Extract DiagnosticReporter implementation from Compiler.

pkg/compiler/lib/src/compiler.dart

Index: pkg/compiler/lib/src/compiler.dart
diff --git a/pkg/compiler/lib/src/compiler.dart b/pkg/compiler/lib/src/compiler.dart
index 6ebb7a56ba782611176b0a4fd6e79451fc10195c..5df0af3c5812b6ca112e299d66a14df9155beb58 100644
--- a/pkg/compiler/lib/src/compiler.dart
+++ b/pkg/compiler/lib/src/compiler.dart
@@ -44,7 +44,10 @@ import 'dart_types.dart' show
     Types;
 import 'deferred_load.dart' show DeferredLoadTask, OutputUnit;
 import 'diagnostics/code_location.dart';
-import 'diagnostics/diagnostic_listener.dart';
+import 'diagnostics/diagnostic_listener.dart' show
+    DiagnosticMessage,
+    DiagnosticOptions,
+    DiagnosticReporter;
 import 'diagnostics/invariant.dart' show
     invariant,
     REPORT_EXCESS_RESOLUTION;
@@ -139,13 +142,14 @@ import 'util/util.dart' show
 import 'world.dart' show
     World;
 
-abstract class Compiler extends DiagnosticListener {
+abstract class Compiler {
 
   final Stopwatch totalCompileTime = new Stopwatch();
   int nextFreeClassId = 0;
   World world;
   Types types;
   _CompilerCoreTypes _coreTypes;
+  _CompilerDiagnosticReporter _reporter;
   _CompilerResolution _resolution;
   _CompilerParsing _parsing;
 
@@ -248,14 +252,6 @@ abstract class Compiler extends DiagnosticListener {
   /// If `true`, warnings and hints not from user code are reported.
   final bool showPackageWarnings;
 
-  /// `true` if the last diagnostic was filtered, in which case the
-  /// accompanying info message should be filtered as well.
-  bool lastDiagnosticWasFiltered = false;
-
-  /// Map containing information about the warnings and hints that have been
-  /// suppressed for each library.
-  Map<Uri, SuppressionInfo> suppressedWarnings = <Uri, SuppressionInfo>{};
-
   final bool suppressWarnings;
   final bool fatalWarnings;
 
@@ -287,7 +283,6 @@ abstract class Compiler extends DiagnosticListener {
   Tracer tracer;
 
   CompilerTask measuredTask;
-  Element _currentElement;
   LibraryElement coreLibrary;
   LibraryElement asyncLibrary;
 
@@ -318,6 +313,7 @@ abstract class Compiler extends DiagnosticListener {
   ClassElement get iterableClass => _coreTypes.iterableClass;
   ClassElement get streamClass => _coreTypes.streamClass;
 
+  DiagnosticReporter get reporter => _reporter;
   CoreTypes get coreTypes => _coreTypes;
   Resolution get resolution => _resolution;
   Parsing get parsing => _parsing;
@@ -378,49 +374,7 @@ abstract class Compiler extends DiagnosticListener {
 
   fromEnvironment(String name) => null;
 
-  Element get currentElement => _currentElement;
-
-  String tryToString(object) {
-    try {
-      return object.toString();
-    } catch (_) {
-      return '<exception in toString()>';
-    }
-  }
-
-  /**
-   * Perform an operation, [f], returning the return value from [f].  If an
-   * error occurs then report it as having occurred during compilation of
-   * [element].  Can be nested.
-   */
-  withCurrentElement(Element element, f()) {
-    Element old = currentElement;
-    _currentElement = element;
-    try {
-      return f();
-    } on SpannableAssertionFailure catch (ex) {
-      if (!hasCrashed) {
-        reportAssertionFailure(ex);
-        pleaseReportCrash();
-      }
-      hasCrashed = true;
-      rethrow;
-    } on StackOverflowError {
-      // We cannot report anything useful in this case, because we
-      // do not have enough stack space.
-      rethrow;
-    } catch (ex) {
-      if (hasCrashed) rethrow;
-      try {
-        unhandledExceptionOnElement(element);
-      } catch (doubleFault) {
-        // Ignoring exceptions in exception handling.
-      }
-      rethrow;
-    } finally {
-      _currentElement = old;
-    }
-  }
+  Element get currentElement => _reporter.currentElement;
 
   List<CompilerTask> tasks;
   ScannerTask scanner;
@@ -464,6 +418,8 @@ abstract class Compiler extends DiagnosticListener {
   bool enabledInvokeOn = false;
   bool hasIsolateSupport = false;
 
+  bool get hasCrashed => _reporter.hasCrashed;
+
   Stopwatch progress;
 
   bool get shouldPrintProgress {
@@ -487,8 +443,6 @@ abstract class Compiler extends DiagnosticListener {
     compilationFailedInternal = value;
   }
 
-  bool hasCrashed = false;
-
   /// Set by the backend if real reflection is detected in use of dart:mirrors.
   bool disableTypeInferenceForMirrors = false;
 
