framework/src/main/java/org/checkerframework/framework/util/element/ElementAnnotationUtil.java

package org.checkerframework.framework.util.element;

import com.sun.tools.javac.code.Attribute;
import com.sun.tools.javac.code.Attribute.TypeCompound;
import com.sun.tools.javac.code.TargetType;
import com.sun.tools.javac.code.Type;
import com.sun.tools.javac.code.TypeAnnotationPosition;
import com.sun.tools.javac.code.TypeAnnotationPosition.TypePathEntry;
import com.sun.tools.javac.code.TypeAnnotationPosition.TypePathEntryKind;
import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Collection;
import java.util.HashMap;
import java.util.IdentityHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Set;
import javax.lang.model.element.AnnotationMirror;
import javax.lang.model.element.Element;
import javax.lang.model.type.TypeKind;
import javax.lang.model.type.TypeVariable;
import org.checkerframework.checker.formatter.qual.FormatMethod;
import org.checkerframework.framework.type.AnnotatedTypeFactory;
import org.checkerframework.framework.type.AnnotatedTypeMirror;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedArrayType;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedDeclaredType;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedIntersectionType;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedNullType;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedUnionType;
import org.checkerframework.framework.type.AnnotatedTypeMirror.AnnotatedWildcardType;
import org.checkerframework.framework.type.ElementAnnotationApplier;
import org.checkerframework.framework.util.AnnotatedTypes;
import org.checkerframework.javacutil.AnnotationUtils;
import org.checkerframework.javacutil.BugInCF;
import org.checkerframework.javacutil.TypesUtils;
import org.plumelib.util.StringsPlume;

/**
 * Utility methods for adding the annotations that are stored in an Element to the type that
 * represents that element (or a use of that Element). This class also contains package private
 * methods used by the ElementAnnotationAppliers that do most of the work.
 */
public class ElementAnnotationUtil {

  /**
   * For each type/element pair, add all of the annotations stored in Element to type. See apply for
   * more details.
   *
   * @param types the types to which we wish to apply element annotations
   * @param elements the elements that may contain annotations to apply. elements.size must ==
   *     types.size
   * @param typeFactory the type factory used to create the AnnotatedTypeMirrors contained by types
   */
  public static void applyAllElementAnnotations(
      final List<? extends AnnotatedTypeMirror> types,
      final List<? extends Element> elements,
      final AnnotatedTypeFactory typeFactory) {

    if (types.size() != elements.size()) {
      throw new BugInCF(
          "Number of types and elements don't match. "
              + "types ( "
              + StringsPlume.join(", ", types)
              + " ) "
              + "element ( "
              + StringsPlume.join(", ", elements)
              + " ) ");
    }

    for (int i = 0; i < types.size(); i++) {
      ElementAnnotationApplier.apply(types.get(i), elements.get(i), typeFactory);
    }
  }

  /**
   * When a declaration annotation is an alias for a type annotation, then the Checker Framework may
   * move the annotation before replacing it by the canonical version.
   *
   * <p>If the annotation is one of the Checker Framework compatibility annotations, for example
   * org.checkerframework.checker.nullness.compatqual.NonNullDecl, then it is interpreted as a type
   * annotation in the same location.
   *
   * @param type the type to annotate
   * @param annotations the annotations to add
   */
  @SuppressWarnings("interning:not.interned") // AST node comparison
  static void addDeclarationAnnotationsFromElement(
      final AnnotatedTypeMirror type, final List<? extends AnnotationMirror> annotations) {
    // The code here should be similar to
    // org.checkerframework.framework.type.TypeFromMemberVisitor.visitVariable
    AnnotatedTypeMirror innerType = AnnotatedTypes.innerMostType(type);
    if (innerType != type) {
      for (AnnotationMirror annotation : annotations) {
        if (AnnotationUtils.annotationName(annotation).startsWith("org.checkerframework")) {
          innerType.addAnnotation(annotation);
        } else {
          type.addAnnotation(annotation);
        }
      }
    } else {
      type.addAnnotations(annotations);
    }
  }

