diff --git a/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart b/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart
index e3e581b5a9d..5a1107c51e2 100644
--- a/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart
+++ b/pkg/analysis_server/test/src/services/correction/fix/change_to_test.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analysis_server/src/services/correction/fix.dart';
+import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
 
@@ -126,7 +127,9 @@ main() {
   c.Future v = null;
   print(v);
 }
-''');
+''', errorFilter: (error) {
+      return error.errorCode == CompileTimeErrorCode.UNDEFINED_CLASS;
+    });
   }
 
   Future<void> test_class_with() async {
@@ -177,7 +180,9 @@ main() {
   c.main();
 }
 ''');
-    await assertNoFix();
+    await assertNoFix(errorFilter: (error) {
+      return error.errorCode == CompileTimeErrorCode.UNDEFINED_FUNCTION;
+    });
   }
 
   Future<void> test_function_thisLibrary() async {
diff --git a/pkg/analyzer/lib/src/error/imports_verifier.dart b/pkg/analyzer/lib/src/error/imports_verifier.dart
index 674e4f554da..8a9b8c35a85 100644
--- a/pkg/analyzer/lib/src/error/imports_verifier.dart
+++ b/pkg/analyzer/lib/src/error/imports_verifier.dart
@@ -217,11 +217,6 @@ class ImportsVerifier {
   /// element, the import directive can be marked as used (removed from the
   /// unusedImports) by looking at the resolved `lib` in `lib.X`, instead of
   /// looking at which library the `lib.X` resolves.
-  ///
-  /// TODO (jwren) Since multiple [ImportDirective]s can share the same
-  /// [PrefixElement], it is possible to have an unreported unused import in
-  /// situations where two imports use the same prefix and at least one import
-  /// directive is used.
   final HashMap<PrefixElement, List<ImportDirective>> _prefixElementMap =
       HashMap<PrefixElement, List<ImportDirective>>();
 
