Introduce ImmutableEnumSetRules refaster rules

documentation-support/src/test/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListenerTest.java

@@ -10,7 +10,6 @@
 import com.google.auto.service.AutoService;
 import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Streams;
 import com.google.errorprone.VisitorState;
@@ -41,7 +40,8 @@ void readOnlyFileSystemWindows(@TempDir Path outputDirectory) throws IOException
                 entry ->
                     AclEntry.newBuilder(entry)
                         .setPermissions(
-                            Sets.difference(entry.permissions(), ImmutableSet.of(ADD_SUBDIRECTORY)))
+                            Sets.difference(
+                                entry.permissions(), Sets.immutableEnumSet(ADD_SUBDIRECTORY)))
                         .build())
             .collect(toImmutableList()));
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitClassModifiers.java

@@ -16,7 +16,7 @@
 import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
 
 import com.google.auto.service.AutoService;
-import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -70,7 +70,7 @@ public Description matchClass(ClassTree tree, VisitorState state) {
     SuggestedFixes.removeModifiers(
             tree.getModifiers(),
             state,
-            ImmutableSet.of(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC))
+            Sets.immutableEnumSet(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC))
         .ifPresent(fixBuilder::merge);
 
     if (!HAS_SPRING_CONFIGURATION_ANNOTATION.matches(tree, state)) {

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

@@ -0,0 +1,177 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Repeated;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.EnumSet;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with immutable {@link Enum} collections. */
+@OnlineDocumentation
+final class ImmutableEnumSetRules {
+  private ImmutableEnumSetRules() {}
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Iterable)} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetIterable<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Collection<T> elements) {
+      return ImmutableSet.copyOf(elements);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(Collection<T> elements) {
+      return Sets.immutableEnumSet(elements);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Iterable)} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetIterable1<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(T[] elements) {
+      return ImmutableSet.copyOf(elements);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T[] elements) {
+      return Sets.immutableEnumSet(Arrays.asList(elements));
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetOneElement<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("ImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1) {
+      return Refaster.anyOf(ImmutableSet.of(e1), ImmutableSet.copyOf(EnumSet.of(e1)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1) {
+      return Sets.immutableEnumSet(e1);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetTwoElements<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("ImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2) {
+      return Refaster.anyOf(ImmutableSet.of(e1, e2), ImmutableSet.copyOf(EnumSet.of(e1, e2)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2) {
+      return Sets.immutableEnumSet(e1, e2);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetThreeElements<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("ImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2, T e3) {
+      return Refaster.anyOf(
+          ImmutableSet.of(e1, e2, e3), ImmutableSet.copyOf(EnumSet.of(e1, e2, e3)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3) {
+      return Sets.immutableEnumSet(e1, e2, e3);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetFourElements<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("ImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2, T e3, T e4) {
+      return Refaster.anyOf(
+          ImmutableSet.of(e1, e2, e3, e4), ImmutableSet.copyOf(EnumSet.of(e1, e2, e3, e4)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4) {
+      return Sets.immutableEnumSet(e1, e2, e3, e4);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetFiveElements<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("ImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2, T e3, T e4, T e5) {
+      return Refaster.anyOf(
+          ImmutableSet.of(e1, e2, e3, e4, e5), ImmutableSet.copyOf(EnumSet.of(e1, e2, e3, e4, e5)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4, T e5) {
+      return Sets.immutableEnumSet(e1, e2, e3, e4, e5);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetSixElements<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(T e1, T e2, T e3, T e4, T e5, T e6) {
+      return ImmutableSet.of(e1, e2, e3, e4, e5, e6);
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4, T e5, T e6) {
+      return Sets.immutableEnumSet(e1, e2, e3, e4, e5, e6);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * internally used {@link EnumSet}.
+   */
+  static final class ImmutableEnumSetVarArgs<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("ImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, @Repeated T elements) {
+      return ImmutableSet.copyOf(EnumSet.of(e1, Refaster.asVarargs(elements)));
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1, @Repeated T elements) {
+      return Sets.immutableEnumSet(e1, Refaster.asVarargs(elements));
+    }
+  }
+}

