id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
13136,Regression: intrusive::unordered_set::rehash now requires T to be hashable,gromer@…,Ion Gaztañaga,"It is possible to create an `intrusive::unordered_set<T>` where `T` is not hashable, so long as you never use methods that perform hashing (e.g. insertion is performed via `insert_check` and `insert_commit`, and lookup is performed with a caller-specified hasher). `rehash` is documented as not calling the hash function if `store_hash` is true, so it ought to be callable on a set with that option enabled, and as of Boost 1.60.0 it was. However, as of Boost 1.64.0 calls to `rehash` on such a set no longer compile, because the generated code now includes a call to the hash function (which will never actually be executed).

Suggested fix: make `do_full_rehash` a non-type template parameter rather than a function parameter of `rehash_impl`, and encapsulate the `if(do_full_rehash)` logic behind a function template that takes `do_full_rehash` as a template argument (with the two branches as different specializations). That way the code that calls the hash function will not be generated unless the user actually calls `full_rehash`.",Bugs,new,To Be Determined,intrusive,Boost 1.64.0,Problem,,,fdegros@…