gt:                     return new Error(prefix, code, args);
context: /*
   * Copyright (c) 2003, 2015, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.  Oracle designates this
   * particular file as subject to the "Classpath" exception as provided
   * by Oracle in the LICENSE file that accompanied this code.
   *
   * This code is distributed in the hope that it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
   * version 2 for more details (a copy is included in the LICENSE file that
   * accompanied this code).
   *
   * You should have received a copy of the GNU General Public License version
   * 2 along with this work; if not, write to the Free Software Foundation,
   * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  
  package com.sun.tools.javac.util;
  
  import java.util.EnumSet;
  import java.util.Locale;
  import java.util.Set;
  import java.util.stream.Stream;
  
  import javax.tools.Diagnostic;
  import javax.tools.JavaFileObject;
  
  import com.sun.tools.javac.api.DiagnosticFormatter;
  import com.sun.tools.javac.code.Lint.LintCategory;
  import com.sun.tools.javac.tree.EndPosTable;
  import com.sun.tools.javac.tree.JCTree;
  import com.sun.tools.javac.util.DefinedBy.Api;
  
  import static com.sun.tools.javac.util.JCDiagnostic.DiagnosticType.*;
  
  /** An abstraction of a diagnostic message generated by the compiler.
   *
   *  <p><b>This is NOT part of any supported API.
   *  If you write code that depends on this, you do so at your own risk.
   *  This code and its internal interfaces are subject to change or
   *  deletion without notice.</b>
   */
  public class JCDiagnostic implements Diagnostic<JavaFileObject> {
      /** A factory for creating diagnostic objects. */
      public static class Factory {
          /** The context key for the diagnostic factory. */
          protected static final Context.Key<JCDiagnostic.Factory> diagnosticFactoryKey = new Context.Key<>();
  
          /** Get the Factory instance for this context. */
          public static Factory instance(Context context) {
              Factory instance = context.get(diagnosticFactoryKey);
              if (instance == null)
                  instance = new Factory(context);
              return instance;
          }
  
          DiagnosticFormatter<JCDiagnostic> formatter;
          final String prefix;
          final Set<DiagnosticFlag> defaultErrorFlags;
  
          /** Create a new diagnostic factory. */
          protected Factory(Context context) {
              this(JavacMessages.instance(context), "compiler");
              context.put(diagnosticFactoryKey, this);
  
              final Options options = Options.instance(context);
              initOptions(options);
              options.addListener(() -> initOptions(options));
          }
  
          private void initOptions(Options options) {
              if (options.isSet("onlySyntaxErrorsUnrecoverable"))
                  defaultErrorFlags.add(DiagnosticFlag.RECOVERABLE);
          }
  
          /** Create a new diagnostic factory. */
          public Factory(JavacMessages messages, String prefix) {
              this.prefix = prefix;
              this.formatter = new BasicDiagnosticFormatter(messages);
              defaultErrorFlags = EnumSet.of(DiagnosticFlag.MANDATORY);
          }
  
          /**
           * Create an error diagnostic
           *  @param source The source of the compilation unit, if any, in which to report the error.
           *  @param pos    The source position at which to report the error.
           *  @param key    The key for the localized error message.
           *  @param args   Fields of the error message.
           */
          public JCDiagnostic error(
                  DiagnosticFlag flag, DiagnosticSource source, DiagnosticPosition pos, String key, Object... args) {
              return error(flag, source, pos, errorKey(key, args));
          }
  
          /**
           * Create an error diagnostic
           *  @param source The source of the compilation unit, if any, in which to report the error.
           *  @param pos    The source position at which to report the error.
           *  @param errorKey    The key for the localized error message.
           */
          public JCDiagnostic error(
                  DiagnosticFlag flag, DiagnosticSource source, DiagnosticPosition pos, Error errorKey) {
              JCDiagnostic diag = create(null, EnumSet.copyOf(defaultErrorFlags), source, pos, errorKey);
              if (flag != null) {
                  diag.setFlag(flag);
              }
              return diag;
          }
  
          /**
           * Create a warning diagnostic that will not be hidden by the -nowarn or -Xlint:none options.
           *  @param lc     The lint category for the diagnostic
           *  @param source The source of the compilation unit, if any, in which to report the warning.
           *  @param pos    The source position at which to report the warning.
           *  @param key    The key for the localized warning message.
           *  @param args   Fields of the warning message.
           *  @see MandatoryWarningHandler
           */
          public JCDiagnostic mandatoryWarning(
                  LintCategory lc,
                  DiagnosticSource source, DiagnosticPosition pos, String key, Object... args) {
              return mandatoryWarning(lc, source, pos, warningKey(key, args));
          }
  
