Insufficient in-scope-sets

I found two spots where we were making insufficient InScopeSets (while updating singletons for 8.0), in mkCastTy and mkWWargs.

I don't have a reduced test case for either; if you really want one, just try compiling singletons once it's updated.

Fix en route.

Trac metadata

Trac field	Value
Version	8.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture

changed weight to 5

added Tbug Trac import labels

This should be merged -- it's needed to compile singletons on GHC8. Thanks!

added 1 deleted label

mentioned in commit 0b6dcf6d

changed milestone to %8.0.1

mentioned in commit 8d66765c

closed

Merged as 6d1d9792 (comment:1) and b3321ca7 (comment:2).

Trac metadata

Trac field	Value
Resolution	Unresolved → ResolvedFixed

removed 1 deleted label

added Pnormal label