@@ -549,6 +503,11 @@ abstract class Compiler extends DiagnosticListener {
     world = new World(this);
     // TODO(johnniwinther): Initialize core types in [initializeCoreClasses] and
     // make its field final.
+    _reporter = new _CompilerDiagnosticReporter(this,
+        new DiagnosticOptions(
+            suppressWarnings: suppressWarnings,
+            terseDiagnostics: terseDiagnostics,
+            showPackageWarnings: showPackageWarnings));
     _parsing = new _CompilerParsing(this);
     _resolution = new _CompilerResolution(this);
     _coreTypes = new _CompilerCoreTypes(_resolution);
@@ -616,118 +575,15 @@ abstract class Compiler extends DiagnosticListener {
   int getNextFreeClassId() => nextFreeClassId++;
 
   void unimplemented(Spannable spannable, String methodName) {
-    internalError(spannable, "$methodName not implemented.");
-  }
-
-  internalError(Spannable node, reason) {
-    String message = tryToString(reason);
-    reportDiagnosticInternal(
-        createMessage(node, MessageKind.GENERIC, {'text': message}),
-        const <DiagnosticMessage>[],
-        api.Diagnostic.CRASH);
-    throw 'Internal Error: $message';
-  }
-
-  void unhandledExceptionOnElement(Element element) {
-    if (hasCrashed) return;
-    hasCrashed = true;
-    reportDiagnostic(
-        createMessage(element, MessageKind.COMPILER_CRASHED),
-        const <DiagnosticMessage>[],
-        api.Diagnostic.CRASH);
-    pleaseReportCrash();
-  }
-
-  void pleaseReportCrash() {
-    print(
-        MessageTemplate.TEMPLATES[MessageKind.PLEASE_REPORT_THE_CRASH]
-            .message({'buildId': buildId}));
-  }
-
-  SourceSpan spanFromSpannable(Spannable node) {
-    // TODO(johnniwinther): Disallow `node == null` ?
-    if (node == null) return null;
-    if (node == CURRENT_ELEMENT_SPANNABLE) {
-      node = currentElement;
-    } else if (node == NO_LOCATION_SPANNABLE) {
-      if (currentElement == null) return null;
-      node = currentElement;
-    }
-    if (node is SourceSpan) {
-      return node;
-    } else if (node is Node) {
-      return spanFromNode(node);
-    } else if (node is TokenPair) {
-      return spanFromTokens(node.begin, node.end);
-    } else if (node is Token) {
-      return spanFromTokens(node, node);
-    } else if (node is HInstruction) {
-      return spanFromHInstruction(node);
-    } else if (node is Element) {
-      return spanFromElement(node);
-    } else if (node is MetadataAnnotation) {
-      Uri uri = node.annotatedElement.compilationUnit.script.resourceUri;
-      return spanFromTokens(node.beginToken, node.endToken, uri);
-    } else if (node is Local) {
-      Local local = node;
-      return spanFromElement(local.executableContext);
-    } else {
-      throw 'No error location.';
-    }
-  }
-
-  Element _elementFromHInstruction(HInstruction instruction) {
-    return instruction.sourceElement is Element
-        ? instruction.sourceElement : null;
-  }
-
-  /// Finds the approximate [Element] for [node]. [currentElement] is used as
-  /// the default value.
-  Element elementFromSpannable(Spannable node) {
-    Element element;
-    if (node is Element) {
-      element = node;
-    } else if (node is HInstruction) {
-      element = _elementFromHInstruction(node);
-    } else if (node is MetadataAnnotation) {
-      element = node.annotatedElement;
-    }
-    return element != null ? element : currentElement;
-  }
-
-  void log(message) {
-    Message msg = MessageTemplate.TEMPLATES[MessageKind.GENERIC]
-        .message({'text': '$message'});
-    reportDiagnostic(
-        new DiagnosticMessage(null, null, msg),
-        const <DiagnosticMessage>[],
-        api.Diagnostic.VERBOSE_INFO);
+    reporter.internalError(spannable, "$methodName not implemented.");
   }
 
   Future<bool> run(Uri uri) {
     totalCompileTime.start();
 
-    return new Future.sync(() => runCompiler(uri)).catchError((error) {
-      try {
-        if (!hasCrashed) {
-          hasCrashed = true;
-          if (error is SpannableAssertionFailure) {
-            reportAssertionFailure(error);
-          } else {
-            reportDiagnostic(
-                createMessage(
-                    new SourceSpan(uri, 0, 0),
-                    MessageKind.COMPILER_CRASHED),
-                const <DiagnosticMessage>[],
-                api.Diagnostic.CRASH);
-          }
-          pleaseReportCrash();
-        }
-      } catch (doubleFault) {
-        // Ignoring exceptions in exception handling.
-      }
-      throw error;
-    }).whenComplete(() {
+    return new Future.sync(() => runCompiler(uri))
+        .catchError((error) => _reporter.onError(uri, error))
+        .whenComplete(() {
       tracer.close();
       totalCompileTime.stop();
     }).then((_) {
@@ -866,7 +722,7 @@ abstract class Compiler extends DiagnosticListener {
         if (loadedLibraries.containsLibrary(uri)) {
           Set<String> importChains =
               computeImportChainsFor(loadedLibraries, Uri.parse('dart:io'));
-          reportInfo(NO_LOCATION_SPANNABLE,
+          reporter.reportInfo(NO_LOCATION_SPANNABLE,
              MessageKind.DISALLOWED_LIBRARY_IMPORT,
               {'uri': uri,
                'importChain': importChains.join(
@@ -883,7 +739,7 @@ abstract class Compiler extends DiagnosticListener {
       if (importsMirrorsLibrary && !backend.supportsReflection) {
         Set<String> importChains =
             computeImportChainsFor(loadedLibraries, Uris.dart_mirrors);
-        reportErrorMessage(
+        reporter.reportErrorMessage(
             NO_LOCATION_SPANNABLE,
             MessageKind.MIRRORS_LIBRARY_NOT_SUPPORT_BY_BACKEND,
             {'importChain': importChains.join(
@@ -891,7 +747,7 @@ abstract class Compiler extends DiagnosticListener {
       } else if (importsMirrorsLibrary && !enableExperimentalMirrors) {
         Set<String> importChains =
             computeImportChainsFor(loadedLibraries, Uris.dart_mirrors);
-        reportWarningMessage(
+        reporter.reportWarningMessage(
             NO_LOCATION_SPANNABLE,
             MessageKind.IMPORT_EXPERIMENTAL_MIRRORS,
             {'importChain': importChains.join(
@@ -925,10 +781,10 @@ abstract class Compiler extends DiagnosticListener {
   Element findRequiredElement(LibraryElement library, String name) {
     var element = library.find(name);
     if (element == null) {
-      internalError(library,
+      reporter.internalError(library,
           "The library '${library.canonicalUri}' does not contain required "
           "element: '$name'.");
-      }
+    }
     return element;
   }
 
