Affected subclause: [algorithms.requirements]
The number and order of deducible template parameters for algorithm declarations
is now unspecified, instead of being as-declared.
Increase implementor freedom and allow some function templates
to be implemented as function objects with templated call operators.
Effect on original feature:
A valid C++ 2017 program that passes explicit template arguments to
algorithms not explicitly specified to allow such in this version of C++
may fail to compile or have undefined behavior.