SA0077: Enumeration type mismatch with CASE expression

Detects code positions where a CASE statement mixes enumeration values with non-enumeration types.

Justification: Mixing enumeration values and integer values in CASE constructs violates data type safety, reduces the readability of the code, and impacts maintainability. Enumeration values ensure semantic clarity. Using of raw integer values carries the risk of minor errors and makes the code more difficult to understand. Data type changes to enumerations can also destroy integer-based branches which may go unnoticed.

Importance: Low

{attribute 'qualified_only'}
{attribute 'strict'}
TYPE DUT_MyEnum :
(
	One := 1, 
	Two := 2, 
	Three := 3, 
	Four := 4
);
END_TYPE

PROGRAM PRG_Case
VAR
diVar : DINT;
xTemp : BOOL;

eMyEnum : DUT_MyEnum;
END_VAR

CASE diVar OF
    1 :
        xTemp := FALSE;
    DUT_MyEnum.Two : // SA0077
        xTemp := TRUE;
    ELSE
        xTemp := NOT xTemp;
END_CASE

CASE eMyEnum OF
    1 : // SA0077
        xTemp := FALSE;
    DUT_MyEnum.Two:
        xTemp := TRUE;
    ELSE
        xTemp := NOT xTemp;
END_CASE