@@ -983,7 +839,7 @@ abstract class Compiler extends DiagnosticListener {
     _coreTypes.iterableClass = lookupCoreClass('Iterable');
     _coreTypes.symbolClass = lookupCoreClass('Symbol');
     if (!missingCoreClasses.isEmpty) {
-      internalError(
+      reporter.internalError(
           coreLibrary,
           'dart:core library does not contain required classes: '
           '$missingCoreClasses');
@@ -1020,16 +876,16 @@ abstract class Compiler extends DiagnosticListener {
     return new Future.sync(() {
       if (librariesToAnalyzeWhenRun != null) {
         return Future.forEach(librariesToAnalyzeWhenRun, (libraryUri) {
-          log('Analyzing $libraryUri ($buildId)');
+          reporter.log('Analyzing $libraryUri ($buildId)');
           return libraryLoader.loadLibrary(libraryUri);
         });
       }
     }).then((_) {
       if (uri != null) {
         if (analyzeOnly) {
-          log('Analyzing $uri ($buildId)');
+          reporter.log('Analyzing $uri ($buildId)');
         } else {
-          log('Compiling $uri ($buildId)');
+          reporter.log('Compiling $uri ($buildId)');
         }
         return libraryLoader.loadLibrary(uri).then((LibraryElement library) {
           mainApp = library;
@@ -1063,7 +919,7 @@ abstract class Compiler extends DiagnosticListener {
       if (main is ErroneousElement) {
         errorElement = main;
       } else {
-        internalError(main, 'Problem with ${Identifiers.main}.');
+        reporter.internalError(main, 'Problem with ${Identifiers.main}.');
       }
       mainFunction = backend.helperForBadMain();
     } else if (!main.isFunction) {
@@ -1091,7 +947,7 @@ abstract class Compiler extends DiagnosticListener {
     }
     if (mainFunction == null) {
       if (errorElement == null && !analyzeOnly && !analyzeAll) {
-        internalError(mainApp, "Problem with '${Identifiers.main}'.");
+        reporter.internalError(mainApp, "Problem with '${Identifiers.main}'.");
       } else {
         mainFunction = errorElement;
       }
@@ -1099,7 +955,7 @@ abstract class Compiler extends DiagnosticListener {
     if (errorElement != null &&
         errorElement.isSynthesized &&
         !mainApp.isSynthesized) {
-      reportWarningMessage(
+      reporter.reportWarningMessage(
           errorElement, errorElement.messageKind,
           errorElement.messageArguments);
     }
@@ -1116,7 +972,7 @@ abstract class Compiler extends DiagnosticListener {
       Uri libraryUri,
       {bool skipLibraryWithPartOfTag: true}) {
     assert(analyzeMain);
-    log('Analyzing $libraryUri ($buildId)');
+    reporter.log('Analyzing $libraryUri ($buildId)');
     return libraryLoader.loadLibrary(libraryUri).then((LibraryElement library) {
       var compilationUnit = library.compilationUnit;
       if (skipLibraryWithPartOfTag && compilationUnit.partTag != null) {
@@ -1124,7 +980,7 @@ abstract class Compiler extends DiagnosticListener {
       }
       fullyEnqueueLibrary(library, enqueuer.resolution);
       emptyQueue(enqueuer.resolution);
-      enqueuer.resolution.logSummary(log);
+      enqueuer.resolution.logSummary(reporter.log);
       return library;
     });
   }
@@ -1144,7 +1000,7 @@ abstract class Compiler extends DiagnosticListener {
     phase = PHASE_RESOLVING;
     if (analyzeAll) {
       libraryLoader.libraries.forEach((LibraryElement library) {
-        log('Enqueuing ${library.canonicalUri}');
+      reporter.log('Enqueuing ${library.canonicalUri}');
         fullyEnqueueLibrary(library, enqueuer.resolution);
       });
     } else if (analyzeMain && mainApp != null) {
@@ -1154,30 +1010,11 @@ abstract class Compiler extends DiagnosticListener {
     // that are not pulled in by a particular element.
     backend.enqueueHelpers(enqueuer.resolution, globalDependencies);
     resolveLibraryMetadata();
-    log('Resolving...');
+    reporter.log('Resolving...');
     processQueue(enqueuer.resolution, mainFunction);
-    enqueuer.resolution.logSummary(log);
+    enqueuer.resolution.logSummary(reporter.log);
 
