In a declaration whose declarator-id refers to a specialization of a function template, template argument deduction is performed to identify the specialization to which the declaration refers. Specifically, this is done for explicit instantiations, explicit specializations, and certain friend declarations. This is also done to determine whether a deallocation function template specialization matches a placement operator new ([basic.stc.dynamic.deallocation], [expr.new]). In all these cases, P is the type of the function template being considered as a potential match and A is either the function type from the declaration or the type of the deallocation function that would match the placement operator new as described in [expr.new]. The deduction is done as described in [temp.deduct.type].