  /**
   * Does expectedValues contain enumValue. This is just a linear search.
   *
   * @param enumValue value to search for, a needle
   * @param expectedValues values to search through, a haystack
   * @return true if enumValue is in expectedValues, false otherwise
   */
  static boolean contains(Object enumValue, Object[] expectedValues) {
    for (final Object expected : expectedValues) {
      if (enumValue.equals(expected)) {
        return true;
      }
    }

    return false;
  }

  /**
   * Use a map to partition annotations with the given TargetTypes into Lists, where each target
   * type is a key in the output map. Any annotation that does not have one of these target types
   * will be added to unmatched
   *
   * @param annos the collection of annotations to partition
   * @param unmatched a list to add annotations with unmatched target types to
   * @param targetTypes a list of target types to partition annos with
   * @return a map from targetType &rarr; List of Annotations that have that targetType
   */
  static Map<TargetType, List<TypeCompound>> partitionByTargetType(
      Collection<TypeCompound> annos, List<TypeCompound> unmatched, TargetType... targetTypes) {
    final Map<TargetType, List<TypeCompound>> targetTypeToAnnos = new HashMap<>();
    for (TargetType targetType : targetTypes) {
      targetTypeToAnnos.put(targetType, new ArrayList<>());
    }

    for (final TypeCompound anno : annos) {
      final List<TypeCompound> annoSet = targetTypeToAnnos.get(anno.getPosition().type);
      if (annoSet != null) {
        annoSet.add(anno);
      } else if (unmatched != null) {
        unmatched.add(anno);
      }
    }

    return targetTypeToAnnos;
  }

  /**
   * A class used solely to annotate wildcards from Element annotations. Instances of
   * WildcardBoundAnnos are used to aggregate ALL annotations for a given Wildcard and then apply
   * them all at once in order to resolve the annotations in front of unbound wildcards.
   *
   * <p>Wildcard annotations are applied as follows:
   *
   * <ul>
   *   <li>a) If an Annotation is in front of a extends or super bounded wildcard, it applies to the
   *       bound that is NOT explicitly present. e.g.
   *       <pre>{@code
   * <@A ? extends Object> -- @A is placed on the super bound (Void)
   * <@B ? super CharSequence> -- @B is placed on the extends bound (probably Object)
   * }</pre>
   *   <li>b) If an Annotation is on a bound, it applies to that bound. E.g.
   *       <pre>{@code
   * <? extends @A Object> -- @A is placed on the extends bound (Object)
   * <? super @B CharSequence> -- @B is placed on the super bound (CharSequence)
   * }</pre>
   *   <li>c) If an Annotation is on an unbounded wildcard there are two subcases.
   *       <ul>
   *         <li>c.1 The user wrote the annotation explicitly -- these annotations apply to both
   *             bounds e.g. the user wrote
   *             <pre>{@code
   * <@C ?> -- the annotation is placed on the extends/super bounds
   * }</pre>
   *         <li>c.2 Previous calls to getAnnotatedType have annotated this wildcard with BOTH
   *             bounds e.g. the user wrote {@code <?>} but the checker framework added {@code <@C ?
   *             extends @D Object>} to the corresponding element.
   *             <pre>
   *             {@code <?> -- @C is placed on the lower bound and @D is placed on the upper bound
   *          This case is treated just like annotations in cases a/b.
   * }</pre>
   *       </ul>
   * </ul>
   */
  private static final class WildcardBoundAnnos {
    public final AnnotatedWildcardType wildcard;
    public final Set<AnnotationMirror> upperBoundAnnos;
    public final Set<AnnotationMirror> lowerBoundAnnos;

    // indicates that this is an annotation in front of an unbounded wildcard
    // e.g.  < @A ? >
    // For each annotation in this set, if there is no annotation in upperBoundAnnos
    // that is in the same hierarchy then the annotation will be applied to both bounds
    // otherwise the annotation applies to the lower bound only
    public final Set<AnnotationMirror> possiblyBoth;

    /** Whether or not wildcard has an explicit super bound. */
    private final boolean isSuperBounded;

    /** Whether or not wildcard has NO explicit bound whatsoever. */
    private final boolean isUnbounded;

