parser: improve error messages

[Fix GH-2011]

From: Akim Demaille <akim.demaille@gmail.com>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65969 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

parse.y

@@ -776,55 +776,55 @@ static void token_info_warn(struct parser_params *p, const char *token, token_in
 }
 
 %token <id>
-	keyword_class
-	keyword_module
-	keyword_def
-	keyword_undef
-	keyword_begin
-	keyword_rescue
-	keyword_ensure
-	keyword_end
-	keyword_if
-	keyword_unless
-	keyword_then
-	keyword_elsif
-	keyword_else
-	keyword_case
-	keyword_when
-	keyword_while
-	keyword_until
-	keyword_for
-	keyword_break
-	keyword_next
-	keyword_redo
-	keyword_retry
-	keyword_in
-	keyword_do
-	keyword_do_cond
-	keyword_do_block
-	keyword_do_LAMBDA
-	keyword_return
-	keyword_yield
-	keyword_super
-	keyword_self
-	keyword_nil
-	keyword_true
-	keyword_false
-	keyword_and
-	keyword_or
-	keyword_not
-	modifier_if
-	modifier_unless
-	modifier_while
-	modifier_until
-	modifier_rescue
-	keyword_alias
-	keyword_defined
-	keyword_BEGIN
-	keyword_END
-	keyword__LINE__
-	keyword__FILE__
-	keyword__ENCODING__
+        keyword_class        "class"
+        keyword_module       "module"
+        keyword_def          "def"
+        keyword_undef        "undef"
+        keyword_begin        "begin"
+        keyword_rescue       "rescue"
+        keyword_ensure       "ensure"
+        keyword_end          "end"
+        keyword_if           "if"
+        keyword_unless       "unless"
+        keyword_then         "then"
+        keyword_elsif        "elsif"
+        keyword_else         "else"
+        keyword_case         "case"
+        keyword_when         "when"
+        keyword_while        "while"
+        keyword_until        "until"
+        keyword_for          "for"
+        keyword_break        "break"
+        keyword_next         "next"
+        keyword_redo         "redo"
+        keyword_retry        "retry"
+        keyword_in           "in"
+        keyword_do           "do"
+        keyword_do_cond      "do (for condition)"
+        keyword_do_block     "do (for block)"
+        keyword_do_LAMBDA    "do (for lambda)"
+        keyword_return       "return"
+        keyword_yield        "yield"
+        keyword_super        "super"
+        keyword_self         "self"
+        keyword_nil          "nil"
+        keyword_true         "true"
+        keyword_false        "false"
+        keyword_and          "and"
+        keyword_or           "or"
+        keyword_not          "not"
+        modifier_if          "if (modifier)"
+        modifier_unless      "unless (modifier)"
+        modifier_while       "while (modifier)"
+        modifier_until       "until (modifier)"
+        modifier_rescue      "rescue (modifier)"
+        keyword_alias        "alias"
+        keyword_defined      "defined?"
+        keyword_BEGIN        "BEGIN"
+        keyword_END          "END"
+        keyword__LINE__      "__LINE__"
+        keyword__FILE__      "__FILE__"
+        keyword__ENCODING__  "__ENCODING__"
 
 %token <id>   tIDENTIFIER tFID tGVAR tIVAR tCONSTANT tCVAR tLABEL
 %token <node> tINTEGER tFLOAT tRATIONAL tIMAGINARY tSTRING_CONTENT tCHAR

test/ruby/test_ast.rb

@@ -155,7 +155,7 @@ class TestAst < Test::Unit::TestCase
   end
 
   def test_parse_raises_syntax_error
-    assert_raise_with_message(SyntaxError, /keyword_end/) do
+    assert_raise_with_message(SyntaxError, /\bend\b/) do
       RubyVM::AbstractSyntaxTree.parse("end")
     end
   end
@@ -164,7 +164,7 @@ class TestAst < Test::Unit::TestCase
     Tempfile.create(%w"test_ast .rb") do |f|
       f.puts "end"
       f.close
-      assert_raise_with_message(SyntaxError, /keyword_end/) do
+      assert_raise_with_message(SyntaxError, /\bend\b/) do
         RubyVM::AbstractSyntaxTree.parse_file(f.path)
       end
     end

test/ruby/test_iseq.rb

@@ -256,7 +256,7 @@ class TestISeq < Test::Unit::TestCase
       f.puts "end"
       f.close
       path = f.path
-      assert_in_out_err(%W[- #{path}], "#{<<-"begin;"}\n#{<<-"end;"}", /keyword_end/, [], success: true)
+      assert_in_out_err(%W[- #{path}], "#{<<-"begin;"}\n#{<<-"end;"}", /unexpected end/, [], success: true)
       begin;
         path = ARGV[0]
         begin

test/ruby/test_syntax.rb

@@ -989,7 +989,7 @@ eom
   end
 
   def test_parenthesised_statement_argument
-    assert_syntax_error("foo(bar rescue nil)", /unexpected modifier_rescue/)
+    assert_syntax_error("foo(bar rescue nil)", /unexpected rescue \(modifier\)/)
     assert_valid_syntax("foo (bar rescue nil)")
   end