solidity/test/libsolidity/syntaxTests/nameAndTypeResolution/475_implicit_conversion_disallowed.sol

contract C {
    function f() public returns (bytes4) {
        uint32 tmp = 1;
        return tmp;
    }
}
// ----
// TypeError 6359: (95-98): Return argument type uint32 is not implicitly convertible to expected type (type of first return variable) bytes4.