@@ -410,22 +405,21 @@ class ImportsVerifier {
 
   /// Remove elements from [_unusedImports] using the given [usedElements].
   void removeUsedElements(UsedImportedElements usedElements) {
-    // Stop if all the imports and shown names are known to be used.
-    if (_unusedImports.isEmpty && _unusedShownNamesMap.isEmpty) {
-      return;
-    }
+    bool everythingIsKnownToBeUsed() =>
+        _unusedImports.isEmpty && _unusedShownNamesMap.isEmpty;
+
     // Process import prefixes.
     usedElements.prefixMap
         .forEach((PrefixElement prefix, List<Element> elements) {
-      List<ImportDirective> importDirectives = _prefixElementMap[prefix];
-      if (importDirectives != null) {
-        int importLength = importDirectives.length;
-        for (int i = 0; i < importLength; i++) {
-          ImportDirective importDirective = importDirectives[i];
-          _unusedImports.remove(importDirective);
-          int elementLength = elements.length;
-          for (int j = 0; j < elementLength; j++) {
-            Element element = elements[j];
+      if (everythingIsKnownToBeUsed()) {
+        return;
+      }
+      // Find import directives using namespaces.
+      for (var importDirective in _prefixElementMap[prefix] ?? []) {
+        Namespace namespace = _computeNamespace(importDirective);
+        for (var element in elements) {
+          if (namespace?.getPrefixed(prefix.name, element.name) != null) {
+            _unusedImports.remove(importDirective);
             _removeFromUnusedShownNamesMap(element, importDirective);
           }
         }
@@ -433,15 +427,13 @@ class ImportsVerifier {
     });
     // Process top-level elements.
     for (Element element in usedElements.elements) {
-      // Stop if all the imports and shown names are known to be used.
-      if (_unusedImports.isEmpty && _unusedShownNamesMap.isEmpty) {
+      if (everythingIsKnownToBeUsed()) {
         return;
       }
       // Find import directives using namespaces.
-      String name = element.name;
       for (ImportDirective importDirective in _allImports) {
         Namespace namespace = _computeNamespace(importDirective);
-        if (namespace?.get(name) != null) {
+        if (namespace?.get(element.name) != null) {
           _unusedImports.remove(importDirective);
           _removeFromUnusedShownNamesMap(element, importDirective);
         }
@@ -449,15 +441,13 @@ class ImportsVerifier {
     }
     // Process extension elements.
     for (ExtensionElement extensionElement in usedElements.usedExtensions) {
-      // Stop if all the imports and shown names are known to be used.
-      if (_unusedImports.isEmpty && _unusedShownNamesMap.isEmpty) {
+      if (everythingIsKnownToBeUsed()) {
         return;
       }
       // Find import directives using namespaces.
-      String name = extensionElement.name;
       for (ImportDirective importDirective in _allImports) {
         Namespace namespace = _computeNamespace(importDirective);
-        if (namespace?.get(name) == extensionElement) {
+        if (namespace?.get(extensionElement.name) == extensionElement) {
           _unusedImports.remove(importDirective);
           _removeFromUnusedShownNamesMap(extensionElement, importDirective);
         }
diff --git a/pkg/analyzer/test/generated/error_suppression_test.dart b/pkg/analyzer/test/generated/error_suppression_test.dart
index 07a3c23c8eb..87797c50b74 100644
--- a/pkg/analyzer/test/generated/error_suppression_test.dart
+++ b/pkg/analyzer/test/generated/error_suppression_test.dart
@@ -271,7 +271,9 @@ import 'dart:collection' as c;
 // ignore: undefined_prefixed_name
 f() => c.g;
 ''',
-      [],
+      [
+        error(HintCode.UNUSED_IMPORT, 7, 17),
+      ],
     );
   }
 }
diff --git a/pkg/analyzer/test/src/dart/resolution/assignment_test.dart b/pkg/analyzer/test/src/dart/resolution/assignment_test.dart
index d07c1acf4bd..5a9713557b1 100644
--- a/pkg/analyzer/test/src/dart/resolution/assignment_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/assignment_test.dart
@@ -1533,6 +1533,7 @@ main() {
   x = 2;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 37, 1),
     ]);
 
diff --git a/pkg/analyzer/test/src/dart/resolution/import_prefix_test.dart b/pkg/analyzer/test/src/dart/resolution/import_prefix_test.dart
index 66c665f4b3b..362da76db30 100644
--- a/pkg/analyzer/test/src/dart/resolution/import_prefix_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/import_prefix_test.dart
@@ -24,6 +24,7 @@ main() {
   p; // use
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 12),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 38, 1),
     ]);
 
@@ -40,6 +41,7 @@ main() {
   for (var x in p) {}
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 12),
       error(HintCode.UNUSED_LOCAL_VARIABLE, 47, 1),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 52, 1),
     ]);
@@ -64,6 +66,7 @@ main() {
   var x = new C(p);
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 12),
       error(HintCode.UNUSED_LOCAL_VARIABLE, 66, 1),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 76, 1),
     ]);
diff --git a/pkg/analyzer/test/src/dart/resolution/method_invocation_test.dart b/pkg/analyzer/test/src/dart/resolution/method_invocation_test.dart
index 28af7ee3aed..c1ff99bcefe 100644
--- a/pkg/analyzer/test/src/dart/resolution/method_invocation_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/method_invocation_test.dart
@@ -755,6 +755,7 @@ main() {
   math?.loadLibrary();
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 49, 4),
     ]);
 
