The bug likely got checked in earlier than 5.2.15, that's just what I happened to be running when I ran into this.
$ declare -p BASH_VERSINFO declare -ar BASH_VERSINFO=([0]="5" [1]="2" [2]="15" [3]="3" [4]="release" [5]="x86_64-pc-cygwin") $ bashbug /usr/bin/bashbug: line 135: [: missing `]' /usr/bin/bashbug: line 137: [: missing `]' {at this point I'm inside my $EDITOR, and exited without making changes} /usr/bin/bashbug: You have not changed the subject from the default. /usr/bin/bashbug: Please use a more descriptive subject header. /usr/bin/bashbug: Type `y' to give up, and lose your bug report; /usr/bin/bashbug: type `n' to re-enter the editor. /usr/bin/bashbug: Do you want to give up? y $ The relevant lines are in a series of tests trying to find the correct editor executable: ..... elif [ -x /usr/bin/xemacs ]; then DEFEDITOR=xemacs elif [ -x /usr/bin/vim; then <---- DEFEDITOR=vim elif [ -x /usr/bin/gvim; then <---- DEFEDITOR=gvim elif [ -x /usr/bin/nano ]; then .....