-    if (!showPackageWarnings && !suppressWarnings) {
-      suppressedWarnings.forEach((Uri uri, SuppressionInfo info) {
-        MessageKind kind = MessageKind.HIDDEN_WARNINGS_HINTS;
-        if (info.warnings == 0) {
-          kind = MessageKind.HIDDEN_HINTS;
-        } else if (info.hints == 0) {
-          kind = MessageKind.HIDDEN_WARNINGS;
-        }
-        MessageTemplate template = MessageTemplate.TEMPLATES[kind];
-        Message message = template.message(
-            {'warnings': info.warnings,
-             'hints': info.hints,
-             'uri': uri},
-            terseDiagnostics);
-        reportDiagnostic(
-            new DiagnosticMessage(null, null, message),
-            const <DiagnosticMessage>[],
-            api.Diagnostic.HINT);
-      });
-    }
+    _reporter.reportSuppressedMessagesSummary();
 
     if (compilationFailed){
       if (!generateCodeWithCompileTimeErrors) return;
@@ -1208,14 +1045,14 @@ abstract class Compiler extends DiagnosticListener {
 
     deferredLoadTask.onResolutionComplete(mainFunction);
 
-    log('Inferring types...');
+    reporter.log('Inferring types...');
     typesTask.onResolutionComplete(mainFunction);
 
     if (stopAfterTypeInference) return;
 
     backend.onTypeInferenceComplete();
 
-    log('Compiling...');
+    reporter.log('Compiling...');
     phase = PHASE_COMPILING;
     backend.onCodegenStart();
     // TODO(johnniwinther): Move these to [CodegenEnqueuer].
@@ -1228,7 +1065,7 @@ abstract class Compiler extends DiagnosticListener {
       });
     }
     processQueue(enqueuer.codegen, mainFunction);
-    enqueuer.codegen.logSummary(log);
+    enqueuer.codegen.logSummary(reporter.log);
 
     int programSize = backend.assembleProgram();
 
@@ -1277,7 +1114,7 @@ abstract class Compiler extends DiagnosticListener {
    */
   void emptyQueue(Enqueuer world) {
     world.forEach((WorkItem work) {
-      withCurrentElement(work.element, () {
+    reporter.withCurrentElement(work.element, () {
         world.applyImpact(work.element, work.run(this, world));
       });
     });
@@ -1319,7 +1156,7 @@ abstract class Compiler extends DiagnosticListener {
   checkQueues() {
     for (Enqueuer world in [enqueuer.resolution, enqueuer.codegen]) {
       world.forEach((WorkItem work) {
-        internalError(work.element, "Work list is not empty.");
+        reporter.internalError(work.element, "Work list is not empty.");
       });
     }
     if (!REPORT_EXCESS_RESOLUTION) return;
@@ -1342,9 +1179,9 @@ abstract class Compiler extends DiagnosticListener {
         resolved.remove(e);
       }
     }
-    log('Excess resolution work: ${resolved.length}.');
+    reporter.log('Excess resolution work: ${resolved.length}.');
     for (Element e in resolved) {
-      reportWarningMessage(e,
+      reporter.reportWarningMessage(e,
           MessageKind.GENERIC,
           {'text': 'Warning: $e resolved but not compiled.'});
     }
@@ -1386,7 +1223,8 @@ abstract class Compiler extends DiagnosticListener {
       // TODO(ahe): Add structured diagnostics to the compiler API and
       // use it to separate this from the --verbose option.
       if (phase == PHASE_RESOLVING) {
-        log('Resolved ${enqueuer.resolution.resolvedElements.length} '
+      reporter.log(
+            'Resolved ${enqueuer.resolution.resolvedElements.length} '
             'elements.');
         progress.reset();
       }
@@ -1405,195 +1243,61 @@ abstract class Compiler extends DiagnosticListener {
     if (shouldPrintProgress) {
       // TODO(ahe): Add structured diagnostics to the compiler API and
       // use it to separate this from the --verbose option.
-      log('Compiled ${enqueuer.codegen.generatedCode.length} methods.');
+      reporter.log(
+          'Compiled ${enqueuer.codegen.generatedCode.length} methods.');
       progress.reset();
     }
     return backend.codegen(work);
   }
 
-  DiagnosticMessage createMessage(
-      Spannable spannable,
-      MessageKind messageKind,
-      [Map arguments = const {}]) {
-    SourceSpan span = spanFromSpannable(spannable);
-    MessageTemplate template = MessageTemplate.TEMPLATES[messageKind];
-    Message message = template.message(arguments, terseDiagnostics);
-    return new DiagnosticMessage(span, spannable, message);
-  }
+  void reportDiagnostic(DiagnosticMessage message,
+                        List<DiagnosticMessage> infos,
+                        api.Diagnostic kind);
 
-  void reportError(
-      DiagnosticMessage message,
-      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
-    reportDiagnosticInternal(message, infos, api.Diagnostic.ERROR);
+  void reportCrashInUserCode(String message, exception, stackTrace) {
+    _reporter.onCrashInUserCode(message, exception, stackTrace);
   }
 