@@ -778,6 +779,7 @@ main() {
   foo();
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 39, 3),
     ]);
     _assertInvalidInvocation(
@@ -806,6 +808,7 @@ main() {
   math.foo(0);
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.UNDEFINED_FUNCTION, 45, 3),
     ]);
     _assertUnresolvedMethodInvocation('foo(0);');
@@ -1309,13 +1312,15 @@ main() {
   }
 
   test_hasReceiver_deferredImportPrefix_loadLibrary() async {
-    await assertNoErrorsInCode(r'''
+    await assertErrorsInCode(r'''
 import 'dart:math' deferred as math;
 
 main() {
   math.loadLibrary();
 }
-''');
+''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
+    ]);
 
     var import = findElement.importFind('dart:math');
 
@@ -1337,6 +1342,7 @@ main() {
   math.loadLibrary(1 + 2);
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.EXTRA_POSITIONAL_ARGUMENTS, 65, 7),
     ]);
 
@@ -1769,6 +1775,7 @@ main() {
   math();
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 40, 4),
     ]);
     assertElement(findNode.simple('math()'), findElement.prefix('math'));
@@ -2332,14 +2339,16 @@ class MethodInvocationResolutionWithNullSafetyTest
 class A {}
 ''');
 
-    await assertNoErrorsInCode(r'''
+    await assertErrorsInCode(r'''
 // @dart = 2.7
 import 'a.dart' deferred as a;
 
 main() {
   a.loadLibrary();
 }
-''');
+''', [
+      error(HintCode.UNUSED_IMPORT, 22, 8),
+    ]);
 
     var import = findElement.importFind('package:test/a.dart');
 
diff --git a/pkg/analyzer/test/src/dart/resolution/prefixed_identifier_test.dart b/pkg/analyzer/test/src/dart/resolution/prefixed_identifier_test.dart
index ed75ddb8ff9..50f55276c98 100644
--- a/pkg/analyzer/test/src/dart/resolution/prefixed_identifier_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/prefixed_identifier_test.dart
@@ -278,14 +278,16 @@ class PrefixedIdentifierResolutionWithNullSafetyTest
 class A {}
 ''');
 
-    await assertNoErrorsInCode(r'''
+    await assertErrorsInCode(r'''
 // @dart = 2.7
 import 'a.dart' deferred as a;
 
 main() {
   a.loadLibrary;
 }
-''');
+''', [
+      error(HintCode.UNUSED_IMPORT, 22, 8),
+    ]);
 
     var import = findElement.importFind('package:test/a.dart');
 
diff --git a/pkg/analyzer/test/src/dart/resolution/type_name_test.dart b/pkg/analyzer/test/src/dart/resolution/type_name_test.dart
index 562aebb468c..60367803e15 100644
--- a/pkg/analyzer/test/src/dart/resolution/type_name_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/type_name_test.dart
@@ -197,6 +197,7 @@ main() {
   new math.A();
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.NEW_WITH_NON_TYPE, 49, 1),
     ]);
 
diff --git a/pkg/analyzer/test/src/diagnostics/const_with_non_type_test.dart b/pkg/analyzer/test/src/diagnostics/const_with_non_type_test.dart
index 67edb47e1f6..1f14038a4ef 100644
--- a/pkg/analyzer/test/src/diagnostics/const_with_non_type_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/const_with_non_type_test.dart
@@ -23,6 +23,7 @@ void f() {
   const lib.A();
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.CONST_WITH_NON_TYPE, 50, 1),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/extends_non_class_test.dart b/pkg/analyzer/test/src/diagnostics/extends_non_class_test.dart
index 53134417c5b..6f6cb916957 100644
--- a/pkg/analyzer/test/src/diagnostics/extends_non_class_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/extends_non_class_test.dart
@@ -118,6 +118,7 @@ import 'dart:math' as p;
 
