`pprTrace*` should be in GHC.Prelude
A recent change moved
pprTrace* to its own module
GHC.Driver.Ppr. A common pattern in GHC is to comment out (rather than delete)
pprTrace calls useful for printf-debugging information so one can re-use them at a later time.
That pattern now has become very cumbersome, because modules rarely have live calls to
pprTrace and hence the module import for
GHC.Driver.Ppr is redundant, so no code passing the validate flavour will have these imports and I have to add them everytime I need them. When I'm done debugging, I usually comment out the
pprTrace calls again. But now I also have to remove the import again, because otherwise it won't pass validate.
Hence it should be available from
GHC.Prelude or some other prominent module, like it used to be.