'x is P' works now, and this function isn't used anywhere except by a test that exercises it. Removing this also lets us remove a swath of otherwise unused helper static functions in the runtime.
Swift SVN r26618
Teach ExistentialTypeMetadata how to project out the value pointer, type metadata, and protocol witness table from ErrorType containers. NFC yet; the dynamic casting and reflection machinery needs further work to correctly handle ErrorType boxes.
Swift SVN r26509
First, on x86-64 Linux does not reserve lower 2 Gb of the address space,
and a space saving trick in the runtime did not work properly, confusing
pointers and failure generation numbers together.
Second, we ignored protocol conformances inside the executable (only
considered shared libraries).
Swift SVN r25972
The standard library has grown significantly, and we need a new
directory structure that clearly reflects the role of the APIs, and
allows future growth.
See stdlib/{public,internal,private}/README.txt for more information.
Swift SVN r25876
