[Bug c++/69600] New: Incorrect use of copy-assignment instead of move assignment from function

[sshannin at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69600

            Bug ID: 69600
           Summary: Incorrect use of copy-assignment instead of move
                    assignment from function
           Product: gcc
           Version: 5.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: sshannin at gmail dot com
  Target Milestone: ---

Created attachment 37541
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=37541&action=edit
preprocessed source

In some cases, it looks like the copy assignment operator is being used to
store return values from a function instead of the move assignment operator.

This causes the compilation to fail because it tries to use the copy-assignment
operator of some classes which may be movable only (unique_ptr).

Note that changing data_t to be either 'std::map<int, inner_data>' or
'std::map<int, value_t>' allows the code to compile.

Let me know if I can provide any more details that would be helpful.

gcc-5.3.0
x86_64-unknown-linux-gnu