It queried for [transparent] [serialized] definitions and only had an effect
when the module was compiled with -Onone because we remove [serialized]
as part of the optimizer pipeline.
It was causing bad effects when the module we imported from was compiled
with -Onone:
The definition would be marked internal in said module.
and the importing module is compile with -O:
The definition would be marked as available_externally.
because neither would guaranteed the presence of a definition of the
imported symbol available to the importer.
rdar://35100697
Use the KeyPath implementation's new support for instantiating and dealing with captures to lower the generic context required to dispatch computed accessors with dependent generics.
Rather than pretend that the requirement signature of a protocol is a
full, well-formed generic signature that one can meaningfully query,
treat it as a flat set of requirements. Nearly all clients already did
this, but make it official. NFC