-  void reportWarning(
-      DiagnosticMessage message,
-      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
-    reportDiagnosticInternal(message, infos, api.Diagnostic.WARNING);
+  /**
+   * Translates the [resolvedUri] into a readable URI.
+   *
+   * The [importingLibrary] holds the library importing [resolvedUri] or
+   * [:null:] if [resolvedUri] is loaded as the main library. The
+   * [importingLibrary] is used to grant access to internal libraries from
+   * platform libraries and patch libraries.
+   *
+   * If the [resolvedUri] is not accessible from [importingLibrary], this method
+   * is responsible for reporting errors.
+   *
+   * See [LibraryLoader] for terminology on URIs.
+   */
+  Uri translateResolvedUri(LibraryElement importingLibrary,
+                           Uri resolvedUri, Spannable spannable) {
+    unimplemented(importingLibrary, 'Compiler.translateResolvedUri');
+    return null;
   }
 
-  void reportHint(
-      DiagnosticMessage message,
-      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
-    reportDiagnosticInternal(message, infos, api.Diagnostic.HINT);
+  /**
+   * Reads the script specified by the [readableUri].
+   *
+   * See [LibraryLoader] for terminology on URIs.
+   */
+  Future<Script> readScript(Spannable node, Uri readableUri) {
+    unimplemented(node, 'Compiler.readScript');
+    return null;
   }
 
-  @deprecated
-  void reportInfo(Spannable node, MessageKind messageKind,
-                  [Map arguments = const {}]) {
-    reportDiagnosticInternal(
-        createMessage(node, messageKind, arguments),
-        const <DiagnosticMessage>[],
-        api.Diagnostic.INFO);
+  /// Compatible with [readScript] and used by [LibraryLoader] to create
+  /// synthetic scripts to recover from read errors and bad URIs.
+  Future<Script> synthesizeScript(Spannable node, Uri readableUri) {
+    unimplemented(node, 'Compiler.synthesizeScript');
+    return null;
   }
 
-  void reportDiagnosticInternal(DiagnosticMessage message,
-                                List<DiagnosticMessage> infos,
-                                api.Diagnostic kind) {
-    if (!showPackageWarnings && message.spannable != NO_LOCATION_SPANNABLE) {
-      switch (kind) {
-      case api.Diagnostic.WARNING:
-      case api.Diagnostic.HINT:
-        Element element = elementFromSpannable(message.spannable);
-        if (!inUserCode(element, assumeInUserCode: true)) {
-          Uri uri = getCanonicalUri(element);
-          SuppressionInfo info =
-              suppressedWarnings.putIfAbsent(uri, () => new SuppressionInfo());
-          if (kind == api.Diagnostic.WARNING) {
-            info.warnings++;
-          } else {
-            info.hints++;
-          }
-          lastDiagnosticWasFiltered = true;
-          return;
-        }
-        break;
-      case api.Diagnostic.INFO:
-        if (lastDiagnosticWasFiltered) {
-          return;
-        }
-        break;
-      }
-    }
-    lastDiagnosticWasFiltered = false;
-    reportDiagnostic(message, infos, kind);
-  }
-
-  void reportDiagnostic(DiagnosticMessage message,
-                        List<DiagnosticMessage> infos,
-                        api.Diagnostic kind);
-
-  void reportAssertionFailure(SpannableAssertionFailure ex) {
-    String message = (ex.message != null) ? tryToString(ex.message)
-                                          : tryToString(ex);
-    reportDiagnosticInternal(
-        createMessage(ex.node, MessageKind.GENERIC, {'text': message}),
-        const <DiagnosticMessage>[],
-        api.Diagnostic.CRASH);
-  }
-
-  SourceSpan spanFromTokens(Token begin, Token end, [Uri uri]) {
-    if (begin == null || end == null) {
-      // TODO(ahe): We can almost always do better. Often it is only
-      // end that is null. Otherwise, we probably know the current
-      // URI.
-      throw 'Cannot find tokens to produce error message.';
-    }
-    if (uri == null && currentElement != null) {
-      uri = currentElement.compilationUnit.script.resourceUri;
-    }
-    return new SourceSpan.fromTokens(uri, begin, end);
-  }
-
-  SourceSpan spanFromNode(Node node) {
-    return spanFromTokens(node.getBeginToken(), node.getEndToken());
-  }
-
-  SourceSpan spanFromElement(Element element) {
