[Bug c++/80380] New: misleading behavior with designated initializers for std::vector

[ethan at atdllc dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80380

            Bug ID: 80380
           Summary: misleading behavior with designated initializers for
                    std::vector
           Product: gcc
           Version: 6.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ethan at atdllc dot com
  Target Milestone: ---

Created attachment 41164
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=41164&action=edit
short example (not pre-processed)

Designated initializers are silently ignored when used in a initializer list
for a std::vector.

const std::vector<const char *>strings = {
    [ 0] = "zero",
    [ 1] = "one",
    [20] = "twenty",
};

This compiles silently, and results in a vector with three elements.

Using a std::array does result in an error (error: ‘[0] =’ used in a GNU-style
...), as does initializing an array of char * (sorry, unimplemented:
non-trivial designated initializers not supported).

If someone really wants a preprocessed .ii file, I can add one tuesday.