    WildcardBoundAnnos(AnnotatedWildcardType wildcard) {
      this.wildcard = wildcard;
      this.upperBoundAnnos = AnnotationUtils.createAnnotationSet();
      this.lowerBoundAnnos = AnnotationUtils.createAnnotationSet();
      this.possiblyBoth = AnnotationUtils.createAnnotationSet();

      this.isSuperBounded = AnnotatedTypes.hasExplicitSuperBound(wildcard);
      this.isUnbounded = AnnotatedTypes.hasNoExplicitBound(wildcard);
    }

    void addAnnotation(final TypeCompound anno) {
      // if the typepath entry ends in Wildcard then the annotation should go on a bound
      // otherwise, the annotation is in front of the wildcard
      // e.g. @HERE ? extends Object
      final boolean isInFrontOfWildcard =
          anno.getPosition().location.last() != TypePathEntry.WILDCARD;
      if (isInFrontOfWildcard && isUnbounded) {
        possiblyBoth.add(anno);

      } else {
        // A TypePathEntry of WILDCARD indicates that it is placed on the bound
        // use the type of the wildcard bound to determine which set to put it in

        if (isInFrontOfWildcard) {
          if (isSuperBounded) {
            upperBoundAnnos.add(anno);
          } else {
            lowerBoundAnnos.add(anno);
          }
        } else { // it's on the bound
          if (isSuperBounded) {
            lowerBoundAnnos.add(anno);
          } else {
            upperBoundAnnos.add(anno);
          }
        }
      }
    }

    /**
     * Apply the annotations to wildcard according to the rules outlined in the comment at the
     * beginning of this class.
     */
    void apply() {
      final AnnotatedTypeMirror extendsBound = wildcard.getExtendsBound();
      final AnnotatedTypeMirror superBound = wildcard.getSuperBound();

      for (AnnotationMirror extAnno : upperBoundAnnos) {
        extendsBound.addAnnotation(extAnno);
      }
      for (AnnotationMirror supAnno : lowerBoundAnnos) {
        superBound.addAnnotation(supAnno);
      }

      for (AnnotationMirror anno : possiblyBoth) {
        superBound.addAnnotation(anno);

        // This will be false if we've defaulted the bounds and are reading them again.
        // In that case, we will have already created an annotation for the extends bound
        // that should be honored and NOT overwritten.
        if (!extendsBound.isAnnotatedInHierarchy(anno)) {
          extendsBound.addAnnotation(anno);
        }
      }
    }
  }

  /**
   * TypeCompounds are implementations of AnnotationMirror that are stored on Elements. Each type
   * compound has a TypeAnnotationPosition which identifies, relative to the "root" of a type, where
   * an annotation should be placed. This method adds all of the given TypeCompounds to the correct
   * location on type by interpreting the TypeAnnotationPosition.
   *
   * <p>Note: We handle all of the Element annotations on a type at once because we need to identify
   * whether or not the element annotation in front of an unbound wildcard (e.g. {@code <@HERE ?>})
   * should apply to only the super bound or both the super bound and the extends bound.
   *
   * @see org.checkerframework.framework.util.element.ElementAnnotationUtil.WildcardBoundAnnos
   * @param type the type in which annos should be placed
   * @param annos all of the element annotations, TypeCompounds, for type
   */
  static void annotateViaTypeAnnoPosition(
      final AnnotatedTypeMirror type, final Collection<TypeCompound> annos)
      throws UnexpectedAnnotationLocationException {
    final IdentityHashMap<AnnotatedWildcardType, WildcardBoundAnnos> wildcardToAnnos =
        new IdentityHashMap<>();
    for (final TypeCompound anno : annos) {
      AnnotatedTypeMirror target = getTypeAtLocation(type, anno.position.location, anno, false);
      if (target.getKind() == TypeKind.WILDCARD) {
        addWildcardToBoundMap((AnnotatedWildcardType) target, anno, wildcardToAnnos);
      } else {
        target.addAnnotation(anno);
      }
    }

    for (WildcardBoundAnnos wildcardAnnos : wildcardToAnnos.values()) {
      wildcardAnnos.apply();
    }
  }

  /**
   * Creates an entry in wildcardToAnnos for wildcard if one does not already exists. Adds anno to
   * the WildcardBoundAnnos object for wildcard.
   */
  private static void addWildcardToBoundMap(
      final AnnotatedWildcardType wildcard,
      final TypeCompound anno,
      final Map<AnnotatedWildcardType, WildcardBoundAnnos> wildcardToAnnos) {
    WildcardBoundAnnos boundAnnos =
        wildcardToAnnos.computeIfAbsent(wildcard, WildcardBoundAnnos::new);
    boundAnnos.addAnnotation(anno);
  }