-    if (element != null && element.sourcePosition != null) {
-      return element.sourcePosition;
-    }
-    while (element != null && element.isSynthesized) {
-      element = element.enclosingElement;
-    }
-    if (element != null &&
-        element.sourcePosition == null &&
-        !element.isLibrary &&
-        !element.isCompilationUnit) {
-      // Sometimes, the backend fakes up elements that have no
-      // position. So we use the enclosing element instead. It is
-      // not a good error location, but cancel really is "internal
-      // error" or "not implemented yet", so the vicinity is good
-      // enough for now.
-      element = element.enclosingElement;
-      // TODO(ahe): I plan to overhaul this infrastructure anyways.
-    }
-    if (element == null) {
-      element = currentElement;
-    }
-    if (element == null) {
-      return null;
-    }
-
-    if (element.sourcePosition != null) {
-      return element.sourcePosition;
-    }
-    Token position = element.position;
-    Uri uri = element.compilationUnit.script.resourceUri;
-    return (position == null)
-        ? new SourceSpan(uri, 0, 0)
-        : spanFromTokens(position, position, uri);
-  }
-
-  SourceSpan spanFromHInstruction(HInstruction instruction) {
-    Element element = _elementFromHInstruction(instruction);
-    if (element == null) element = currentElement;
-    SourceInformation position = instruction.sourceInformation;
-    if (position == null) return spanFromElement(element);
-    return position.sourceSpan;
-  }
-
-  /**
-   * Translates the [resolvedUri] into a readable URI.
-   *
-   * The [importingLibrary] holds the library importing [resolvedUri] or
-   * [:null:] if [resolvedUri] is loaded as the main library. The
-   * [importingLibrary] is used to grant access to internal libraries from
-   * platform libraries and patch libraries.
-   *
-   * If the [resolvedUri] is not accessible from [importingLibrary], this method
-   * is responsible for reporting errors.
-   *
-   * See [LibraryLoader] for terminology on URIs.
-   */
-  Uri translateResolvedUri(LibraryElement importingLibrary,
-                           Uri resolvedUri, Spannable spannable) {
-    unimplemented(importingLibrary, 'Compiler.translateResolvedUri');
-    return null;
-  }
-
-  /**
-   * Reads the script specified by the [readableUri].
-   *
-   * See [LibraryLoader] for terminology on URIs.
-   */
-  Future<Script> readScript(Spannable node, Uri readableUri) {
-    unimplemented(node, 'Compiler.readScript');
-    return null;
-  }
-
-  /// Compatible with [readScript] and used by [LibraryLoader] to create
-  /// synthetic scripts to recover from read errors and bad URIs.
-  Future<Script> synthesizeScript(Spannable node, Uri readableUri) {
-    unimplemented(node, 'Compiler.synthesizeScript');
-    return null;
-  }
-
-  Element lookupElementIn(ScopeContainerElement container, String name) {
-    Element element = container.localLookup(name);
-    if (element == null) {
-      throw 'Could not find $name in $container';
+  Element lookupElementIn(ScopeContainerElement container, String name) {
+    Element element = container.localLookup(name);
+    if (element == null) {
+      throw 'Could not find $name in $container';
     }
     return element;
   }
@@ -1627,19 +1331,19 @@ abstract class Compiler extends DiagnosticListener {
       if (member.isErroneous) return;
       if (member.isFunction) {
         if (!enqueuer.resolution.hasBeenResolved(member)) {
-          reportHintMessage(
+          reporter.reportHintMessage(
               member, MessageKind.UNUSED_METHOD, {'name': member.name});
         }
       } else if (member.isClass) {
         if (!member.isResolved) {
-          reportHintMessage(
+          reporter.reportHintMessage(
               member, MessageKind.UNUSED_CLASS, {'name': member.name});
         } else {
           member.forEachLocalMember(checkLive);
         }
       } else if (member.isTypedef) {
         if (!member.isResolved) {
-          reportHintMessage(
+          reporter.reportHintMessage(
               member, MessageKind.UNUSED_TYPEDEF, {'name': member.name});
         }
       }
@@ -1869,6 +1573,350 @@ class _CompilerCoreTypes implements CoreTypes {
   }
 }
 
