LUB.java

import org.checkerframework.checker.regex.qual.Regex;

public class LUB {

    void test1(@Regex(4) String s4, boolean b) {
        String s = null;
        if (b) {
            s = s4;
        }
        @Regex(4) String test = s;

        //:: error: (assignment.type.incompatible)
        @Regex(5) String test2 = s;
    }

    void test2(@Regex(2) String s2, @Regex(4) String s4, boolean b) {
        String s = s4;
        if (b) {
            s = s2;
        }
        @Regex(2) String test = s;

        //:: error: (assignment.type.incompatible)
        @Regex(3) String test2 = s;
    }

    void test3(@Regex(6) String s6, boolean b) {
        String s;
        if (b) {
            s = s6;
        } else {
            s = null;
        }
        @Regex(6) String test = s;

        //:: error: (assignment.type.incompatible)
        @Regex(7) String test2 = s;
    }

    void test4(@Regex(8) String s8, @Regex(9) String s9, boolean b) {
        String s;
        if (b) {
            s = s8;
        } else {
            s = s9;
        }
        @Regex(8) String test = s;

        //:: error: (assignment.type.incompatible)
        @Regex(9) String test2 = s;
    }

    void test5(@Regex(10) String s10, @Regex(11) String s11, boolean b) {
        String s;
        if (b) {
            s = s11;
        } else {
            s = s10;
            return;
        }
        // TODO: s is a @Regex(10) here, but shouldn't it be a @Regex(11)?
        // @Regex(11) String test = s;

        //:: error: (assignment.type.incompatible)
        @Regex(12) String test2 = s;
    }
}