MISRA C:2012 Rule 10.5

The value of an expression should not be cast to an inappropriate essential type

Description

The value of an expression should not be cast to an inappropriate essential type.

Converting Between Variable Types

Some inappropriate explicit casts are:

In C99, the result of a cast of assignment to _Bool is always 0 or 1. This result is not necessarily the case when casting to another type which is defined as essentially Boolean.
A cast to an essential enum type may result in a value that does not lie within the set of enumeration constants for that type.
A cast from essential Boolean to any other type is unlikely to be meaningful.
Converting between floating and character types is not meaningful as there is no precise mapping between the two representations.

Some acceptable explicit casts are:

For more information on essential types, see Essential Types in MISRA C Rules 10.x.

Group: The Essential Type Model

Category: Advisory

AGC Category: Advisory

Following MISRA C:2012 Amendment 3, Polyspace^® reports violations of this rule for these conversions:

Converting from essentially Boolean types to essentially complex floating types.
Converting from essentially character types to essentially complex floating types.
Converting from essentially complex floating types to essentially Boolean types.
Converting from essentially complex floating types to essentially enumeration types.