refine when suggestions are limited to types

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,
@@ skipping 178 matching lines @@
     return node.parent.accept(this);
   }
 
   @override
   _ImportedSuggestionBuilder visitStringLiteral(StringLiteral node) {
     return null;
   }
 
   @override
   _ImportedSuggestionBuilder visitTypeName(TypeName node) {
-    return new _ImportedSuggestionBuilder(request, typesOnly: true);
+    bool typesOnly = false;
+    // If suggesting completions within a TypeName node
+    // then limit suggestions to only types in specific situations
+    AstNode p = node.parent;
+    if (p is IsExpression || p is ConstructorName || p is AsExpression) {
+      typesOnly = true;
+    } else if (p is VariableDeclarationList) {
+      // TODO (danrubel) When entering 1st of 2 identifiers on assignment LHS
+      // the user may be either (1) entering a type for the assignment
+      // or (2) starting a new statement.
+      // Consider suggesting only types
+      // if only spaces separates the 1st and 2nd identifiers.
+    }
+    return new _ImportedSuggestionBuilder(request, typesOnly: typesOnly);
   }
 
   @override
   _ImportedSuggestionBuilder
       visitVariableDeclaration(VariableDeclaration node) {
     Token equals = node.equals;
     // Make suggestions for the RHS of a variable declaration
     if (equals != null && request.offset >= equals.end) {
       return new _ImportedSuggestionBuilder(request, excludeVoidReturn: true);
     }
@@ skipping 142 matching lines @@
     addFilteredSuggestions(cache.importedTypeSuggestions);
     addFilteredSuggestions(cache.libraryPrefixSuggestions);
     if (!typesOnly) {
       addFilteredSuggestions(cache.otherImportedSuggestions);
       if (!excludeVoidReturn) {
         addFilteredSuggestions(cache.importedVoidReturnSuggestions);
       }
     }
   }
 }