# errors on nil coalesce if lhs non-nilable

class Nilable

	def main
		a = 0
		
		b = a ? 99 # .error. The left hand type of "?" is not nilable
		assert  b == 0
		a = 10
		b = a ? 99 # .error. The left hand type of "?" is not nilable
		assert  b == 10
	
		a ?= 47 # .error. The left hand type of "?=" is not nilable
		assert b == 10
		
		s = 'yy'
		assert s ? 'xxx' == 'yy' # .error. The left hand type of "?" is not nilable
		
		s ?= 'xxx' # .error. The left hand type of "?=" is not nilable
		assert s == 'yy'