Fix #16104
Previously thNameToGhcName
was calling lookupOrigNameCache
directly, which
failed to handle the case that the name wasn't already in the name cache. This
happens, for instance, when the name was in scope in a plugin being used during
compilation but not in scope in the module being compiled. In this case we the
interface file containing the name won't be loaded and lookupOrigNameCache
fails. This was the cause of #16104 (closed).
The solution is simple: use the nicely packaged lookupOrigIO
instead.
Edited by Ben Gamari