Issue 26096. Explicitly compute the result that ensures that directives are resolved in units.

pkg/analysis_server/lib/src/services/completion/dart/completion_manager.dart

 // Copyright (c) 2015, 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 services.completion.dart.manager;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/provisional/completion/completion_core.dart'
@@ skipping 281 matching lines @@
     }
     LibraryElement libElem = libraryElement;
     if (libElem == null) {
       return null;
     }
     _resolvedUnits = <CompilationUnitElement>[];
     for (CompilationUnitElement unresolvedUnit in libElem.units) {
       CompilationUnit unit = await _computeAsync(
           this,
           new LibrarySpecificUnit(libElem.source, unresolvedUnit.source),
-          RESOLVED_UNIT3,
+          RESOLVED_UNIT4,
           performance,
           'resolve library unit');
       checkAborted();
       CompilationUnitElement resolvedUnit = unit?.element;
       if (resolvedUnit != null) {
         _resolvedUnits.add(resolvedUnit);
       }
     }
     return _resolvedUnits;
   }
@@ skipping 56 matching lines @@
       }
     } else {
       libSource = source;
     }
 
     // Most (all?) contributors need declarations in scope to be resolved
     if (libSource != null) {
       unit = await _computeAsync(
           request,
           new LibrarySpecificUnit(libSource, source),
-          resultDescriptor ?? RESOLVED_UNIT3,
+          resultDescriptor ?? RESOLVED_UNIT4,
           performance,
           'resolve declarations');
     }
 
     DartCompletionRequestImpl dartRequest = new DartCompletionRequestImpl._(
         request.context,
         request.resourceProvider,
         request.searchEngine,
         libSource,
         request.source,
@@ skipping 94 matching lines @@
               // Replacement range for import URI
               return new ReplacementRange(start, end - start);
             }
           }
         }
       }
     }
     return new ReplacementRange(requestOffset, 0);
   }
 }