The 80286 (and above) were segmented architectures where automatic bounds checking of each segment (which could hold an array, or code for that matter) was done

The 80286 (and above) were segmented architectures where automatic bounds checking of each segment (which could hold an array, or code for that matter) was done invisibly in hardware. The segmented nature of the 80286 (or even the 8088, predecessor of the 80286, which had segments but no automatic checks) was ... not universally liked (mainly because of a 64K limit, but even when the 80386 upped that, not many systems took advantage of it). The Intel 432 (developed in the very early 80s) had automatic bounds checking. The architecture as a whole failed because it was too complex, too slow, and too buggy to be viable.