Issue 17024. Quick Fix to find imported library.

pkg/analysis_server/lib/src/services/correction/assist_internal.dart

Index: pkg/analysis_server/lib/src/services/correction/assist_internal.dart
diff --git a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
index 186c47888242ca59b203c5218d6e3bb40eacbc94..9cc5675cb7681f727b50d30b3cb7d7f47eab0b32 100644
--- a/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
+++ b/pkg/analysis_server/lib/src/services/correction/assist_internal.dart
@@ -524,6 +524,10 @@ class AssistProcessor {
     }
     // prepare whole import namespace
     ImportElement importElement = importDirective.element;
+    if (importElement == null) {
+      _coverageMarker();
+      return;
+    }
     Map<String, Element> namespace = getImportNamespace(importElement);
     // prepare names of referenced elements (from this import)
     SplayTreeSet<String> referencedNames = new SplayTreeSet<String>();