          /**
           * Create a warning diagnostic that will not be hidden by the -nowarn or -Xlint:none options.
           *  @param lc     The lint category for the diagnostic
           *  @param source The source of the compilation unit, if any, in which to report the warning.
           *  @param pos    The source position at which to report the warning.
           *  @param warningKey    The key for the localized warning message.
           *  @see MandatoryWarningHandler
           */
          public JCDiagnostic mandatoryWarning(
                  LintCategory lc,
                  DiagnosticSource source, DiagnosticPosition pos, Warning warningKey) {
              return create(lc, EnumSet.of(DiagnosticFlag.MANDATORY), source, pos, warningKey);
          }
  
          /**
           * Create a warning diagnostic.
           *  @param lc     The lint category for the diagnostic
           *  @param source The source of the compilation unit, if any, in which to report the warning.
           *  @param pos    The source position at which to report the warning.
           *  @param key    The key for the localized error message.
           *  @param args   Fields of the warning message.
           *  @see MandatoryWarningHandler
           */
          public JCDiagnostic warning(
                  LintCategory lc, DiagnosticSource source, DiagnosticPosition pos, String key, Object... args) {
              return warning(lc, source, pos, warningKey(key, args));
          }
  
          /**
           * Create a warning diagnostic.
           *  @param lc     The lint category for the diagnostic
           *  @param source The source of the compilation unit, if any, in which to report the warning.
           *  @param pos    The source position at which to report the warning.
           *  @param warningKey    The key for the localized warning message.
           *  @see MandatoryWarningHandler
           */
          public JCDiagnostic warning(
                  LintCategory lc, DiagnosticSource source, DiagnosticPosition pos, Warning warningKey) {
              return create(lc, EnumSet.noneOf(DiagnosticFlag.class), source, pos, warningKey);
          }
  
          /**
           * Create a note diagnostic that will not be hidden by the -nowarn or -Xlint:none options.
           *  @param source The source of the compilation unit, if any, in which to report the warning.
           *  @param key    The key for the localized warning message.
           *  @param args   Fields of the warning message.
           *  @see MandatoryWarningHandler
           */
          public JCDiagnostic mandatoryNote(DiagnosticSource source, String key, Object... args) {
              return mandatoryNote(source, noteKey(key, args));
          }
  
          /**
           * Create a note diagnostic that will not be hidden by the -nowarn or -Xlint:none options.
           *  @param noteKey    The key for the localized note message.
           *  @see MandatoryWarningHandler
           */
          public JCDiagnostic mandatoryNote(DiagnosticSource source, Note noteKey) {
              return create(null, EnumSet.of(DiagnosticFlag.MANDATORY), source, null, noteKey);
          }
  
          /**
           * Create a note diagnostic.
           *  @param key    The key for the localized error message.
           *  @param args   Fields of the message.
           */
          public JCDiagnostic note(
                  DiagnosticSource source, DiagnosticPosition pos, String key, Object... args) {
              return note(source, pos, noteKey(key, args));
          }
  
          /**
           * Create a note diagnostic.
           *  @param source The source of the compilation unit, if any, in which to report the note.
           *  @param pos    The source position at which to report the note.
           *  @param noteKey    The key for the localized note message.
           */
          public JCDiagnostic note(
                  DiagnosticSource source, DiagnosticPosition pos, Note noteKey) {
              return create(null, EnumSet.noneOf(DiagnosticFlag.class), source, pos, noteKey);
          }
  
          /**
           * Create a fragment diagnostic, for use as an argument in other diagnostics
           *  @param key    The key for the localized message.
           *  @param args   Fields of the message.
           */
          public JCDiagnostic fragment(String key, Object... args) {
              return fragment(fragmentKey(key, args));
          }
  
          /**
           * Create a fragment diagnostic, for use as an argument in other diagnostics
           *  @param fragmentKey    The key for the localized subdiagnostic message.
           */
          public JCDiagnostic fragment(Fragment fragmentKey) {
              return create(null, EnumSet.noneOf(DiagnosticFlag.class), null, null, fragmentKey);
          }
  