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

@@ -43,6 +43,7 @@ final class RefasterRulesTest {
           EqualityRules.class,
           FileRules.class,
           InputStreamRules.class,
+          ImmutableEnumSetRules.class,
           ImmutableListRules.class,
           ImmutableListMultimapRules.class,
           ImmutableMapRules.class,

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

@@ -0,0 +1,89 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import java.math.RoundingMode;
+import java.util.EnumSet;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class ImmutableEnumSetRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<Object> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(EnumSet.class);
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetIterable() {
+    return ImmutableSet.of(
+        ImmutableSet.copyOf(EnumSet.range(RoundingMode.UP, RoundingMode.UNNECESSARY)),
+        ImmutableSet.copyOf(EnumSet.allOf(RoundingMode.class)));
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetIterable1() {
+    return ImmutableSet.of(
+        ImmutableSet.copyOf(RoundingMode.values()),
+        ImmutableSet.copyOf(RoundingMode.class.getEnumConstants()));
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetOneElement() {
+    return ImmutableSet.of(
+        ImmutableSet.of(RoundingMode.UP), ImmutableSet.copyOf(EnumSet.of(RoundingMode.UP)));
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetTwoElements() {
+    return ImmutableSet.of(
+        ImmutableSet.of(RoundingMode.UP, RoundingMode.DOWN),
+        ImmutableSet.copyOf(EnumSet.of(RoundingMode.UP, RoundingMode.DOWN)));
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetThreeElements() {
+    return ImmutableSet.of(
+        ImmutableSet.of(RoundingMode.UP, RoundingMode.DOWN, RoundingMode.CEILING),
+        ImmutableSet.copyOf(EnumSet.of(RoundingMode.UP, RoundingMode.DOWN, RoundingMode.CEILING)));
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetFourElements() {
+    return ImmutableSet.of(
+        ImmutableSet.of(
+            RoundingMode.UP, RoundingMode.DOWN, RoundingMode.CEILING, RoundingMode.FLOOR),
+        ImmutableSet.copyOf(
+            EnumSet.of(
+                RoundingMode.UP, RoundingMode.DOWN, RoundingMode.CEILING, RoundingMode.FLOOR)));
+  }
+
+  ImmutableSet<ImmutableSet<RoundingMode>> testImmutableEnumSetFiveElements() {
+    return ImmutableSet.of(
+        ImmutableSet.of(
+            RoundingMode.UP,
+            RoundingMode.DOWN,
+            RoundingMode.CEILING,
+            RoundingMode.FLOOR,
+            RoundingMode.UNNECESSARY),
+        ImmutableSet.copyOf(
+            EnumSet.of(
+                RoundingMode.UP,
+                RoundingMode.DOWN,
+                RoundingMode.CEILING,
+                RoundingMode.FLOOR,
+                RoundingMode.UNNECESSARY)));
+  }
+
+  ImmutableSet<RoundingMode> testImmutableEnumSetSixElements() {
+    return ImmutableSet.of(
+        RoundingMode.UP,
+        RoundingMode.DOWN,
+        RoundingMode.CEILING,
+        RoundingMode.FLOOR,
+        RoundingMode.UNNECESSARY,
+        RoundingMode.HALF_EVEN);
+  }
+
+  ImmutableSet<RoundingMode> testImmutableEnumSetVarArgs() {
+    return ImmutableSet.copyOf(
+        EnumSet.of(
+            RoundingMode.UP,
+            RoundingMode.DOWN,
+            RoundingMode.CEILING,
+            RoundingMode.FLOOR,
+            RoundingMode.UNNECESSARY,
+            RoundingMode.HALF_EVEN));
+  }
+}