== Why is this an issue?

Having two branches in the same ``++if++`` structure  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 they should be combined.

=== Noncompliant code example

[source,python]
----
if 0 <= a < 10:
    do_first()
    do_second()
elif 10 <= a < 20:
    do_the_other_thing()
elif 20 <= a < 50:
    do_first()         # Noncompliant; duplicates first condition
    do_second()  
----

=== Exceptions

Blocks in an ``++if++`` chain that contain a single line of code are ignored.


----
if 0 <= a < 10:
    do_first()
elif 10 <= a < 20:
    do_the_other_thing()
elif 20 <= a < 50:
    do_first()         # no issue, usually this is done on purpose to increase the readability
----

But this exception does not apply to ``++if++`` chains without ``++else++``-s when all branches have the same single line of code. In case of ``++if++`` chains with ``++else++``-s rule S3923 raises a bug. 

----
if 0 <= a < 10:
    do_first()
elif 20 <= a < 50:
    do_first()         # Noncompliant, this might have been done on purpose but probably not
----

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== Implementation Specification
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== Comments And Links
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