  /**
   * Returns true if the typeCompound is a primary annotation for the type it targets (or lower
   * bound if this is a type variable or wildcard ). If you think of a type as a tree-like structure
   * then a nested type any type that is not the root. E.g. {@code @T List< @N String>}, @T is on a
   * top-level NON-nested type where as the annotation @N is on a nested type.
   *
   * @param typeCompound the type compound to inspect
   * @return true if typeCompound is placed on a nested type, false otherwise
   */
  static boolean isOnComponentType(final Attribute.TypeCompound typeCompound) {
    return !typeCompound.position.location.isEmpty();
  }

  /**
   * See the Type Annotation Specification on bounds
   * (https://checkerframework.org/jsr308/specification/java-annotation-design.html).
   *
   * <p>TypeAnnotationPositions have bound indices when they represent an upper bound on a
   * TypeVariable. The index 0 ALWAYS refers to the superclass type. If that supertype is implied to
   * be Object (because we didn't specify an extends) then the actual types will be offset by 1
   * (because index 0 is ALWAYS a class.
   *
   * <p>Therefore, These indices will be offset by -1 if the first type in the bound is an interface
   * which implies the specified type itself is an interface.
   *
   * <p>Reminder: There will only be multiple bound types if the upperBound is an intersection.
   *
   * @param upperBoundTypes the list of upperBounds for the type with bound positions you wish to
   *     offset
   * @return the bound offset for all TypeAnnotationPositions of TypeCompounds targeting these
   *     bounds
   */
  static int getBoundIndexOffset(final List<? extends AnnotatedTypeMirror> upperBoundTypes) {
    final int boundIndexOffset;
    if (((Type) upperBoundTypes.get(0).getUnderlyingType()).isInterface()) {
      boundIndexOffset = -1;
    } else {
      boundIndexOffset = 0;
    }

    return boundIndexOffset;
  }

  /**
   * Overload of getTypeAtLocation with default values null/false for the annotation and array
   * component flag, to make usage easier. Default visibility to allow usage within package.
   */
  static AnnotatedTypeMirror getTypeAtLocation(
      AnnotatedTypeMirror type, List<TypeAnnotationPosition.TypePathEntry> location)
      throws UnexpectedAnnotationLocationException {
    return getTypeAtLocation(type, location, null, false);
  }

  /**
   * Given a TypePath into a type, return the component type that is located at the end of the
   * TypePath.
   *
   * @param type a type containing the type specified by location
   * @param location a type path into type
   * @param anno an annotation to be applied to the inner types of a declared type if the declared
   *     type is itself a component type of an array
   * @param isComponentTypeOfArray indicates whether the type under analysis is a component type of
   *     some array type
   * @return the type specified by location
   */
  private static AnnotatedTypeMirror getTypeAtLocation(
      AnnotatedTypeMirror type,
      List<TypeAnnotationPosition.TypePathEntry> location,
      TypeCompound anno,
      boolean isComponentTypeOfArray)
      throws UnexpectedAnnotationLocationException {
    if (location.isEmpty() && type.getKind() != TypeKind.DECLARED) {
      // An annotation with an empty type path on a declared type applies to the outermost enclosing
      // type. This logic is handled together with non-empty type paths in getLocationTypeADT. For
      // other kinds of types, no work is required for an empty type path.
      return type;
    }
    switch (type.getKind()) {
      case NULL:
        return getLocationTypeANT((AnnotatedNullType) type, location);
      case DECLARED:
        return getLocationTypeADT(
            (AnnotatedDeclaredType) type, location, anno, isComponentTypeOfArray);
      case WILDCARD:
        return getLocationTypeAWT((AnnotatedWildcardType) type, location);
      case TYPEVAR:
        if (TypesUtils.isCaptured((TypeVariable) type.getUnderlyingType())) {
          // Work-around for Issue 1696: ignore captured wildcards.
          // There is no reason to observe such a type and it would be better
          // to prevent that this type ever reaches this point.
          return type;
        }
        // Raise an error for all other type variables (why isn't this needed?).
        break;
      case ARRAY:
        return getLocationTypeAAT((AnnotatedArrayType) type, location, anno);
      case UNION:
        return getLocationTypeAUT((AnnotatedUnionType) type, location);
      case INTERSECTION:
        return getLocationTypeAIT((AnnotatedIntersectionType) type, location);
      default:
        // Raise an error for all other types below.
    }
    throw new UnexpectedAnnotationLocationException(
        "ElementAnnotationUtil.getTypeAtLocation: "
            + "unexpected annotation with location found for type: %s (kind: %s ) location: ",
        type, type.getKind(), location);
  }