 class C extends p.A {}
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.EXTENDS_NON_CLASS, 42, 3),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/invalid_null_aware_operator_test.dart b/pkg/analyzer/test/src/diagnostics/invalid_null_aware_operator_test.dart
index 8f903e52d84..2c89f6dd3bc 100644
--- a/pkg/analyzer/test/src/diagnostics/invalid_null_aware_operator_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/invalid_null_aware_operator_test.dart
@@ -260,6 +260,7 @@ f() {
   p?.x;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 8),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 31, 1),
     ]);
   }
@@ -471,6 +472,7 @@ f() {
   p?.x = 0;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 8),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 31, 1),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/mixin_of_non_class_test.dart b/pkg/analyzer/test/src/diagnostics/mixin_of_non_class_test.dart
index 948a8dd7bcf..dbc72faf3e7 100644
--- a/pkg/analyzer/test/src/diagnostics/mixin_of_non_class_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/mixin_of_non_class_test.dart
@@ -158,6 +158,7 @@ import 'dart:math' as p;
 
 class C with p.M {}
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.MIXIN_OF_NON_CLASS, 39, 3),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/prefix_identifier_not_followed_by_dot_test.dart b/pkg/analyzer/test/src/diagnostics/prefix_identifier_not_followed_by_dot_test.dart
index 4f0107370b8..686b88b3849 100644
--- a/pkg/analyzer/test/src/diagnostics/prefix_identifier_not_followed_by_dot_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/prefix_identifier_not_followed_by_dot_test.dart
@@ -27,6 +27,7 @@ class C {
   }
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 46, 1),
     ]);
   }
@@ -41,6 +42,7 @@ f() {
   p += 1;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 32, 1),
     ]);
   }
@@ -57,6 +59,7 @@ class C {
   }
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 46, 1),
     ]);
   }
@@ -90,6 +93,7 @@ f() {
   p = 1;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 32, 1),
     ]);
   }
@@ -104,6 +108,7 @@ f() {
   p += 1;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 32, 1),
     ]);
   }
@@ -133,6 +138,7 @@ f() {
   p?.loadLibrary();
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 41, 1),
     ]);
   }
@@ -148,6 +154,7 @@ f() {
   return p?.x;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 39, 1),
     ]);
   }
@@ -162,6 +169,7 @@ f() {
   return p?.loadLibrary;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 48, 1),
     ]);
   }
@@ -177,6 +185,7 @@ f() {
   p?.x = null;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 32, 1),
     ]);
   }
@@ -191,6 +200,7 @@ f() {
   p?.loadLibrary = null;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 41, 1),
     ]);
   }
@@ -205,6 +215,7 @@ f() {
   return p;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT, 39, 1),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/undefined_annotation_test.dart b/pkg/analyzer/test/src/diagnostics/undefined_annotation_test.dart
index 711ac5154cc..401219967a2 100644
--- a/pkg/analyzer/test/src/diagnostics/undefined_annotation_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/undefined_annotation_test.dart
@@ -52,6 +52,7 @@ import 'dart:math' as p;
 main() {
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.UNDEFINED_ANNOTATION, 25, 13),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/undefined_class_test.dart b/pkg/analyzer/test/src/diagnostics/undefined_class_test.dart
index 025eb5fb5df..7c35f6a96c6 100644
--- a/pkg/analyzer/test/src/diagnostics/undefined_class_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/undefined_class_test.dart
@@ -140,6 +140,7 @@ import 'dart:math' as p;
 
 p.A a;
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 11),
       error(CompileTimeErrorCode.UNDEFINED_CLASS, 26, 3),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/undefined_prefixed_name_test.dart b/pkg/analyzer/test/src/diagnostics/undefined_prefixed_name_test.dart
index 87cafbf1ad8..611ed5706af 100644
--- a/pkg/analyzer/test/src/diagnostics/undefined_prefixed_name_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/undefined_prefixed_name_test.dart
@@ -21,6 +21,7 @@ class UndefinedPrefixedNameTest extends PubPackageResolutionTest {
 import 'lib.dart' as p;
 f() => p.c;
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.UNDEFINED_PREFIXED_NAME, 33, 1),
     ]);
   }
@@ -33,6 +34,7 @@ f() {
   p.c = 0;
 }
 ''', [
+      error(HintCode.UNUSED_IMPORT, 7, 10),
       error(CompileTimeErrorCode.UNDEFINED_PREFIXED_NAME, 34, 1),
     ]);
   }
diff --git a/pkg/analyzer/test/src/diagnostics/unused_import_test.dart b/pkg/analyzer/test/src/diagnostics/unused_import_test.dart
index f574819f1c8..de780d7b76e 100644
--- a/pkg/analyzer/test/src/diagnostics/unused_import_test.dart
+++ b/pkg/analyzer/test/src/diagnostics/unused_import_test.dart
@@ -41,7 +41,6 @@ one.A a;
   }
 
