Type-check buffers even if they're only passed to extern stages.
Type-check buffers even if they're only passed to extern stages.


Former-commit-id: 8ab089cbf9d1acbcfd4d268dcd24bb53ac6c37fd
darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,darkbuck/Halide,darkbuck/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide,Trass3r/Halide,Trass3r/Halide,darkbuck/Halide