Two slurs that overlap in note-range must nest with visibly different curve depths, not coincide

When one slur (a phrase mark) and another (a shorter articulation slur) cover overlapping note ranges, the outer slur must be drawn with visibly greater depth than the inner one.

A phrase slur over 8 notes and a shorter slur over notes 3-5 (nested inside it) render with near-identical sag and their curves visually merge across notes 3-5.

Gould, Behind Bars, ch. 'Ties and slurs' — nested slur depth convention; standard in Dorico/LilyPond as an explicit collision-avoidance case for coincident slurs.

This rule needs the notated content and the rendered result together — the score says what should happen, the page says whether it did.