          /**
           * Create a new diagnostic of the given kind, which is not mandatory and which has
           * no lint category.
           *  @param kind        The diagnostic kind
           *  @param source      The source of the compilation unit, if any, in which to report the message.
           *  @param pos         The source position at which to report the message.
           *  @param key         The key for the localized message.
           *  @param args        Fields of the message.
           */
          public JCDiagnostic create(
                  DiagnosticType kind, DiagnosticSource source, DiagnosticPosition pos, String key, Object... args) {
              return create(null, EnumSet.noneOf(DiagnosticFlag.class), source, pos, DiagnosticInfo.of(kind, prefix, key, args));
          }
  
          /**
           * Create a new diagnostic of the given kind, which is not mandatory and which has
           * no lint category.
           *  @param source      The source of the compilation unit, if any, in which to report the message.
           *  @param pos         The source position at which to report the message.
           *  @param diagnosticInfo         The key for the localized message.
           */
          public JCDiagnostic create(
                  DiagnosticSource source, DiagnosticPosition pos, DiagnosticInfo diagnosticInfo) {
              return create(null, EnumSet.noneOf(DiagnosticFlag.class), source, pos, diagnosticInfo);
          }
  
          /**
           * Create a new diagnostic of the given kind.
           *  @param kind        The diagnostic kind
           *  @param lc          The lint category, if applicable, or null
           *  @param flags       The set of flags for the diagnostic
           *  @param source      The source of the compilation unit, if any, in which to report the message.
           *  @param pos         The source position at which to report the message.
           *  @param key         The key for the localized message.
           *  @param args        Fields of the message.
           */
          public JCDiagnostic create(DiagnosticType kind,
                  LintCategory lc, Set<DiagnosticFlag> flags, DiagnosticSource source, DiagnosticPosition pos, String key, Object... args) {
              return create(lc, flags, source, pos, DiagnosticInfo.of(kind, prefix, key, args));
          }
  
          /**
           * Create a new diagnostic with given key.
           *  @param lc          The lint category, if applicable, or null
           *  @param flags       The set of flags for the diagnostic
           *  @param source      The source of the compilation unit, if any, in which to report the message.
           *  @param pos         The source position at which to report the message.
           *  @param diagnosticInfo    The key for the localized message.
           */
          public JCDiagnostic create(
                  LintCategory lc, Set<DiagnosticFlag> flags, DiagnosticSource source, DiagnosticPosition pos, DiagnosticInfo diagnosticInfo) {
              return new JCDiagnostic(formatter, normalize(diagnosticInfo), lc, flags, source, pos);
          }
          //where
              DiagnosticInfo normalize(DiagnosticInfo diagnosticInfo) {
                  //replace all nested FragmentKey with full-blown JCDiagnostic objects
                  return DiagnosticInfo.of(diagnosticInfo.type, diagnosticInfo.prefix, diagnosticInfo.code,
                          Stream.of(diagnosticInfo.args).map(o -> {
                              return (o instanceof Fragment) ?
                                      fragment((Fragment)o) : o;
                          }).toArray());
              }
  
          /**
           * Create a new error key.
           */
          Error errorKey(String code, Object... args) {
              return (Error)DiagnosticInfo.of(ERROR, prefix, code, args);
          }
  
          /**
           * Create a new warning key.
           */
          Warning warningKey(String code, Object... args) {
              return (Warning)DiagnosticInfo.of(WARNING, prefix, code, args);
          }
  
          /**
           * Create a new note key.
           */
          Note noteKey(String code, Object... args) {
              return (Note)DiagnosticInfo.of(NOTE, prefix, code, args);
          }
  
          /**
           * Create a new fragment key.
           */
          Fragment fragmentKey(String code, Object... args) {
              return (Fragment)DiagnosticInfo.of(FRAGMENT, prefix, code, args);
          }
      }
  
  
  
      /**
       * Create a fragment diagnostic, for use as an argument in other diagnostics
       *  @param key    The key for the localized error message.
       *  @param args   Fields of the error message.
       *
       */
      @Deprecated
      public static JCDiagnostic fragment(String key, Object... args) {
          return new JCDiagnostic(getFragmentFormatter(),
                                DiagnosticInfo.of(FRAGMENT,
                                        "compiler",
                                        key,
                                        args),
                                null,
                                EnumSet.noneOf(DiagnosticFlag.class),
                                null,
                                null);
      }
      //where
      @Deprecated
      public static DiagnosticFormatter<JCDiagnostic> getFragmentFormatter() {
          if (fragmentFormatter == null) {
              fragmentFormatter = new BasicDiagnosticFormatter(JavacMessages.getDefaultMessages());
          }
          return fragmentFormatter;
      }
  
