return n
	}

	op, why := assignOp(n.Type(), t)
	if op == ir.OXXX {
		base.Errorf("cannot use %L as type %v in %s%s", n, t, context(), why)
		op = ir.OCONV
	}

	r := ir.NewConvExpr(base.Pos, op, t, n)
	r.SetTypecheck(1)
	r.SetImplicit(true)
	return r
}

// Is type src assignment compatible to type dst?
// If so, return op code to use in conversion.