I don't know if this is intended, but before this commit for the following code:

struct SomeClass{
	std::string name;
	NonClass test;
}

void test(const std::vector<SomeClass>& t){
	for(const auto entry : t){
		std::cout << entry.name << std::endl;
	}
}

the following warning was emitted.

example_loop.cpp:7:17: performance: Range variable 'entry' should be declared as const reference. [iterateByValue]

After this commit you don't get the warning anymore. You only get it if you remove or comment out the line 3 NonClass test;.
It seems to me that the size of the whole class becomes zero if the function can not determine the size of one of it members in comparison to earlier where it seems that such a member was simply ignored.

I don't know if this is intended, but before this commit for the following code:

This is tracked in https://trac.cppcheck.net/ticket/13696