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Suspicious back reference

Reports back references that will not be resolvable at runtime. This means that the back reference can never match anything. A back reference will not be resolvable when the group is defined after the back reference, or if the group is defined in a different branch of an alternation.

Example of a group defined after its back reference:

\1(abc)

Example of a group and a back reference in different branches:

a(b)c|(xy)\1z

New in 2022.1

Last modified: 29 April 2024