mruby/mruby — pull request #1667 by h2so5 (2014-01-30 01:09:38+00:00)
Title: more accurate backtrace lineno

Current backtrace does not indicate a beginning of statements.

```ruby
1 class A
2 module B
3 [1].each do |x|
4 a
5 end
6 end
7 end
```

```
trace:
[4] test.rb:4:in A::B.call
[3] mrblib/array.rb:21:in Array.each
[2] test.rb:5
[1] test.rb:6
[0] test.rb:7
test.rb:4: undefined method 'a' for A::B (NoMethodError)
```

In this patch, ```parser_state``` holds beginning lineno as ```beg_lineno```.
```
trace:
[4] test.rb:4:in A::B.call
[3] mrblib/array.rb:21:in Array.each
[2] test.rb:3
[1] test.rb:2
[0] test.rb:1
test.rb:4: undefined method 'a' for A::B (NoMethodError)
```