Note: There is a known bug in the current version when directives appear within then clauses of if blocks that causes Shellcheck to report SC1072 on otherwise valid code. Avoid using directives within then clauses - instead place them at the top of the if block or another enclosing block. This is fixed on the online version and the next release.
See Parser Error.
ShellCheck is a static analysis tool for shell scripts. This page is part of its documentation.