When target requires a function, propose a function reference, not an invocation

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

 // Copyright (c) 2014, 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.computer.dart.toplevel;
 
 import 'dart:async';
 import 'dart:collection';
 
 import 'package:analysis_server/src/protocol_server.dart'
     hide Element, ElementKind;
 import 'package:analysis_server/src/services/completion/dart_completion_cache.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analysis_server/src/services/completion/optype.dart';
 import 'package:analysis_server/src/services/completion/suggestion_builder.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 
 /**
  * A computer for calculating imported class and top level variable
  * `completion.getSuggestions` request results.
  */
 class ImportedComputer extends DartCompletionComputer {
   bool shouldWaitForLowPrioritySuggestions;
+  bool suggestionsComputed;
   _ImportedSuggestionBuilder builder;
 
   ImportedComputer({this.shouldWaitForLowPrioritySuggestions: false});
 
   @override
   bool computeFast(DartCompletionRequest request) {
     OpType optype = request.optype;
     if (optype.includeTopLevelSuggestions ||
         optype.includeConstructorSuggestions) {
       builder = new _ImportedSuggestionBuilder(request,
           typesOnly: optype.includeOnlyTypeNameSuggestions,
           excludeVoidReturn: !optype.includeVoidReturnSuggestions,
           constructorsOnly: optype.includeConstructorSuggestions);
       builder.shouldWaitForLowPrioritySuggestions =
           shouldWaitForLowPrioritySuggestions;
-      return builder.computeFast(request.node);
+      // If target is an argument in an argument list
+      // then suggestions may need to be adjusted
+      suggestionsComputed = builder.computeFast(request.node);
+      return suggestionsComputed && request.target.argIndex == null;
     }
     return true;
   }
 
   @override
   Future<bool> computeFull(DartCompletionRequest request) {
     if (builder != null) {
-      return builder.computeFull(request.node);
+      if (!suggestionsComputed) {
+        return builder.computeFull(request.node).then((bool result) {
+          _updateSuggestions(request);
+          return result;
+        });
+      }
+      _updateSuggestions(request);
+      return new Future.value(true);
     }
     return new Future.value(false);
   }
+
+  /**
+   * If target is a function argument, suggest identifiers not invocations
+   */
+  void _updateSuggestions(DartCompletionRequest request) {
+    if (request.target.isFunctionalArgument()) {
+      request.convertInvocationsToIdentifiers();
+    }
+  }
 }
 
 /**
  * [_ImportedSuggestionBuilder] traverses the imports and builds suggestions
  * based upon imported elements.
  */
 class _ImportedSuggestionBuilder extends ElementSuggestionBuilder
     implements SuggestionBuilder {
   bool shouldWaitForLowPrioritySuggestions;
   final DartCompletionRequest request;
@@ skipping 171 matching lines @@
     _addFilteredSuggestions(filterText, cache.libraryPrefixSuggestions);
     if (!typesOnly) {
       _addFilteredSuggestions(filterText, cache.otherImportedSuggestions);
       if (!excludeVoidReturn) {
         _addFilteredSuggestions(
             filterText, cache.importedVoidReturnSuggestions);
       }
     }
   }
 }