Introducing a new RandomGeneratorRule

Author: szumal

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/RandomGeneratorRules.java

@@ -75,4 +75,19 @@ long after(RandomGenerator random, long bound) {
       return random.nextLong(bound);
     }
   }
+
+  /**
+   * Prefer {@link RandomGenerator#nextInt(int origin, int bound)} over more contrived alternatives.
+   */
+  static final class RandomGeneratorNextIntWithOrigin {
+    @BeforeTemplate
+    int before(RandomGenerator random, int a, int b) {
+      return Refaster.anyOf(a + random.nextInt(b));
+    }
+
+    @AfterTemplate
+    int after(RandomGenerator random, int a, int b) {
+      return random.nextInt(a, a + b);
+    }
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/RandomGeneratorRulesTestInput.java

@@ -27,4 +27,8 @@ ImmutableSet<Long> testRandomGeneratorNextLong() {
         (long) new SecureRandom().nextDouble(3L),
         Math.round(ThreadLocalRandom.current().nextDouble(4L)));
   }
+
+  ImmutableSet<Integer> testRandomGeneratorNextIntWithOrigin() {
+    return ImmutableSet.of(20 + new Random().nextInt(80));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/RandomGeneratorRulesTestOutput.java

@@ -26,4 +26,8 @@ ImmutableSet<Long> testRandomGeneratorNextLong() {
         new SecureRandom().nextLong(3L),
         ThreadLocalRandom.current().nextLong(4L));
   }
+
+  ImmutableSet<Integer> testRandomGeneratorNextIntWithOrigin() {
+    return ImmutableSet.of(new Random().nextInt(20, 20 + 80));
+  }
 }