A tie must not be authored across a repeat sign or into a first/second ending

A tie implies the immediately next SOUNDING note in performance order; a repeat barline is a structural jump, so a note tied 'into' a repeat does not reliably sustain into whatever plays next. Standard practice never ties across a repeat sign — a pitch that must continue through a repeat is re-articulated as a fresh tied pair after the repeat resolves.

Gould and general engraving convention: ties do not span repeat barlines or into first/second endings. Ross likewise treats repeat structure as a hard boundary for continuous marks (ties, slurs, hairpins).

This rule can be decided from pitches, durations and voices — no layout required. A validator can check it before anything is drawn.