   test_as_equalPrefixes_referenced() async {
-    // 18818
     newFile('$testPackageLibPath/lib1.dart', content: r'''
 class A {}
 ''');
@@ -56,9 +55,25 @@ one.B b;
 ''');
   }
 
-  @failingTest
+  test_as_equalPrefixes_referenced_via_export() async {
+    newFile('$testPackageLibPath/lib1.dart', content: r'''
+class A {}
+''');
+    newFile('$testPackageLibPath/lib2.dart', content: r'''
+class B {}
+''');
+    newFile('$testPackageLibPath/lib3.dart', content: r'''
+export 'lib2.dart';
+''');
+    await assertNoErrorsInCode(r'''
+import 'lib1.dart' as one;
+import 'lib3.dart' as one;
+one.A a;
+one.B b;
+''');
+  }
+
   test_as_equalPrefixes_unreferenced() async {
-    // See todo at ImportsVerifier.prefixElementMap.
     newFile('$testPackageLibPath/lib1.dart', content: r'''
 class A {}
 ''');
@@ -70,7 +85,59 @@ import 'lib1.dart' as one;
 import 'lib2.dart' as one;
 one.A a;
 ''', [
-      error(HintCode.UNUSED_IMPORT, 32, 11),
+      error(HintCode.UNUSED_IMPORT, 34, 11),
+    ]);
+  }
+
+  test_as_show_multipleElements() async {
+    newFile('$testPackageLibPath/lib1.dart', content: r'''
+class A {}
+class B {}
+''');
+    await assertNoErrorsInCode(r'''
+import 'lib1.dart' as one show A, B;
+one.A a = one.A();
+one.B b = one.B();
+''');
+  }
+
+  test_as_showTopLevelFunction() async {
+    newFile('$testPackageLibPath/lib1.dart', content: r'''
+class One {}
+topLevelFunction() {}
+''');
+    await assertErrorsInCode(r'''
+import 'lib1.dart' hide topLevelFunction;
+import 'lib1.dart' as one show topLevelFunction;
+class A {
+  static void x() {
+    One o;
+    one.topLevelFunction();
+  }
+}
+''', [
+      error(HintCode.UNUSED_LOCAL_VARIABLE, 129, 1),
+    ]);
+  }
+
+  test_as_showTopLevelFunction_multipleDirectives() async {
+    newFile('$testPackageLibPath/lib1.dart', content: r'''
+class One {}
+topLevelFunction() {}
+''');
+    await assertErrorsInCode(r'''
+import 'lib1.dart' hide topLevelFunction;
+import 'lib1.dart' as one show topLevelFunction;
+import 'lib1.dart' as two show topLevelFunction;
+class A {
+  static void x() {
+    One o;
+    one.topLevelFunction();
+    two.topLevelFunction();
+  }
+}
+''', [
+      error(HintCode.UNUSED_LOCAL_VARIABLE, 178, 1),
     ]);
   }
 
