Limit hints on empty hide on package imports.

pkg/compiler/lib/src/library_loader.dart

 // Copyright (c) 2012, 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 dart2js.library_loader;
 
 import 'dart:async';
 
 import 'common/names.dart' show
     Uris;
@@ skipping 881 matching lines @@
                               CombinatorFilter filter) {
     assert(invariant(library, exportedLibraryElement.exportsHandled));
     exportedLibraryElement.forEachExport((Element exportedElement) {
       if (!filter.exclude(exportedElement)) {
         Link<ExportElement> exports =
             pendingExportMap.putIfAbsent(exportedElement,
                                          () => const Link<ExportElement>());
         pendingExportMap[exportedElement] = exports.prepend(export);
       }
     });
-    reporter.withCurrentElement(library, () {
-      checkLibraryDependency(reporter, export.node, exportedLibraryElement);
-    });
+    if (!reporter.options.suppressHints) {
+      reporter.withCurrentElement(library, () {
+        checkLibraryDependency(reporter, export.node, exportedLibraryElement);
+      });
+    }
   }
 
   /**
    * Registers the compute export scope with the node library.
    */
   void registerExports() {
     library.setExports(exportScope.values.toList());
   }
 
   /**
@@ skipping 147 matching lines @@
   void checkLibraryDependency(
       DiagnosticReporter reporter,
       LibraryDependency tag,
       LibraryElement library) {
     if (tag == null || tag.combinators == null) return;
     for (Combinator combinator in tag.combinators) {
       for (Identifier identifier in combinator.identifiers) {
         String name = identifier.source;
         Element element = library.findExported(name);
         if (element == null) {
-          reporter.reportHintMessage(
-              identifier,
-              combinator.isHide
-                  ? MessageKind.EMPTY_HIDE : MessageKind.EMPTY_SHOW,
-              {'uri': library.canonicalUri,
-               'name': name});
+          if (combinator.isHide) {
+            if (library.isPackageLibrary &&
+                !reporter.options.showPackageWarnings) {
+              // Only report hide hint on packages if we show warnings on these:
+              // The hide may be non-empty in some versions of the package, in
+              // which case you shouldn't remove the combinator.
+              continue;
+            }
+            reporter.reportHintMessage(
+                identifier,
+                MessageKind.EMPTY_HIDE,
+                {'uri': library.canonicalUri,
+                 'name': name});
+          } else {
+            reporter.reportHintMessage(
+                identifier,
+                MessageKind.EMPTY_SHOW,
+                {'uri': library.canonicalUri,
+                 'name': name});
+          }
         }
       }
     }
   }
 
 }
 
 /**
  * Helper class used for computing the possibly cyclic import/export scopes of
  * a set of libraries.
@@ skipping 61 matching lines @@
     // imports.
     nodeMap.forEach((LibraryElement library, LibraryDependencyNode node) {
       node.registerExports();
     });
 
     // Setup import scopes.
     nodeMap.forEach((LibraryElement library, LibraryDependencyNode node) {
       node.registerImports(reporter);
     });
 
-    nodeMap.forEach((LibraryElement library, LibraryDependencyNode node) {
-      node.checkCombinators(reporter);
-    });
+    if (!reporter.options.suppressHints) {
+      nodeMap.forEach((LibraryElement library, LibraryDependencyNode node) {
+        node.checkCombinators(reporter);
+      });
+    }
   }
 
   /// Registers that [library] depends on [loadedLibrary] through
   /// [libraryDependency].
   void registerDependency(LibraryElementX library,
                           LibraryDependencyElementX libraryDependency,
                           LibraryElement loadedLibrary) {
     if (libraryDependency.isExport) {
       // [loadedLibrary] is exported by [library].
       LibraryDependencyNode exportingNode = nodeMap[library];
@@ skipping 160 matching lines @@
         }
         suffixes.add(const Link<Uri>().prepend(canonicalUri));
       }
       suffixChainMap[library] = suffixes;
       return;
     }
 
     computeSuffixes(rootLibrary, const Link<Uri>());
   }
 }