/*
 * Copyright 2013-present Facebook, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may
 * not use this file except in compliance with the License. You may obtain
 * a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 */

package com.facebook.buck.rules;

import com.google.common.base.Preconditions;
import java.util.Objects;

/** Abstract base class for implementations of {@link SourcePath}. */
abstract class AbstractSourcePath<T extends AbstractSourcePath<T>> implements SourcePath {

  /** @return An opaque representation of the source path in a stable manner. */
  protected abstract Object asReference();

  protected abstract int compareReferences(T o);

  @SuppressWarnings("unchecked")
  @Override
  public int compareTo(SourcePath o) {
    if (o == this) {
      return 0;
    }

    if (this.getClass() != o.getClass()) {
      int result = this.getClass().getName().compareTo(o.getClass().getName());
      if (result != 0) {
        return result;
      }

      Preconditions.checkState(
          this.getClass().equals(o.getClass()), "Classes are different but have the same name.");
    }

    return this.compareReferences((T) o);
  }

  @Override
  public int hashCode() {
    return asReference().hashCode();
  }

  @Override
  public boolean equals(Object other) {
    if (other == null || !(other instanceof AbstractSourcePath)) {
      return false;
    }

    AbstractSourcePath<?> that = (AbstractSourcePath<?>) other;

    return Objects.equals(this.asReference(), that.asReference());
  }

  @Override
  public String toString() {
    return String.valueOf(asReference());
  }
}

@@ -1663,24 +1663,75 @@
 ct other) %7B%0A
+    if (this == other) %7B%0A      return true;%0A    %7D%0A%0A
     if (othe

Add fast-path for AbstractSourcePath.equals