So that `yield expr_with_error` will cause the error from the
argument rather than `LocalJumpError` when no block is given.

Otherwise line number information is lacked from exceptions
raised in VM, e.g. "super called outside of method".

ref #1359 #1362

Fix an off-by-one causing a buffer overflow in mirb.

One for the receiver, the other for the block.

Find Class/Module in nested singleton class; fix #3598

Did not update the result from `mrb_check_string_type()` before
string-to-integer conversion.

The fix for #3539 was incomplete.

GC may be called with OP_ENTER (especially when GC_STRESS is set).

VM stack is cleared by 5c114c91, 0cb501 and c063641a.

Otherwise, the following script prints an uninitialized value.

def f(*a)
  if false
    b = 15
  end
  p b
end
f(1,2,3)

Attach a name to  embbeded value of rescue/ensure stack size

Get constant of parent class even if child class is defined in signle…