bugprone-unintended-char-ostream-output

Finds unintended character output from unsigned char and signed char to an ostream.

Normally, when unsigned char (uint8_t) or signed char (int8_t) is used, it is more likely a number than a character. However, when it is passed directly to std::ostream’s operator<<, the result is the character output instead of the numeric value. This often contradicts the developer’s intent to print integer values.

uint8_t v = 65;
std::cout << v; // output 'A' instead of '65'

The check will suggest casting the value to an appropriate type to indicate the intent, by default, it will cast to unsigned int for unsigned char and int for signed char.

std::cout << static_cast<unsigned int>(v); // when v is unsigned char
std::cout << static_cast<int>(v); // when v is signed char

To avoid lengthy cast statements, add prefix + to the variable can also suppress warnings because unary expression will promote the value to an int.

std::cout << +v;

Or cast to char to explicitly indicate that output should be a character.

std::cout << static_cast<char>(v);

CastTypeName

When CastTypeName is specified, the fix-it will use CastTypeName as the cast target type. Otherwise, fix-it will automatically infer the type.