Does the federal Constitution require state courts to apply retroactively decisions that narrow the scope of criminal laws?

QUESTION PRESENTED In Welch v. United States, 136 S.Ct. 1257 (2016), this Court adopted a functional test for retroactivity: courts must retroactively apply decisions with substantive functions, including decisions that narrow the scope of a criminal statute. In Byford v. State, 116 Nev. 215, 994 P.2d 700 (2000), the Nevada Supreme Court narrowed the scope of first-degree murder. But despite Welch, the Nevada courts still refuse to apply Byford retroactively. The question presented is: Following Welch, does the federal Constitution require state courts to apply retroactively decisions that narrow the scope of criminal laws? 1