> Don’t underestimate erasure. Theories for free is a useful thing.
Indeed, phantom types are wildly underappreciated. Long ago, I created an library [1] that ensures the type safety of any runtime generated programs you create using it. It does this by typing the various stacks that are in play at any given time, but every new generic type on the CLR ends up creating new type descriptors in global data structures (which aren't GC'd), so complex programs with deep stacks end up generating a lot of static, uncollectable data that just hangs around forever.
Indeed, phantom types are wildly underappreciated. Long ago, I created an library [1] that ensures the type safety of any runtime generated programs you create using it. It does this by typing the various stacks that are in play at any given time, but every new generic type on the CLR ends up creating new type descriptors in global data structures (which aren't GC'd), so complex programs with deep stacks end up generating a lot of static, uncollectable data that just hangs around forever.
[1] http://higherlogics.blogspot.com/2008/11/embedded-stack-lang...