s = types.BuiltinPkg.Lookup("false")
	s.Def = ir.NewConstAt(src.NoXPos, s, types.UntypedBool, constant.MakeBool(false))

	s = Lookup("_")
	types.BlankSym = s
	ir.BlankNode = ir.NewNameAt(src.NoXPos, s, types.Types[types.TBLANK])
	s.Def = ir.BlankNode

	s = types.BuiltinPkg.Lookup("_")
	s.Def = ir.NewNameAt(src.NoXPos, s, types.Types[types.TBLANK])

	s = types.BuiltinPkg.Lookup("nil")
	s.Def = NodNil()