Proposed resolution (October, 2015):

Change 3.55 [defns.signature.member.templ] as follows:

signature
<class member function template> name, parameter type list (9.3.4.6 [dcl.fct]), class of which the function is a member, cv-qualifiers (if any), ref-qualifier (if any), return type (if any), and template parameter list

[Adopted at the February, 2016 meeting.]

According to 3.55 [defns.signature.member.templ], the signature of a class member function template includes:

name, parameter type list (9.3.4.6 [dcl.fct]), class of which the function is a member, cv-qualifiers (if any), ref-qualifier (if any), return type, and template parameter list

However, a constructor template does not have a return type. This may be relevant to friend declaration matching.