Purity.java

import org.checkerframework.dataflow.qual.Deterministic;
import org.checkerframework.dataflow.qual.Pure;
import org.checkerframework.dataflow.qual.SideEffectFree;
import org.checkerframework.framework.test.*;
import testlib.util.*;

// various tests for the @Pure annotation
class Purity {

    String f1, f2, f3;
    String[] a;

    // class with a (potentially) non-pure constructor
    private static class NonPureClass {}

    // class with a pure constructor
    private static class PureClass {
        @Pure
        //:: warning: (purity.deterministic.constructor)
        public PureClass() {}
    }

    // class with a side-effect-free constructor
    private static class SEClass {
        @SideEffectFree
        public SEClass() {}
    }

    // a method that is not pure (no annotation)
    void nonpure() {}

    @Pure
    String pure() {
        return "";
    }

    @Pure
    //:: warning: (purity.deterministic.void.method)
    void t1() {}

    @SideEffectFree
    void t1b() {}

    @Deterministic
    //:: warning: (purity.deterministic.void.method)
    void t1c() {}

    @Pure
    String t2() {
        return "";
    }

    @Pure
    String t3() {
        //:: error: (purity.not.deterministic.not.sideeffectfree.call)
        nonpure();
        //:: error: (purity.not.deterministic.call)
        t16b(); // Calling a @SideEffectFree method
        //:: error: (purity.not.sideeffectfree.call)
        t16c(); // Calling a @Deterministic method
        return "";
    }

    @Pure
    String t4() {
        pure();
        return "";
    }

    @Pure
    int t5() {
        int i = 1;
        return i;
    }

    @Pure
    int t6() {
        int j = 0;
        for (int i = 0; i < 10; i++) {
            j = j - i;
        }
        return j;
    }

    @Pure
    String t7() {
        if (true) {
            return "a";
        }
        return "";
    }

    @Pure
    int t8() {
        return 1 - 2 / 3 * 2 % 2;
    }

    @Pure
    String t9() {
        return "b" + "a";
    }

    @Pure
    String t10() {
        //:: error: (purity.not.deterministic.not.sideeffectfree.assign.field)
        f1 = "";
        //:: error: (purity.not.deterministic.not.sideeffectfree.assign.field)
        f2 = "";
        return "";
    }

    @Pure
    String t11(Purity l) {
        //:: error: (purity.not.deterministic.not.sideeffectfree.assign.array)
        l.a[0] = "";
        return "";
    }

    @Pure
    String t12(String[] s) {
        //:: error: (purity.not.deterministic.not.sideeffectfree.assign.array)
        s[0] = "";
        return "";
    }

    @Pure
    String t13() {
        //:: error: (purity.not.deterministic.object.creation)
        PureClass p = new PureClass();
        return "";
    }

    @SideEffectFree
    String t13b() {
        PureClass p = new PureClass();
        return "";
    }

    @SideEffectFree
    String t13d() {
        SEClass p = new SEClass();
        return "";
    }

    @Deterministic
    String t13c() {
        //:: error: (purity.not.deterministic.object.creation)
        PureClass p = new PureClass();
        return "";
    }

    @Pure
    String t14() {
        String i = "";
        i = "a";
        return i;
    }

    @Pure
    String t15() {
        String[] s = new String[1];
        return s[0];
    }

    @Pure
    String t16() {
        try {
            int i = 1 / 0;
            //:: error: (purity.not.deterministic.catch)
        } catch (Throwable t) {
            // ..
        }
        return "";
    }

    @SideEffectFree
    String t16b() {
        try {
            int i = 1 / 0;
        } catch (Throwable t) {
            // ..
        }
        return "";
    }

    @Deterministic
    String t16c() {
        try {
            int i = 1 / 0;
            //:: error: (purity.not.deterministic.catch)
        } catch (Throwable t) {
            // ..
        }
        return "";
    }

    @Pure
    String t12() {
        //:: error: (purity.not.deterministic.not.sideeffectfree.object.creation)
        NonPureClass p = new NonPureClass();
        return "";
    }

    @Deterministic
    String t17a(Purity l) {
        //:: error: (purity.not.deterministic.assign.field)
        f1 = "";
        //:: error: (purity.not.deterministic.assign.array)
        l.a[0] = "";
        //:: error: (purity.not.deterministic.call)
        nonpure();
        //:: error: (purity.not.deterministic.call)
        return t16b(); // Calling a @SideEffectFree method
    }

    @SideEffectFree
    String t17b() {
        //:: error: (purity.not.sideeffectfree.object.creation)
        NonPureClass p = new NonPureClass();
        //:: error: (purity.not.sideeffectfree.call)
        nonpure();
        //:: error: (purity.not.sideeffectfree.call)
        return t16c(); // Calling a @Deterministic method
    }

    // @Pure annotations on the overridden implementation.
    class Super {
        @Pure
        int m1(int arg) {
            return 0;
        }

        @Pure
        int m2(int arg) {
            return 0;
        }

        int m3(int arg) {
            return 0;
        }

        int m4(int arg) {
            return 0;
        }
    }

    class Sub extends Super {
        @Pure
        int m1(int arg) {
            return 0;
        }

        int m2(int arg) {
            return 0;
        }

        @Pure
        int m3(int arg) {
            return 0;
        }

        int m4(int arg) {
            return 0;
        }
    }

    class MyClass extends Object {
        public int hashCode() {
            return 42;
        }
    }
}