      /**
       * A DiagnosticType defines the type of the diagnostic.
       **/
      public enum DiagnosticType {
          /** A fragment of an enclosing diagnostic. */
          FRAGMENT("misc"),
          /** A note: similar to, but less serious than, a warning. */
          NOTE("note"),
          /** A warning. */
          WARNING("warn"),
          /** An error. */
          ERROR("err");
  
          final String key;
  
          /** Create a DiagnosticType.
           * @param key A string used to create the resource key for the diagnostic.
           */
          DiagnosticType(String key) {
              this.key = key;
          }
      }
  
      /**
       * A DiagnosticPosition provides information about the positions in a file
       * that gave rise to a diagnostic. It always defines a "preferred" position
       * that most accurately defines the location of the diagnostic, it may also
       * provide a related tree node that spans that location.
       */
      public static interface DiagnosticPosition {
          /** Gets the tree node, if any, to which the diagnostic applies. */
          JCTree getTree();
          /** If there is a tree node, get the start position of the tree node.
           *  Otherwise, just returns the same as getPreferredPosition(). */
          int getStartPosition();
          /** Get the position within the file that most accurately defines the
           *  location for the diagnostic. */
          int getPreferredPosition();
          /** If there is a tree node, and if endPositions are available, get
           *  the end position of the tree node. Otherwise, just returns the
           *  same as getPreferredPosition(). */
          int getEndPosition(EndPosTable endPosTable);
      }
  
      /**
       * A DiagnosticPosition that simply identifies a position, but no related
       * tree node, as the location for a diagnostic. Used for scanner and parser
       * diagnostics. */
      public static class SimpleDiagnosticPosition implements DiagnosticPosition {
          public SimpleDiagnosticPosition(int pos) {
              this.pos = pos;
          }
  
          public JCTree getTree() {
              return null;
          }
  
          public int getStartPosition() {
              return pos;
          }
  
          public int getPreferredPosition() {
              return pos;
          }
  
          public int getEndPosition(EndPosTable endPosTable) {
              return pos;
          }
  
          private final int pos;
      }
  
      public enum DiagnosticFlag {
          MANDATORY,
          RESOLVE_ERROR,
          SYNTAX,
          RECOVERABLE,
          NON_DEFERRABLE,
          COMPRESSED,
          /** Print multiple errors for same source locations.
           */
          MULTIPLE,
          /** Flag for not-supported-in-source-X errors.
           */
          SOURCE_LEVEL;
      }
  
      private final DiagnosticSource source;
      private final DiagnosticPosition position;
      private final DiagnosticInfo diagnosticInfo;
      private final Set<DiagnosticFlag> flags;
      private final LintCategory lintCategory;
  
      /** source line position (set lazily) */
      private SourcePosition sourcePosition;
  
      /**
       * This class is used to defer the line/column position fetch logic after diagnostic construction.
       */
      class SourcePosition {
  
          private final int line;
          private final int column;
  
          SourcePosition() {
              int n = (position == null ? Position.NOPOS : position.getPreferredPosition());
              if (n == Position.NOPOS || source == null)
                  line = column = -1;
              else {
                  line = source.getLineNumber(n);
                  column = source.getColumnNumber(n, true);
              }
          }
  
          public int getLineNumber() {
              return line;
          }
  
          public int getColumnNumber() {
              return column;
          }
      }
  
      /**
       * A diagnostic key object encapsulates basic properties of a diagnostic, such as the resource key,
       * the arguments and the kind associated with the diagnostic object. Diagnostic keys can be either
       * created programmatically (by using the supplied factory method) or obtained through build-time
       * generated factory methods.
       */
      public static abstract class DiagnosticInfo {
  
          /** The diagnostic kind (i.e. error). */
          DiagnosticType type;
  
          /** The diagnostic prefix (i.e. 'javac'); used to compute full resource key. */
          String prefix;
  
          /** The diagnostic code (i.e. 'cannot.resolve.sym'); together with {@code prefix} it forms
           * the full resource key. */
          String code;
  
          /** The diagnostic arguments. */
          Object[] args;
  
          private DiagnosticInfo(DiagnosticType type, String prefix, String code, Object... args) {
              this.type = type;
              this.prefix = prefix;
              this.code = code;
              this.args = args;
          }
  
          /**
           * Compute the resource key.
           */
          public String key() {
              return prefix + "." + type.key + "." + code;
          }
  
          /**
           * Static factory method; build a custom diagnostic key using given kind, prefix, code and args.
           */
          public static DiagnosticInfo of(DiagnosticType type, String prefix, String code, Object... args) {
              switch (type) {
                  case ERROR:
  