Sets context as the new current ImplicitCtxt for the duration of the function f.
Allows access to the TyCtxt in the current ImplicitCtxt.
Panics if there is no ImplicitCtxt available.
Allows access to the current ImplicitCtxt.
Panics if there is no ImplicitCtxt available.
Allows access to the current ImplicitCtxt in a closure if one is available.
Allows access to the TyCtxt in the current ImplicitCtxt.
The closure is passed None if there is no ImplicitCtxt available.
Allows access to the current ImplicitCtxt whose tcx field is the same as the tcx argument
passed in. This means the closure is given an ImplicitCtxt with the same 'tcx lifetime
as the TyCtxt passed in.
This will panic if you pass it a TyCtxt which is different from the current
ImplicitCtxt’s tcx field.