# The real visitor that does the real job
private class DivByZeroVisitor
	super Visitor

	# The toolcontext is our entree point to most services
	var toolcontext: ToolContext

	# The mmodule is the current module
	var mmodule: MModule

	redef fun visit(node)
	do
		# Recursively visit all sub-nodes
		node.visit_all(self)

		# Now just filter out until we get what we want...

		# 1. We need a `/` operation
		if not node isa ASlashExpr then return

		# 2. The second operand must be an integer literal
		var op2 = node.n_expr2
		if not op2 isa AIntegerExpr then return

		# 3. Its value must be 0
		# Note: because of `literal_phase` the `value` method exists
		if op2.value != 0 then return

		# 4. The receiver (first operand) must be an Int
		var op1 = node.n_expr
		var int_type = mmodule.get_primitive_class("Int").mclass_type
		if not op1.mtype.is_subtype(mmodule, null, int_type) then return

		# Error detected
		toolcontext.warning(node.location, "div-by-zero", "Warning: division by zero.")
	end
end