MISRA.CAST.INT.WIDER

Cast of floating point expression to a wider floating point type.

MISRA-C++ Rule 5-0-8 (required): An explicit integral or floating-point conversion shall not increase the size of the underlying type of a cvalue expression.

This rule is also covered by MISRA.CAST.FLOAT.WIDER.

Rationale

A cast applied to the result of an expression does not change the type in which the expression is evaluated, which may be contrary to developer expectations.

Example

void f ( )
{
   int16_t s16;
   int32_t s32;

   s32 = static_cast< int32_t > ( s16 + s16 );    // Non-compliant
   s32 = static_cast< int32_t > ( s16 ) + s16 ;   // Compliant
}

In the above example, the expression ( s16 + s16 ) is performed with an underlying type of 'int16_t' rather than 'int32_t'.