private void pop(final int elements) {
        if (outputStackTop >= elements) {
            outputStackTop -= elements;
        } else {
            // If the number of elements to be popped is greater than the number of elements in the output
            // stack, clear it, and pop the remaining elements from the input stack.
            outputStackStart -= elements - outputStackTop;
            outputStackTop = 0;
        }
    }
Pops the given number of abstract types from the output frame stack.

@param elements the number of abstract types that must be popped.
core/src/main/java/com/alibaba/fastjson2/internal/asm/Frame.java