Silent typed holes
I have a UI feature request for -fwarn-typed-holes, currently there's two options: 1) typed holes are on (default) and GHC prints errors for types holes or 2) typed holes are off and GHC will print "not in scope" error and prematurely end compilation.
When writing haskell, I frequently want to typecheck my code before it's completely implemented. Before I used undefined/error, which worked but I was always worried about accidentally forgetting an undefined somewhere. With typed holes this is no longer a problem, but unfortunately the warnings from typed holes are so verbose they drown out the other type errors. This makes typechecking during refactoring rather onerous.
I propose adding a -fsilent-typed-holes and/or -ftreat-type-holes-as-undefined which enable typed holes, but silence any compile time warnings. It'd be nice if this flag treated holes as if "-fdefer-type-errors" was on, but ONLY for typed holes.
This would let me compile the code and fix warnings, ignoring the holes while developing, while still assuring that, when I remove the flag and compile "for real" I get an error about typed holes.