Identify Trap in Signed vs Unsigned Comparison

Code

#include <stdio.h>
#include <stdint.h>

int safe_compare(int8_t a, uint8_t b) {
    // Your logic here
    if(a > 127) {
        a = -a;
        return a < b;
    }
    return a < b;
}

int main() {
    int8_t a;
    uint8_t b;
    scanf("%hhd %hhu", &a, &b);
    printf("%d", safe_compare(a, b));
    return 0;
}