Introduce the clang pragmas "assume_nonnull begin" and "assume_nonnull
end" in which we make default assumptions about the nullability of many
unannotated pointers:
- Single-level pointers are inferred to __nonnull
- NSError** in a (function or method) parameter list is inferred to
NSError * __nullable * __nullable.
- CFErrorRef * in a (function or method) parameter list is inferred
to CFErrorRef __nullable * __nullable.
- Other multi-level pointers are never inferred to anything.
Implements rdar://problem/19191042.
llvm-svn: 240156
Douglas Gregor