Check that the implicit cast from `id` used to construct the element
variable in an ObjC for-in statement is valid.
This check is included as part of a new `objc-cast` sanitizer, outside
of the main 'undefined' group, as (IIUC) the behavior it's checking for
is not technically UB.
The check can be extended to cover other kinds of invalid casts in ObjC.
Partially addresses: rdar://12903059, rdar://9542496
Differential Revision: https://reviews.llvm.org/D71491
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).
llvm-svn: 91446