Warn about overriding operator== but not hashCode.

dart/sdk/lib/_internal/compiler/implementation/source_file_provider.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library source_file_provider;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:utf';
 
@@ skipping 35 matching lines @@
         relativize(cwd, resourceUri, isWindows), source);
     return new Future.value(source);
   }
 
   Future<String> call(Uri resourceUri) => readStringFromUri(resourceUri);
 }
 
 class FormattingDiagnosticHandler {
   final SourceFileProvider provider;
   bool showWarnings = true;
+  bool showHints = true;
   bool verbose = false;
   bool isAborting = false;
   bool enableColors = false;
   bool throwOnError = false;
+  api.Diagnostic lastKind = null;
 
   final int FATAL = api.Diagnostic.CRASH.ordinal | api.Diagnostic.ERROR.ordinal;
   final int INFO =
       api.Diagnostic.INFO.ordinal | api.Diagnostic.VERBOSE_INFO.ordinal;
 
   FormattingDiagnosticHandler([SourceFileProvider provider])
       : this.provider =
           (provider == null) ? new SourceFileProvider() : provider;
 
   void info(var message, [api.Diagnostic kind = api.Diagnostic.VERBOSE_INFO]) {
-    if (!verbose && identical(kind, api.Diagnostic.VERBOSE_INFO)) return;
+    if (!verbose && kind == api.Diagnostic.VERBOSE_INFO) return;
     if (enableColors) {
       print('${colors.green("info:")} $message');
     } else {
       print('info: $message');
     }
   }
 
   void diagnosticHandler(Uri uri, int begin, int end, String message,
                          api.Diagnostic kind) {
     // TODO(ahe): Remove this when source map is handled differently.
     if (identical(kind.name, 'source map')) return;
 
     if (isAborting) return;
-    isAborting = identical(kind, api.Diagnostic.CRASH);
+    isAborting = (kind == api.Diagnostic.CRASH);
     bool fatal = (kind.ordinal & FATAL) != 0;
     bool isInfo = (kind.ordinal & INFO) != 0;
-    if (isInfo && uri == null && !identical(kind, api.Diagnostic.INFO)) {
+    if (isInfo && uri == null && kind != api.Diagnostic.INFO) {
       info(message, kind);
       return;
     }
+    // [previousKind]/[lastKind] records the previous non-INFO kind we saw.
+    // This is used to suppress info about a warning when warnings are
+    // suppressed, and similar for hints.
+    var previousKind = lastKind;
+    if (previousKind != api.Diagnostic.INFO) {
+      lastKind = kind;
+    }
     var color;
-    if (!enableColors) {
-      color = (x) => x;
-    } else if (identical(kind, api.Diagnostic.ERROR)) {
+    if (kind == api.Diagnostic.ERROR) {
       color = colors.red;
-    } else if (identical(kind, api.Diagnostic.WARNING)) {
+    } else if (kind == api.Diagnostic.WARNING) {
+      if (!showWarnings) return;
       color = colors.magenta;
-    } else if (identical(kind, api.Diagnostic.LINT)) {
-      color = colors.magenta;
-    } else if (identical(kind, api.Diagnostic.CRASH)) {
+    } else if (kind == api.Diagnostic.HINT) {
+      if (!showHints) return;
+      color = colors.cyan;
+    } else if (kind == api.Diagnostic.CRASH) {
       color = colors.red;
-    } else if (identical(kind, api.Diagnostic.INFO)) {
+    } else if (kind == api.Diagnostic.INFO) {
+      if (lastKind == api.Diagnostic.WARNING && !showWarnings) return;
+      if (lastKind == api.Diagnostic.HINT && !showHints) return;
       color = colors.green;
     } else {
       throw 'Unknown kind: $kind (${kind.ordinal})';
     }
+    if (!enableColors) {
+      color = (x) => x;
+    }
     if (uri == null) {
       assert(fatal);
       print(color(message));
-    } else if (fatal || showWarnings) {
+    } else {
       SourceFile file = provider.sourceFiles[uri.toString()];
       if (file == null) {
         throw '$uri: file is null';
       }
       print(file.getLocationMessage(color(message), begin, end, true, color));
     }
     if (fatal && throwOnError) {
       isAborting = true;
       throw new AbortLeg(message);
     }
   }
 
   void call(Uri uri, int begin, int end, String message, api.Diagnostic kind) {
     return diagnosticHandler(uri, begin, end, message, kind);
   }
 }