Fix for NPE with StringLiteral in toString()

compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java

 // Copyright (c) 2012, 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.
 
 package com.google.dart.compiler.parser;
 
 import com.google.common.base.Joiner;
 import com.google.dart.compiler.DartCompilerListener;
 import com.google.dart.compiler.DartSourceTest;
 import com.google.dart.compiler.ast.DartAnnotation;
 import com.google.dart.compiler.ast.DartArrayLiteral;
 import com.google.dart.compiler.ast.DartAssertStatement;
 import com.google.dart.compiler.ast.DartBinaryExpression;
 import com.google.dart.compiler.ast.DartBooleanLiteral;
 import com.google.dart.compiler.ast.DartClass;
 import com.google.dart.compiler.ast.DartComment;
 import com.google.dart.compiler.ast.DartExprStmt;
 import com.google.dart.compiler.ast.DartExpression;
 import com.google.dart.compiler.ast.DartField;
 import com.google.dart.compiler.ast.DartFieldDefinition;
 import com.google.dart.compiler.ast.DartFunctionExpression;
 import com.google.dart.compiler.ast.DartIdentifier;
+import com.google.dart.compiler.ast.DartImportDirective;
 import com.google.dart.compiler.ast.DartIntegerLiteral;
 import com.google.dart.compiler.ast.DartMapLiteral;
 import com.google.dart.compiler.ast.DartMethodDefinition;
 import com.google.dart.compiler.ast.DartNode;
 import com.google.dart.compiler.ast.DartParameter;
 import com.google.dart.compiler.ast.DartPropertyAccess;
 import com.google.dart.compiler.ast.DartStatement;
 import com.google.dart.compiler.ast.DartStringInterpolation;
 import com.google.dart.compiler.ast.DartStringLiteral;
 import com.google.dart.compiler.ast.DartTryStatement;
@@ skipping 12 matching lines @@
         "library lib;",
         "export 'a.dart' show A, B hide C, D;"));
   }
 
   public void test_exportDirective_noCombinators() {
     parseUnit("test.dart", Joiner.on("\n").join(
         "library lib;",
         "export 'a.dart';"));
   }
 
+  public void test_importDirective_noUri() {
+    DartUnit unit = parseUnit("test.dart", Joiner.on("\n").join(
+        "library lib;",
+        "import;"),
+        ParserErrorCode.EXPECTED_TOKEN, 2, 7);
+    DartImportDirective dir = (DartImportDirective) unit.getDirectives().get(1);
+    System.out.println(dir.toSource());
+  }
+
   public void test_getter() {
     parseUnit("getter.dart", Joiner.on("\n").join(
         "class G {",
         "  // Old getter syntax",
         "  int get g1() => 1;",
         "  // New getter syntax",
         "  int get g2 => 2;",
         "}"));
   }
 
@@ skipping 1499 matching lines @@
             "typedef func(var arg());",
             ParserErrorCode.FUNCTION_TYPED_PARAMETER_IS_VAR, 1, 18);
   }
 
   public void test_finalInFunctionType() throws Exception {
     parseUnit("phony_var_in_function_type.dart",
             "typedef func(final arg());",
             ParserErrorCode.FUNCTION_TYPED_PARAMETER_IS_FINAL, 1, 20);
   }
 }