  /**
   * Given a TypePath into a declared type, return the component type that is located at the end of
   * the TypePath.
   *
   * @param type a type containing the type specified by location
   * @param location a type path into type
   * @param anno an annotation to be applied to the inner types of the declared type if the declared
   *     type is itself a component type of an array
   * @param isComponentTypeOfArray indicates whether the type under analysis is a component type of
   *     some array type
   * @return the type specified by location
   */
  @SuppressWarnings("JdkObsolete") // error is issued on every operation, must suppress here
  private static AnnotatedTypeMirror getLocationTypeADT(
      AnnotatedDeclaredType type,
      List<TypeAnnotationPosition.TypePathEntry> location,
      TypeCompound anno,
      boolean isComponentTypeOfArray)
      throws UnexpectedAnnotationLocationException {
    // List order by outermost type to innermost type.
    ArrayDeque<AnnotatedDeclaredType> outerToInner = new ArrayDeque<>();
    AnnotatedDeclaredType enclosing = type;
    while (enclosing != null) {
      outerToInner.addFirst(enclosing);
      enclosing = enclosing.getEnclosingType();
    }

    // If the AnnotatedDeclaredType is a component of an array type, then apply anno to all
    // possible inner types.
    // NOTE: This workaround can be removed once
    // https://bugs.openjdk.java.net/browse/JDK-8208470 is fixed
    // The number of enclosing types is outerToInner.size() - 1; there only is
    // work to do if outerToInner contains more than one element.
    if (anno != null && isComponentTypeOfArray && location.isEmpty() && outerToInner.size() > 1) {
      ArrayDeque<AnnotatedDeclaredType> innerTypes = new ArrayDeque<>(outerToInner);
      innerTypes.removeFirst();
      while (!innerTypes.isEmpty()) {
        innerTypes.removeFirst().addAnnotation(anno);
      }
    }

    // Create a linked list of the location, so removing the first element is easier.
    // Also, the tail() operation wouldn't work with a Deque.
    @SuppressWarnings("JdkObsolete")
    LinkedList<TypePathEntry> tailOfLocations = new LinkedList<>(location);
    boolean error = false;
    while (!tailOfLocations.isEmpty()) {
      TypePathEntry currentLocation = tailOfLocations.removeFirst();
      switch (currentLocation.tag) {
        case INNER_TYPE:
          outerToInner.removeFirst();
          break;
        case TYPE_ARGUMENT:
          AnnotatedDeclaredType innerType = outerToInner.getFirst();
          if (currentLocation.arg < innerType.getTypeArguments().size()) {
            AnnotatedTypeMirror typeArg = innerType.getTypeArguments().get(currentLocation.arg);
            return getTypeAtLocation(typeArg, tailOfLocations);
          } else {
            error = true;
            break;
          }
        default:
          error = true;
      }
      if (error) {
        break;
      }
    }

    if (outerToInner.isEmpty() || error) {
      throw new UnexpectedAnnotationLocationException(
          "ElementAnnotationUtil.getLocationTypeADT: invalid location %s for type: %s",
          location, type);
    }

    return outerToInner.getFirst();
  }

  private static AnnotatedTypeMirror getLocationTypeANT(
      AnnotatedNullType type, List<TypeAnnotationPosition.TypePathEntry> location)
      throws UnexpectedAnnotationLocationException {
    if (location.size() == 1 && location.get(0).tag == TypePathEntryKind.TYPE_ARGUMENT) {
      return type;
    }

    throw new UnexpectedAnnotationLocationException(
        "ElementAnnotationUtil.getLocationTypeANT: " + "invalid location %s for type: %s ",
        location, type);
  }

  private static AnnotatedTypeMirror getLocationTypeAWT(
      final AnnotatedWildcardType type, final List<TypeAnnotationPosition.TypePathEntry> location)
      throws UnexpectedAnnotationLocationException {

