If you overspecify, you close the door to better implementations. This is why, for example, C++ standard hash tables and regexes are an order of magnitude slower than third party ones.
The standard didn't say "you must implement std::unordered_map as a hash table with chained buckets and extra memory allocations", but ithe standard specified several guarantees that make it very difficult to implement hash tables with open addressing.
Every constraint that you specify potentially locks out a better implementation.
For recursive rwlocks, there's a lot of ways to implement them. Do you want to lock out high performance implementations that do less error checking, for example?
The standard didn't say "you must implement std::unordered_map as a hash table with chained buckets and extra memory allocations", but ithe standard specified several guarantees that make it very difficult to implement hash tables with open addressing.
Every constraint that you specify potentially locks out a better implementation.
For recursive rwlocks, there's a lot of ways to implement them. Do you want to lock out high performance implementations that do less error checking, for example?