(val, _values, result)
      result = [Lrama::Lexer::Token::InstantiateRule.new(s_value: val[0].s_value, location: @lexer.location, args: val[2])]
     result
@@ -2168,7 +2168,7 @@ def _reduce_120(val, _values, result)
 
 # reduce 121 omitted
 
-module_eval(<<'.,.,', 'parser.y', 504)
+module_eval(<<'.,.,', 'parser.y', 505)
   def _reduce_122(val, _values, result)
      result = val[1].s_value
     result
@@ -2179,7 +2179,7 @@ def _reduce_122(val, _values, result)
 
 # reduce 124 omitted
 
-module_eval(<<'.,.,', 'parser.y', 511)
+module_eval(<<'.,.,', 'parser.y', 512)
   def _reduce_125(val, _values, result)
                         begin_c_declaration('\Z')
                     @grammar.epilogue_first_lineno = @lexer.line + 1
@@ -2188,7 +2188,7 @@ def _reduce_125(val, _values, result)
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 516)
+module_eval(<<'.,.,', 'parser.y', 517)
   def _reduce_126(val, _values, result)
                         end_c_declaration
                     @grammar.epilogue = val[2].s_value
@@ -2207,14 +2207,14 @@ def _reduce_126(val, _values, result)
 
 # reduce 131 omitted
 
-module_eval(<<'.,.,', 'parser.y', 527)
+module_eval(<<'.,.,', 'parser.y', 528)
   def _reduce_132(val, _values, result)
      result = [val[0]]
     result
   end
 .,.,
 
-module_eval(<<'.,.,', 'parser.y', 528)
+module_eval(<<'.,.,', 'parser.y', 529)
   def _reduce_133(val, _values, result)
      result = val[0].append(val[1])
     result
@@ -2225,7 +2225,7 @@ def _reduce_133(val, _values, result)
 
 # reduce 135 omitted
 
-module_eval(<<'.,.,', 'parser.y', 533)
+module_eval(<<'.,.,', 'parser.y', 534)
   def _reduce_136(val, _values, result)
      result = Lrama::Lexer::Token::Ident.new(s_value: val[0])
     result
diff --git a/parser.y b/parser.y
index 893a7add..fc9d8f24 100644
--- a/parser.y
+++ b/parser.y
@@ -1,5 +1,6 @@
 class Lrama::Parser
   expect 0
+  error_on_expect_mismatch
 
   token C_DECLARATION CHARACTER IDENT_COLON IDENTIFIER INTEGER STRING TAG