Fix summary handling of unresolved imports, exports, and parts.

pkg/analyzer/lib/src/summary/index_unit.dart

 // Copyright (c) 2016, 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.
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/member.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:analyzer/src/summary/format.dart';
 import 'package:analyzer/src/summary/idl.dart';
 
 /**
  * Information about an element that is actually put into index for some other
  * related element. For example for a synthetic getter this is the corresponding
  * non-synthetic field and [IndexSyntheticElementKind.getter] as the [kind].
  */
 class IndexElementInfo {
   final Element element;
   final IndexSyntheticElementKind kind;
 
   factory IndexElementInfo(Element element) {
     IndexSyntheticElementKind kind = IndexSyntheticElementKind.notSynthetic;
-    if (element.isSynthetic) {
+    if (element is LibraryElement || element is CompilationUnitElement) {
+      kind = IndexSyntheticElementKind.unit;
+    } else if (element.isSynthetic) {
       if (element is ConstructorElement) {
         kind = IndexSyntheticElementKind.constructor;
         element = element.enclosingElement;
       } else if (element is FunctionElement && element.name == 'loadLibrary') {
         kind = IndexSyntheticElementKind.loadLibrary;
         element = element.library;
       } else if (element is FieldElement) {
         FieldElement field = element;
         kind = IndexSyntheticElementKind.field;
         element = field.getter;
@@ skipping 16 matching lines @@
         }
       } else if (element is TopLevelVariableElement) {
         TopLevelVariableElement property = element;
         kind = IndexSyntheticElementKind.topLevelVariable;
         element = property.getter;
         element ??= property.setter;
       } else {
         throw new ArgumentError(
             'Unsupported synthetic element ${element.runtimeType}');
       }
-    } else if (element is LibraryElement || element is CompilationUnitElement) {
-      kind = IndexSyntheticElementKind.unit;
     }
     return new IndexElementInfo._(element, kind);
   }
 
   IndexElementInfo._(this.element, this.kind);
 }
 
 /**
  * Object that gathers information about the whole package index and then uses
  * it to assemble a new [PackageIndexBuilder].  Call [indexUnit] on each
@@ skipping 824 matching lines @@
         usedNameOffsets: nameRelations.map((r) => r.offset).toList(),
         usedNameIsQualifiedFlags:
             nameRelations.map((r) => r.isQualified).toList());
   }
 
   void defineName(String name, IndexNameKind kind, int offset) {
     _StringInfo nameInfo = pkg._getStringInfo(name);
     definedNames.add(new _DefinedNameInfo(nameInfo, kind, offset));
   }
 }