AutosarC++18_03-A13.2.2

A binary arithmetic operator and a bitwise operator shall return a “prvalue”

Required inputs: IR

Binary arithmetic and bitwise operators should return a basic value (an unqualified, non-pointer, non-reference type) rather than pointers, references, or qualified types. Returning a reference to a member or a const-qualified value results in hard-to-use interfaces and can cause unexpected behavior.

Bad code (returning reference to member):

class MyInt {
    int value_;
public:
    int& operator+(int rhs) {  // ERROR: returns reference to member
        value_ += rhs;
        return value_;
    }
};

Bad code (returning const qualified):

class MyInt {
    int value_;
public:
    const int operator+(int rhs) {  // ERROR: returns const int
        return value_ + rhs;
    }
};

Good code (returning basic value):

class MyInt {
    int value_;
public:
    int operator+(int rhs) { return value_ + rhs; }  // OK: returns by value
};

Possible Messages

Key	Text	Severity	Disabled
arith_bitwise_basic_value	Binary arithmetic or bitwise operator shall return a basic value.	None	False

Options

• This rule shares the following common options: exclude_in_macros, exclude_messages_in_system_headers, excludes, extend_exclude_to_macro_invocations, includes, justification_checker, languages, post_processing, provider, report_at, severity

• The following places define options that affect this rule: Stylechecks, Analysis-GlobalOptions

allow_bitwise_shift

allow_bitwise_shift : bool = True

Whether to allow non-basic values for operator>> or operator<<.