std::experimental::ranges::IndirectUnaryInvocable, std::experimental::ranges::

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Experimental
Technical Specification
Filesystem library (filesystem TS)
Library fundamentals (library fundamentals TS)
Library fundamentals 2 (library fundamentals TS v2)
Library fundamentals 3 (library fundamentals TS v3)
Extensions for parallelism (parallelism TS)
Extensions for parallelism 2 (parallelism TS v2)
Extensions for concurrency (concurrency TS)
Extensions for concurrency 2 (concurrency TS v2)
Concepts (concepts TS)
Ranges (ranges TS)
Reflection (reflection TS)
Mathematical special functions (special functions TR)
Experimental Non-TS
Pattern Matching
Linear Algebra
std::execution
Contracts
2D Graphics
template < class F, class I >

concept bool IndirectUnaryInvocable =
    Readable<I> && CopyConstructible<F> &&
    Invocable<F&, ranges:: value_type_t <I> & > &&
    Invocable<F&, ranges:: reference_t <I>> &&
    Invocable<F&, ranges:: iter_common_reference_t <I>> &&
    CommonReference<
std::result_of_t <F& (ranges:: value_type_t <I> & ) >,

std::result_of_t <F& (ranges:: reference_t <I> && ) >> ;
(ranges TS)
template < class F, class I >

concept bool IndirectRegularUnaryInvocable =
    Readable<I> && CopyConstructible<F> &&
    RegularInvocable<F&, ranges:: value_type_t <I> & > &&
    RegularInvocable<F&, ranges:: reference_t <I>> &&
    RegularInvocable<F&, ranges:: iter_common_reference_t <I>> &&
    CommonReference<
std::result_of_t <F& (ranges:: value_type_t <I> & ) >,

std::result_of_t <F& (ranges:: reference_t <I> && ) >> ;
(ranges TS)