struct ScriptObjectFixture
{
    static const int code_size;
    static const char code[];
    static wchar_t uc_code[];

    ScriptObjectFixture()
    {
        for (int i = 0; i < code_size; i++)
            uc_code[i] = 0;
    }

};

const char ScriptObjectFixture::code[] = "x";
const int ScriptObjectFixture::code_size = sizeof(ScriptObjectFixture::code) - 1;
wchar_t ScriptObjectFixture::uc_code[ScriptObjectFixture::code_size];


$ g++ w.cc -c  -Wsign-compare
w.cc:17:68: error: size of array ‘uc_code’ is not an integral constant-expression
 wchar_t ScriptObjectFixture::uc_code[ScriptObjectFixture::code_size];
                                                                    ^

Without -Wsign-compare there's no diagnostic.

Caused by r230365