A Select or a chain of If/Elseif statements is evaluated from top to bottom. At most, only one branch will
be executed: the first one with a condition that evaluates to true.
Therefore, duplicating a condition automatically leads to dead code. Usually, this is due to a copy/paste error. At best, it’s simply dead code and
at worst, it’s a bug that is likely to induce further bugs as the code is maintained, and obviously it could lead to unexpected behavior.
Noncompliant code example
C IF X = 1
C EXSR SR01
C ELSEIF X = 1 Noncompliant
C EXSR SR02
C ENDIF
/free
IF param = 1;
doX();
ELSEIF param = 2;
doY();
ELSEIF param = 1; // Noncompliant
doZ();
ENDIF;
SELECT;
WHEN param = 1;
doX();
WHEN param = 2;
doY();
WHEN param = 1; // Noncompliant
doZ();
ENDSL;
/end-free
Compliant solution
C IF X = 1
C EXSR SR01
C ELSEIF X = 2
C EXSR SR02
C ENDIF
/free
IF param = 1;
doX();
ELSEIF param = 2;
doY();
ELSEIF param = 3;
doZ();
ENDIF;
SELECT;
WHEN param = 1;
doX();
WHEN param = 2;
doY();
WHEN param = 3;
doZ();
ENDSL;
/end-free
