Division.java

import org.checkerframework.checker.units.*;
import org.checkerframework.checker.units.qual.*;

public class Division {
    void d() {
        // Basic division of same units, no units constraint on x
        @m int am = 6 * UnitsTools.m, bm = 3 * UnitsTools.m;
        int x = am / bm;

        //:: error: (assignment.type.incompatible)
        @m int bad = am / bm;

        // Division removes the unit.
        // As unqualified would be a supertype, we add another multiplication
        // to make sure the result of the division is unqualified.
        @s int div = (am / UnitsTools.m) * UnitsTools.s;

        // units setup
        @m int m = 2 * UnitsTools.m;
        @mm int mm = 8 * UnitsTools.mm;
        @km int km = 4 * UnitsTools.km;
        @s int s = 3 * UnitsTools.s;
        @h int h = 5 * UnitsTools.h;
        @m2 int m2 = 25 * UnitsTools.m2;
        @km2 int km2 = 9 * UnitsTools.km2;
        @mm2 int mm2 = 16 * UnitsTools.mm2;
        @mPERs int mPERs = 20 * UnitsTools.mPERs;
        @kmPERh int kmPERh = 2 * UnitsTools.kmPERh;
        @mPERs2 int mPERs2 = 30 * UnitsTools.mPERs2;

        // m / s = mPERs
        @mPERs int velocitym = m / s;
        //:: error: (assignment.type.incompatible)
        velocitym = m / h;

        // km / h = kmPERh
        @kmPERh int velocitykm = km / h;
        //:: error: (assignment.type.incompatible)
        velocitykm = km / s;

        // m2 / m = m
        @m int distancem = m2 / m;
        //:: error: (assignment.type.incompatible)
        distancem = m2 / km;

        // km2 / km = km
        @km int distancekm = km2 / km;
        //:: error: (assignment.type.incompatible)
        distancekm = km2 / m;

        // mm2 / mm = mm
        @mm int distancemm = mm2 / mm;
        //:: error: (assignment.type.incompatible)
        distancemm = km2 / mm;

        // m / mPERs = s
        @s int times = m / mPERs;
        //:: error: (assignment.type.incompatible)
        times = km / mPERs;

        // km / kmPERh = h
        @h int timeh = km / kmPERh;
        //:: error: (assignment.type.incompatible)
        timeh = m / kmPERh;

        // mPERs / s = mPERs2
        @mPERs2 int accel1 = mPERs / s;
        //:: error: (assignment.type.incompatible)
        accel1 = kmPERh / s;

        // mPERs / mPERs2 = s
        @s int times2 = mPERs / mPERs2;
        //:: error: (assignment.type.incompatible)
        times2 = kmPERh / mPERs2;
    }

    void SpeedOfSoundTests() {
        @mPERs double speedOfSound = (340.29 * UnitsTools.m) / (UnitsTools.s);

        @s double tenSeconds = 10.0 * UnitsTools.s;
        @m double soundIn10Seconds = speedOfSound * tenSeconds;

        @m double length = 100.0 * UnitsTools.m;
        @s double soundNeedTimeForLength = length / speedOfSound;
    }
}