@@ -323,46 +390,6 @@ f() {
     ]);
   }
 
-  test_prefix_topLevelFunction() async {
-    newFile('$testPackageLibPath/lib1.dart', content: r'''
-class One {}
-topLevelFunction() {}
-''');
-    await assertErrorsInCode(r'''
-import 'lib1.dart' hide topLevelFunction;
-import 'lib1.dart' as one show topLevelFunction;
-class A {
-  static void x() {
-    One o;
-    one.topLevelFunction();
-  }
-}
-''', [
-      error(HintCode.UNUSED_LOCAL_VARIABLE, 129, 1),
-    ]);
-  }
-
-  test_prefix_topLevelFunction2() async {
-    newFile('$testPackageLibPath/lib1.dart', content: r'''
-class One {}
-topLevelFunction() {}
-''');
-    await assertErrorsInCode(r'''
-import 'lib1.dart' hide topLevelFunction;
-import 'lib1.dart' as one show topLevelFunction;
-import 'lib1.dart' as two show topLevelFunction;
-class A {
-  static void x() {
-    One o;
-    one.topLevelFunction();
-    two.topLevelFunction();
-  }
-}
-''', [
-      error(HintCode.UNUSED_LOCAL_VARIABLE, 178, 1),
-    ]);
-  }
-
   test_show() async {
     newFile('$testPackageLibPath/lib1.dart', content: r'''
 class A {}
diff --git a/pkg/analyzer/test/verify_diagnostics_test.dart b/pkg/analyzer/test/verify_diagnostics_test.dart
index af40e722b1e..b057f2706fa 100644
--- a/pkg/analyzer/test/verify_diagnostics_test.dart
+++ b/pkg/analyzer/test/verify_diagnostics_test.dart
@@ -49,6 +49,9 @@ class DocumentationValidator {
     // Need a way to make auxiliary files that (a) are not included in the
     // generated docs or (b) can be made persistent for fixes.
     'CompileTimeErrorCode.PART_OF_NON_PART',
+    // Need to avoid reporting an unused import with a prefix, when the prefix
+    // is only referenced in an invalid way.
+    'CompileTimeErrorCode.PREFIX_IDENTIFIER_NOT_FOLLOWED_BY_DOT',
     // Produces the diagnostic HintCode.UNUSED_LOCAL_VARIABLE when it shouldn't.
     'CompileTimeErrorCode.UNDEFINED_IDENTIFIER_AWAIT',
     // The code has been replaced but is not yet removed.
diff --git a/pkg/analyzer_cli/lib/src/build_mode.dart b/pkg/analyzer_cli/lib/src/build_mode.dart
index f022eeb1819..76679f51e57 100644
--- a/pkg/analyzer_cli/lib/src/build_mode.dart
+++ b/pkg/analyzer_cli/lib/src/build_mode.dart
@@ -30,7 +30,6 @@ import 'package:analyzer/src/summary/summary_sdk.dart' show SummaryBasedDartSdk;
 import 'package:analyzer/src/summary2/bundle_reader.dart';
 import 'package:analyzer/src/summary2/link.dart' as summary2;
 import 'package:analyzer/src/summary2/linked_element_factory.dart' as summary2;
-import 'package:analyzer/src/summary2/linked_library_context.dart' as summary2;
 import 'package:analyzer/src/summary2/package_bundle_format.dart';
 import 'package:analyzer/src/summary2/reference.dart' as summary2;
 import 'package:analyzer_cli/src/context_cache.dart';
diff --git a/pkg/analyzer_plugin/test/src/utilities/completion/completion_target_test.dart b/pkg/analyzer_plugin/test/src/utilities/completion/completion_target_test.dart
index 04ab568aa0a..f95ad22f91c 100644
--- a/pkg/analyzer_plugin/test/src/utilities/completion/completion_target_test.dart
+++ b/pkg/analyzer_plugin/test/src/utilities/completion/completion_target_test.dart
@@ -5,7 +5,6 @@
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart' as analyzer;
-import 'package:analyzer/src/generated/parser.dart' as analyzer;
 import 'package:analyzer/src/test_utilities/find_element.dart';
 import 'package:analyzer_plugin/src/utilities/completion/completion_target.dart';
 import 'package:test/test.dart';