    // the last step into the Wildcard type is handled in WildcardToBoundAnnos.addAnnotation
    if (location.size() == 1) {
      return type;
    }

    if (!location.isEmpty()
        && location.get(0).tag == TypeAnnotationPosition.TypePathEntryKind.WILDCARD) {
      if (AnnotatedTypes.hasExplicitExtendsBound(type)) {
        return getTypeAtLocation(type.getExtendsBound(), tail(location));
      } else if (AnnotatedTypes.hasExplicitSuperBound(type)) {
        return getTypeAtLocation(type.getSuperBound(), tail(location));
      } else {
        return getTypeAtLocation(type.getExtendsBound(), tail(location));
      }

    } else {
      throw new UnexpectedAnnotationLocationException(
          "ElementAnnotationUtil.getLocationTypeAWT: " + "invalid location %s for type: %s ",
          location, type);
    }
  }

  /**
   * When we have an (e.g. @Odd int @NonNull []) the type-annotation position of the array
   * annotation (@NonNull) is really the outermost type in the TypeAnnotationPosition and it will
   * NOT have TypePathEntryKind.ARRAY at the end of its position. The position of the component type
   * (@Odd) is considered deeper in the type and therefore has the TypePathEntryKind.ARRAY in its
   * position.
   */
  private static AnnotatedTypeMirror getLocationTypeAAT(
      AnnotatedArrayType type,
      List<TypeAnnotationPosition.TypePathEntry> location,
      TypeCompound anno)
      throws UnexpectedAnnotationLocationException {
    if (location.size() >= 1
        && location.get(0).tag == TypeAnnotationPosition.TypePathEntryKind.ARRAY) {
      AnnotatedTypeMirror comptype = type.getComponentType();
      return getTypeAtLocation(comptype, tail(location), anno, true);
    } else {
      throw new UnexpectedAnnotationLocationException(
          "ElementAnnotationUtil.annotateAAT: " + "invalid location %s for type: %s ",
          location, type);
    }
  }

  /*
   * TODO: this case should never occur!
   * A union type can only occur in special locations, e.g. for exception
   * parameters. The EXCEPTION_PARAMETER TartetType should be used to
   * decide which of the alternatives in the union to annotate.
   * Only the TypePathEntry is not enough.
   * As a hack, always annotate the first alternative.
   */
  private static AnnotatedTypeMirror getLocationTypeAUT(
      AnnotatedUnionType type, List<TypeAnnotationPosition.TypePathEntry> location)
      throws UnexpectedAnnotationLocationException {
    AnnotatedTypeMirror comptype = type.getAlternatives().get(0);
    return getTypeAtLocation(comptype, location);
  }

  /** Intersection types use the TYPE_ARGUMENT index to separate the individual types. */
  private static AnnotatedTypeMirror getLocationTypeAIT(
      AnnotatedIntersectionType type, List<TypeAnnotationPosition.TypePathEntry> location)
      throws UnexpectedAnnotationLocationException {
    if (location.size() >= 1
        && location.get(0).tag == TypeAnnotationPosition.TypePathEntryKind.TYPE_ARGUMENT) {
      AnnotatedTypeMirror bound = type.getBounds().get(location.get(0).arg);
      return getTypeAtLocation(bound, tail(location));
    } else {
      throw new UnexpectedAnnotationLocationException(
          "ElementAnnotationUtil.getLocatonTypeAIT: invalid location %s for type: %s ",
          location, type);
    }
  }

  private static <T> List<T> tail(List<T> list) {
    return list.subList(1, list.size());
  }

  /** Exception indicating an invalid location for an annotation was found. */
  @SuppressWarnings("serial")
  public static class UnexpectedAnnotationLocationException extends Exception {

    /**
     * Creates an UnexpectedAnnotationLocationException.
     *
     * @param format format string
     * @param args arguments to the format string
     */
    @FormatMethod
    private UnexpectedAnnotationLocationException(String format, Object... args) {
      super(String.format(format, args));
    }
  }

  /** An ERROR TypeKind was found. */
  @SuppressWarnings("serial")
  public static class ErrorTypeKindException extends Error {

    /**
     * Creates an ErrorTypeKindException.
     *
     * @param format format string
     * @param args arguments to the format string
     */
    @FormatMethod
    public ErrorTypeKindException(String format, Object... args) {
      super(String.format(format, args));
    }
  }
}