Fix creation of symbol token

Symbol tokens are created form TkIDENTIFIER with ":",
but there are several other cases.
Subclasses of TkId can become symbol token with ":",
for example reserved keywords can become symbol, "{ undef: undef }".
This commit fixes it.

Author: aycabta

lib/rdoc/ruby_lex.rb

@@ -1046,12 +1046,7 @@ def identify_identifier
                   @indent_stack.push token_c
                 end
               else
-                if peek(0) == ':' and !peek_match?(/^::/)
-                  token.concat getc
-                  token_c = TkSYMBOL
-                else
-                  token_c = TkIDENTIFIER
-                end
+                token_c = TkIDENTIFIER
               end
 
             elsif DEINDENT_CLAUSE.include?(token)
@@ -1063,6 +1058,10 @@ def identify_identifier
             @lex_state = :EXPR_END
           end
         end
+        if token_c.ancestors.include?(TkId) and peek(0) == ':' and !peek_match?(/^::/)
+          token.concat getc
+          token_c = TkSYMBOL
+        end
         return Token(token_c, token)
       end
     end
@@ -1081,19 +1080,20 @@ def identify_identifier
 
     if token[0, 1] =~ /[A-Z]/
       if token[-1] =~ /[!?]/
-        return Token(TkIDENTIFIER, token)
+        token_c = TkIDENTIFIER
       else
-        return Token(TkCONSTANT, token)
+        token_c = TkCONSTANT
       end
     elsif token[token.size - 1, 1] =~ /[!?]/
-      return Token(TkFID, token)
+      token_c = TkFID
     else
-      if peek(0) == ':' and !peek_match?(/^::/)
-        token.concat getc
-        return Token(TkSYMBOL, token)
-      else
-        return Token(TkIDENTIFIER, token)
-      end
+      token_c = TkIDENTIFIER
+    end
+    if peek(0) == ':' and !peek_match?(/^::/)
+      token.concat getc
+      return Token(TkSYMBOL, token)
+    else
+      return Token(token_c, token)
     end
   end