[RFC] type safe trees

[Geoffrey Keating]

Neil Booth <neil@daikokuya.co.uk> writes:

> We really need front-end specific data structures, lowered to a common
> representation (I suspect gimple).  It would even solve the current
> Kenner thread, though he may disagree.  Leave front ends to mind
> their own business; then if I fix things in C I don't have to worry
> about breaking something in Ada about which I have absolutely no clue.
> 
> Of course, it's a massive amount of work to do this, given how trees
> are now grossly intertwined with GC and PCH.  However, I think we're
> doing GC and PCH wrong too, and it's all just different manifestations
> of the same fundamental problem.

What part of the interaction between trees, GC, and PCH, prevents you from
creating new data structures for the frontend?