[Bug c++/87165] New: Did you mean hints candidates equality

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87165

            Bug ID: 87165
           Summary: Did you mean hints candidates equality
           Product: gcc
           Version: 9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: marxin at gcc dot gnu.org
                CC: dmalcolm at gcc dot gnu.org
  Target Milestone: ---

Hi David.

Richi pointed out that for some wrong options the hint is not ideal. Let's
consider:

./xgcc -B. -c /tmp/empty.c -std=c++19
xgcc: error: unrecognized command line option ‘-std=c++19’; did you mean
‘-std=c++11’?

Valid candidates with one character diff are:

-std=c++11
-std=c++14
-std=c++17
-std=c++1y
-std=c++1z

Maybe we can prioritize the biggest number? Or closest according to character
diffrence '9' - '7' ?