How does Julia decide whether to inline a function across module boundaries?

Inlining across modules depends on visibility, function size, type stability, and compiler heuristics.

Julia's inliner evaluates whether the benefit of removing call overhead outweighs code bloat. Across module boundaries, additional constraints apply because the function may not be fully visible at compile time. If a function is small and type-stable, it is more likely to be inlined even across modules after inference.