+class _CompilerDiagnosticReporter extends DiagnosticReporter {
+  final Compiler compiler;
+  final DiagnosticOptions options;
+
+  Element _currentElement;
+  bool hasCrashed = false;
+
+  /// `true` if the last diagnostic was filtered, in which case the
+  /// accompanying info message should be filtered as well.
+  bool lastDiagnosticWasFiltered = false;
+
+  /// Map containing information about the warnings and hints that have been
+  /// suppressed for each library.
+  Map<Uri, SuppressionInfo> suppressedWarnings = <Uri, SuppressionInfo>{};
+
+  _CompilerDiagnosticReporter(this.compiler, this.options);
+
+  Element get currentElement => _currentElement;
+
+  DiagnosticMessage createMessage(
+      Spannable spannable,
+      MessageKind messageKind,
+      [Map arguments = const {}]) {
+    SourceSpan span = spanFromSpannable(spannable);
+    MessageTemplate template = MessageTemplate.TEMPLATES[messageKind];
+    Message message = template.message(arguments, options.terseDiagnostics);
+    return new DiagnosticMessage(span, spannable, message);
+  }
+
+  void reportError(
+      DiagnosticMessage message,
+      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
+    reportDiagnosticInternal(message, infos, api.Diagnostic.ERROR);
+  }
+
+  void reportWarning(
+      DiagnosticMessage message,
+      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
+    reportDiagnosticInternal(message, infos, api.Diagnostic.WARNING);
+  }
+
+  void reportHint(
+      DiagnosticMessage message,
+      [List<DiagnosticMessage> infos = const <DiagnosticMessage>[]]) {
+    reportDiagnosticInternal(message, infos, api.Diagnostic.HINT);
+  }
+
+  @deprecated
+  void reportInfo(Spannable node, MessageKind messageKind,
+                  [Map arguments = const {}]) {
+    reportDiagnosticInternal(
+        createMessage(node, messageKind, arguments),
+        const <DiagnosticMessage>[],
+        api.Diagnostic.INFO);
+  }
+
+  void reportDiagnosticInternal(DiagnosticMessage message,
+                                List<DiagnosticMessage> infos,
+                                api.Diagnostic kind) {
+    if (!options.showPackageWarnings &&
+        message.spannable != NO_LOCATION_SPANNABLE) {
+      switch (kind) {
+      case api.Diagnostic.WARNING:
+      case api.Diagnostic.HINT:
+        Element element = elementFromSpannable(message.spannable);
+        if (!compiler.inUserCode(element, assumeInUserCode: true)) {
+          Uri uri = compiler.getCanonicalUri(element);
+          SuppressionInfo info =
+              suppressedWarnings.putIfAbsent(uri, () => new SuppressionInfo());
+          if (kind == api.Diagnostic.WARNING) {
+            info.warnings++;
+          } else {
+            info.hints++;
+          }
+          lastDiagnosticWasFiltered = true;
+          return;
+        }
+        break;
+      case api.Diagnostic.INFO:
+        if (lastDiagnosticWasFiltered) {
+          return;
+        }
+        break;
+      }
+    }
+    lastDiagnosticWasFiltered = false;
+    reportDiagnostic(message, infos, kind);
+  }
+
+  void reportDiagnostic(DiagnosticMessage message,
+                        List<DiagnosticMessage> infos,
+                        api.Diagnostic kind) {
+    compiler.reportDiagnostic(message, infos, kind);
+  }
+
+  /**
+   * Perform an operation, [f], returning the return value from [f].  If an
+   * error occurs then report it as having occurred during compilation of
+   * [element].  Can be nested.
+   */
+  withCurrentElement(Element element, f()) {
+    Element old = currentElement;
+    _currentElement = element;
+    try {
+      return f();
+    } on SpannableAssertionFailure catch (ex) {
+      if (!hasCrashed) {
+        reportAssertionFailure(ex);
+        pleaseReportCrash();
+      }
+      hasCrashed = true;
+      rethrow;
+    } on StackOverflowError {
+      // We cannot report anything useful in this case, because we
+      // do not have enough stack space.
+      rethrow;
+    } catch (ex) {
+      if (hasCrashed) rethrow;
+      try {
+        unhandledExceptionOnElement(element);
+      } catch (doubleFault) {
+        // Ignoring exceptions in exception handling.
+      }
+      rethrow;
+    } finally {
+      _currentElement = old;
+    }
+  }
+
+  void reportAssertionFailure(SpannableAssertionFailure ex) {
+    String message = (ex.message != null) ? tryToString(ex.message)
+                                          : tryToString(ex);
+    reportDiagnosticInternal(
+        createMessage(ex.node, MessageKind.GENERIC, {'text': message}),
+        const <DiagnosticMessage>[],
+        api.Diagnostic.CRASH);
+  }
+
+  SourceSpan spanFromTokens(Token begin, Token end, [Uri uri]) {
+    if (begin == null || end == null) {
+      // TODO(ahe): We can almost always do better. Often it is only
+      // end that is null. Otherwise, we probably know the current
+      // URI.
+      throw 'Cannot find tokens to produce error message.';
+    }
+    if (uri == null && currentElement != null) {
+      uri = currentElement.compilationUnit.script.resourceUri;
+    }
+    return new SourceSpan.fromTokens(uri, begin, end);
+  }
+
+  SourceSpan spanFromNode(Node node) {
+    return spanFromTokens(node.getBeginToken(), node.getEndToken());
+  }
+
+  SourceSpan spanFromElement(Element element) {
+    if (element != null && element.sourcePosition != null) {
+      return element.sourcePosition;
+    }
+    while (element != null && element.isSynthesized) {
+      element = element.enclosingElement;
+    }
+    if (element != null &&
+        element.sourcePosition == null &&
+        !element.isLibrary &&
+        !element.isCompilationUnit) {
+      // Sometimes, the backend fakes up elements that have no
+      // position. So we use the enclosing element instead. It is
+      // not a good error location, but cancel really is "internal
+      // error" or "not implemented yet", so the vicinity is good
+      // enough for now.
+      element = element.enclosingElement;
+      // TODO(ahe): I plan to overhaul this infrastructure anyways.
+    }
+    if (element == null) {
