Having two ``++cases++`` in a ``++match++`` statement or two branches in an ``++if++`` chain with the same implementation is at best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then in an ``++if++`` chain they should be combined, or for a ``++match++``, one should fall through to the other.
Blocks in an ``++if++`` chain that contain a single line of code are ignored, as are blocks in a ``++match++`` statement that contain a single line of code.
But this exception does not apply to ``++if++`` chains without ``++else++``-s, or to ``++match++``-es without default clauses when all branches have the same single line of code. In case of ``++if++`` chains with ``++else++``-s, or of ``++match++``-es with default clauses, rule S3923 raises a bug.