Mostly the compiler won't catch violation of the storage association rules. Toolpack had a useful tool for strict F77 code which was a boon fixing stuff not to break with the Alliant compiler, which was the first one the project I inherited used that took advantage of the optimization opportunity. Possibly Cray's would have done, but hadn't been used for a while at that point.
The fact that people won't believe the rules exist, is a continual source of bug hunting in Fortran unfortunately. At least restrict is visible.