+      element = currentElement;
+    }
+    if (element == null) {
+      return null;
+    }
+
+    if (element.sourcePosition != null) {
+      return element.sourcePosition;
+    }
+    Token position = element.position;
+    Uri uri = element.compilationUnit.script.resourceUri;
+    return (position == null)
+        ? new SourceSpan(uri, 0, 0)
+        : spanFromTokens(position, position, uri);
+  }
+
+  SourceSpan spanFromHInstruction(HInstruction instruction) {
+    Element element = _elementFromHInstruction(instruction);
+    if (element == null) element = currentElement;
+    SourceInformation position = instruction.sourceInformation;
+    if (position == null) return spanFromElement(element);
+    return position.sourceSpan;
+  }
+
+  SourceSpan spanFromSpannable(Spannable node) {
+    // TODO(johnniwinther): Disallow `node == null` ?
+    if (node == null) return null;
+    if (node == CURRENT_ELEMENT_SPANNABLE) {
+      node = currentElement;
+    } else if (node == NO_LOCATION_SPANNABLE) {
+      if (currentElement == null) return null;
+      node = currentElement;
+    }
+    if (node is SourceSpan) {
+      return node;
+    } else if (node is Node) {
+      return spanFromNode(node);
+    } else if (node is TokenPair) {
+      return spanFromTokens(node.begin, node.end);
+    } else if (node is Token) {
+      return spanFromTokens(node, node);
+    } else if (node is HInstruction) {
+      return spanFromHInstruction(node);
+    } else if (node is Element) {
+      return spanFromElement(node);
+    } else if (node is MetadataAnnotation) {
+      Uri uri = node.annotatedElement.compilationUnit.script.resourceUri;
+      return spanFromTokens(node.beginToken, node.endToken, uri);
+    } else if (node is Local) {
+      Local local = node;
+      return spanFromElement(local.executableContext);
+    } else {
+      throw 'No error location.';
+    }
+  }
+
+  Element _elementFromHInstruction(HInstruction instruction) {
+    return instruction.sourceElement is Element
+        ? instruction.sourceElement : null;
+  }
+
+  internalError(Spannable node, reason) {
+    String message = tryToString(reason);
+    reportDiagnosticInternal(
+        createMessage(node, MessageKind.GENERIC, {'text': message}),
+        const <DiagnosticMessage>[],
+        api.Diagnostic.CRASH);
+    throw 'Internal Error: $message';
+  }
+
+  void unhandledExceptionOnElement(Element element) {
+    if (hasCrashed) return;
+    hasCrashed = true;
+    reportDiagnostic(
+        createMessage(element, MessageKind.COMPILER_CRASHED),
+        const <DiagnosticMessage>[],
+        api.Diagnostic.CRASH);
+    pleaseReportCrash();
+  }
+
+  void pleaseReportCrash() {
+    print(
+        MessageTemplate.TEMPLATES[MessageKind.PLEASE_REPORT_THE_CRASH]
+            .message({'buildId': compiler.buildId}));
+  }
+
+  /// Finds the approximate [Element] for [node]. [currentElement] is used as
+  /// the default value.
+  Element elementFromSpannable(Spannable node) {
+    Element element;
+    if (node is Element) {
+      element = node;
+    } else if (node is HInstruction) {
+      element = _elementFromHInstruction(node);
+    } else if (node is MetadataAnnotation) {
+      element = node.annotatedElement;
+    }
+    return element != null ? element : currentElement;
+  }
+
+  void log(message) {
+    Message msg = MessageTemplate.TEMPLATES[MessageKind.GENERIC]
+        .message({'text': '$message'});
+    reportDiagnostic(
+        new DiagnosticMessage(null, null, msg),
+        const <DiagnosticMessage>[],
+        api.Diagnostic.VERBOSE_INFO);
+  }
+
+  String tryToString(object) {
+    try {
+      return object.toString();
+    } catch (_) {
+      return '<exception in toString()>';
+    }
+  }
+
+  onError(Uri uri, error) {
+    try {
+      if (!hasCrashed) {
+        hasCrashed = true;
+        if (error is SpannableAssertionFailure) {
+          reportAssertionFailure(error);
+        } else {
+          reportDiagnostic(
+              createMessage(
+                  new SourceSpan(uri, 0, 0),
+                  MessageKind.COMPILER_CRASHED),
+              const <DiagnosticMessage>[],
+              api.Diagnostic.CRASH);
+        }
+        pleaseReportCrash();
+      }
+    } catch (doubleFault) {
+      // Ignoring exceptions in exception handling.
+    }
+    throw error;
+  }
+
+  void onCrashInUserCode(String message, exception, stackTrace) {
+    hasCrashed = true;
+    print('$message: ${tryToString(exception)}');
+    print(tryToString(stackTrace));
+  }
+
+  void reportSuppressedMessagesSummary() {
+    if (!options.showPackageWarnings && !options.suppressWarnings) {
+      suppressedWarnings.forEach((Uri uri, SuppressionInfo info) {
+        MessageKind kind = MessageKind.HIDDEN_WARNINGS_HINTS;
+        if (info.warnings == 0) {
+          kind = MessageKind.HIDDEN_HINTS;
+        } else if (info.hints == 0) {
+          kind = MessageKind.HIDDEN_WARNINGS;
+        }
+        MessageTemplate template = MessageTemplate.TEMPLATES[kind];
+        Message message = template.message(
+            {'warnings': info.warnings,
+             'hints': info.hints,
+             'uri': uri},
+             options.terseDiagnostics);
+        reportDiagnostic(
+            new DiagnosticMessage(null, null, message),
+            const <DiagnosticMessage>[],
+            api.Diagnostic.HINT);
+      });
+    }
+  }
+}
+
 // TODO(johnniwinther): Move [ResolverTask] here.
 class _CompilerResolution implements Resolution {
   final Compiler compiler;
@@ -1876,7 +1924,7 @@ class _CompilerResolution implements Resolution {
   _CompilerResolution(this.compiler);
 
   @override
-  DiagnosticListener get listener => compiler;
+  DiagnosticReporter get reporter => compiler.reporter;
 
   @override
   Parsing get parsing => compiler.parsing;
@@ -1923,7 +1971,7 @@ class _CompilerParsing implements Parsing {
   _CompilerParsing(this.compiler);
 
   @override
-  DiagnosticListener get listener => compiler;
+  DiagnosticReporter get reporter => compiler.reporter;
 
   @override
   measure(f()) => compiler.parser.measure(f);