Re: declare checks on valid nameref names don't account for +=

[Grisha Levit]

Also seems like after an invalid nameref assignment is encountered, declare works oddly on remaining assignments that are part of the same command:

$ unset -n bad good
$ declare -n bad+=. good=var
bash: declare: `.': not a valid identifier
$ declare -p good
declare -- good="var"    # created, but not a nameref

$ unset -n bad good
$ declare -n good=var; declare -n bad+=. good=foo
bash: declare: `.': not a valid identifier
$ declare -p good
declare -n good="var"    # not modified

$ unset -n bad good
$ declare -n good=var; declare -n bad+=. good=var
bash: declare: `.': not a valid identifier
bash: var: nameref variable self references not allowed   # ??

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