This revision generalizes the functionality currently present in FunctionPass, i.e.
running a pass on symbol definitions not declarations. This allows for removing the
dependency on FuncOp from Pass, and also more easily support non-FuncOp
function definition passes.
The definition of FunctionPass is left intact for now to allow time for downstream
users to migrate.
This makes the sentence less clear to me.
What about "Constants are defined in per-region pool (for example for a given function body), ..."