6 Basics [basic]

6.4 Scope [basic.scope]

6.4.10 Contract-assertion scope [basic.scope.contract]

Each contract assertion ([basic.contract]) C introduces a contract-assertion scope that includes C.
If a result-name-introducer ([dcl.contract.res]) that is not name-independent ([basic.scope.scope]) and whose enclosing postcondition assertion is associated with a function F potentially conflicts with a declaration whose target scope is the program is ill-formed.