diff --git a/pkg/analyzer/lib/src/dart/analysis/file_state.dart b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
index ae15012012e..74cf10a0a32 100644
--- a/pkg/analyzer/lib/src/dart/analysis/file_state.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
@@ -101,8 +101,8 @@ class FileState {
   Set<FileState> _transitiveFiles;
   String _transitiveSignature;
 
-  List<TopLevelDeclaration> _topLevelDeclarations;
-  List<TopLevelDeclaration> _exportedTopLevelDeclarations;
+  Map<String, TopLevelDeclaration> _topLevelDeclarations;
+  Map<String, TopLevelDeclaration> _exportedTopLevelDeclarations;
 
   FileState._(this._fsState, this.path, this.uri, this.source);
 
@@ -133,47 +133,43 @@ class FileState {
   List<FileState> get exportedFiles => _exportedFiles;
 
   /**
-   * Return [TopLevelDeclaration]s exported from the this library file.
+   * Return [TopLevelDeclaration]s exported from the this library file. The
+   * keys to the map are names of declarations.
    */
-  List<TopLevelDeclaration> get exportedTopLevelDeclarations {
+  Map<String, TopLevelDeclaration> get exportedTopLevelDeclarations {
     if (_exportedTopLevelDeclarations == null) {
-      _exportedTopLevelDeclarations = <TopLevelDeclaration>[];
+      _exportedTopLevelDeclarations = <String, TopLevelDeclaration>{};
 
       Set<FileState> seenLibraries = new Set<FileState>();
 
       /**
        * Compute [TopLevelDeclaration]s exported from the [library].
        */
-      List<TopLevelDeclaration> computeExported(FileState library) {
+      Map<String, TopLevelDeclaration> computeExported(FileState library) {
         var declarations = <String, TopLevelDeclaration>{};
         if (seenLibraries.add(library)) {
-          // Append the library declarations.
-          for (TopLevelDeclaration t in library.topLevelDeclarations) {
-            declarations[t.name] = t;
-          }
-          for (FileState part in library.partedFiles) {
-            for (TopLevelDeclaration t in part.topLevelDeclarations) {
-              declarations[t.name] = t;
-            }
-          }
-
           // Append the exported declarations.
           for (int i = 0; i < library._exportedFiles.length; i++) {
-            List<TopLevelDeclaration> exported =
+            Map<String, TopLevelDeclaration> exported =
                 computeExported(library._exportedFiles[i]);
-            for (TopLevelDeclaration t in exported) {
-              if (!declarations.containsKey(t.name) &&
-                  library._exportFilters[i].accepts(t.name)) {
+            for (TopLevelDeclaration t in exported.values) {
+              if (library._exportFilters[i].accepts(t.name)) {
                 declarations[t.name] = t;
               }
             }
           }
 
+          // Append the library declarations.
+          declarations.addAll(library.topLevelDeclarations);
+          for (FileState part in library.partedFiles) {
+            declarations.addAll(part.topLevelDeclarations);
+          }
+
           // We're done with this library.
           seenLibraries.remove(library);
         }
 
-        return declarations.values.toList();
+        return declarations;
       }
 
       _exportedTopLevelDeclarations = computeExported(this);
@@ -224,15 +220,16 @@ class FileState {
   Set<String> get referencedNames => _referencedNames;
 
   /**
-   * Return public top-level declarations declared in the file.
+   * Return public top-level declarations declared in the file. The keys to the
+   * map are names of declarations.
    */
-  List<TopLevelDeclaration> get topLevelDeclarations {
+  Map<String, TopLevelDeclaration> get topLevelDeclarations {
     if (_topLevelDeclarations == null) {
-      _topLevelDeclarations = <TopLevelDeclaration>[];
+      _topLevelDeclarations = <String, TopLevelDeclaration>{};
 
       void addDeclaration(TopLevelDeclarationKind kind, String name) {
         if (!name.startsWith('_')) {
-          _topLevelDeclarations.add(new TopLevelDeclaration(kind, name));
+          _topLevelDeclarations[name] = new TopLevelDeclaration(kind, name);
         }
       }
 
diff --git a/pkg/analyzer/test/src/dart/analysis/file_state_test.dart b/pkg/analyzer/test/src/dart/analysis/file_state_test.dart
index 8a3a8da40a8..bb45ad1dd7f 100644
--- a/pkg/analyzer/test/src/dart/analysis/file_state_test.dart
+++ b/pkg/analyzer/test/src/dart/analysis/file_state_test.dart
@@ -73,8 +73,9 @@ export 'a.dart';
 class B {}
 ''');
     FileState file = fileSystemState.getFileForPath(b);
-    List<TopLevelDeclaration> declarations = file.exportedTopLevelDeclarations;
-    expect(declarations.map((t) => t.name), unorderedEquals(['A', 'B']));
+    Map<String, TopLevelDeclaration> declarations =
+        file.exportedTopLevelDeclarations;
+    expect(declarations.keys, unorderedEquals(['A', 'B']));
   }
 
   test_exportedTopLevelDeclarations_export2_show() {
@@ -162,9 +163,10 @@ export 'a.dart';
 int V;
 ''');
     FileState file = fileSystemState.getFileForPath(b);
-    List<TopLevelDeclaration> declarations = file.exportedTopLevelDeclarations;
-    expect(declarations.map((t) => t.name), unorderedEquals(['V']));
-    expect(declarations.single.kind, TopLevelDeclarationKind.variable);
+    Map<String, TopLevelDeclaration> declarations =
+        file.exportedTopLevelDeclarations;
+    expect(declarations.keys, unorderedEquals(['V']));
+    expect(declarations['V'].kind, TopLevelDeclarationKind.variable);
   }
 
   test_exportedTopLevelDeclarations_export_show() {
@@ -499,16 +501,13 @@ set _V3(_) {}
 ''');
     FileState file = fileSystemState.getFileForPath(path);
 
-    List<TopLevelDeclaration> declarations = file.topLevelDeclarations;
+    Map<String, TopLevelDeclaration> declarations = file.topLevelDeclarations;
 
     void assertHas(String name, TopLevelDeclarationKind kind) {
-      expect(
-          declarations,
-          contains(predicate(
-              (TopLevelDeclaration t) => t.name == name && t.kind == kind)));
+      expect(declarations[name]?.kind, kind);
     }
 
-    expect(declarations.map((t) => t.name),
+    expect(declarations.keys,
         unorderedEquals(['C', 'F', 'E', 'f', 'V1', 'V2', 'V3', 'V4']));
     assertHas('C', TopLevelDeclarationKind.type);
     assertHas('F', TopLevelDeclarationKind.type);
@@ -636,8 +635,9 @@ set _V3(_) {}
 
   void _assertExportedTopLevelDeclarations(String path, List<String> expected) {
     FileState file = fileSystemState.getFileForPath(path);
-    List<TopLevelDeclaration> declarations = file.exportedTopLevelDeclarations;
-    expect(declarations.map((t) => t.name), unorderedEquals(expected));
+    Map<String, TopLevelDeclaration> declarations =
+        file.exportedTopLevelDeclarations;
+    expect(declarations.keys, unorderedEquals(expected));
   }
 
   void _assertFilesWithoutTransitiveFiles(List<FileState> expected) {