Function overwrite_tile 

pub fn overwrite_tile(
    tile: &mut OverwriteTile<'_>,
    rgba: &[u8],
    img_width: i64,
    blocks: &[(i64, i64)],
    ox: i64,
    oy: i64,
    tx: i64,
    ty: i64,
    frame: u32,
    confidence: f64,
    stable: bool,
) -> OverwriteStats

Mirrors Compositor.overwritePatch’s per-tile inner loop (src/core/compositor.ts): unconditionally copies every pixel of blocks (absolute block coordinates already restricted to this tile) from rgba into the tile, marking coverage, healing any provisional bit, and bumping owner/quality/conflicts/frozen evidence. The caller (resolveTemporal) has already proven the whole written set world-consistent (maskComplete) before calling this, so every pixel here is guaranteed in-bounds — this mirrors, not re-derives, that guarantee.