dangerousTypeCast

Message: Potentially invalid type conversion in old-style C cast, clarify/fix with C++ cast

Category: Type Safety

Severity: Warning

Language: C++, not applicable for C code

Motivation

C style casts can be dangerous in many ways:

• loss of precision
• loss of sign
• loss of constness
• invalid type conversion

Philosophy

This checker warns about old style C casts that perform type conversions that can be invalid.

This checker is not about readability. It is about safety.

How to fix

You can use dynamic_cast or static_cast to fix these warnings.

Before:

struct Base{};
struct Derived: public Base {};
void foo(Base* base) {
    Derived *p = (Derived*)base; // <- can be invalid
}

After:

struct Base{};
struct Derived: public Base {};
void foo(Base* base) {
    Derived *p = dynamic_cast<Derived*>(base);
}