Fix LUB computation in face of errors in code (issue 26631)

pkg/analyzer/lib/src/generated/static_type_analyzer.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 analyzer.src.generated.static_type_analyzer;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 644 matching lines @@
           contextType.element == _typeProvider.listType.element) {
         _resolver.inferenceContext.recordInference(node, contextType);
         _recordStaticType(node, contextType);
         return null;
       }
 
       // If we don't have a type from the context, try to infer from the
       // elements
       if (node.elements.isNotEmpty) {
         // Infer the list type from the arguments.
-        DartType staticType =
-            node.elements.map((e) => e.staticType).reduce(_leastUpperBound);
+        Iterable<DartType> types = node.elements.map((e) => e.staticType).where((t) => t != null);
+        if (types.isEmpty) {
+          return null;
+        }
+        DartType staticType = types.reduce(_leastUpperBound);
         if (staticType.isBottom) {
           staticType = _dynamicType;
         }
         DartType listLiteralType =
             _typeProvider.listType.instantiate(<DartType>[staticType]);
         if (!staticType.isDynamic) {
           _resolver.inferenceContext.recordInference(node, listLiteralType);
         }
         _recordStaticType(node, listLiteralType);
         return null;
@@ skipping 1596 matching lines @@
     }
     // merge types
     if (result == null) {
       result = type;
     } else {
       result = _typeSystem.getLeastUpperBound(_typeProvider, result, type);
     }
     return null;
   }
 }