src/doc/rustc-guide/src/traits/regions.md

   1 # Region constraints
   2
   3 *To be written.*
   4
   5 Chalk does not have the concept of region constraints, and as of this
   6 writing, work on rustc was not far enough to worry about them.
   7
   8 In the meantime, you can read about region constraints in the
   9 [type inference](../type-inference.html#region-constraints) section.