https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79501
eracpp at eml dot cc changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |eracpp at eml dot cc --- Comment #1 from eracpp at eml dot cc --- Still observed on trunk (GCC 9.0.0 20180722): https://wandbox.org/permlink/vpY98XCvEz2k0IN9 Relevant paragraph from the standard ([temp.deduct.guild]-3): http://eel.is/c++draft/temp.deduct.guide#3.sentence-4 "A deduction-guide shall be declared in the same scope as the corresponding class template and, for a member class template, with the same access."