bugprone-casting-through-void

Detects unsafe or redundant two-step casting operations involving void*.

Two-step type conversions via void* are discouraged for several reasons.

• They obscure code and impede its understandability, complicating maintenance.

• These conversions bypass valuable compiler support, erasing warnings related to pointer alignment. It may violate strict aliasing rule and leading to undefined behavior.

• In scenarios involving multiple inheritance, ambiguity and unexpected outcomes can arise due to the loss of type information, posing runtime issues.

In summary, avoiding two-step type conversions through void* ensures clearer code, maintains essential compiler warnings, and prevents ambiguity and potential runtime errors, particularly in complex inheritance scenarios.

Examples:

using IntegerPointer = int *;
double *ptr;

static_cast<IntegerPointer>(static_cast<void *>(ptr)); // WRONG
reinterpret_cast<IntegerPointer>(reinterpret_cast<void *>(ptr)); // WRONG
(IntegerPointer)(void *)ptr; // WRONG
IntegerPointer(static_cast<void *>(ptr)); // WRONG