Fix the length of this expression nodes (issue 5185)

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

Index: compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java
===================================================================
--- compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java	(revision 12443)
+++ compiler/javatests/com/google/dart/compiler/parser/SyntaxTest.java	(working copy)
@@ -22,6 +22,7 @@
 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;
@@ -1428,6 +1429,21 @@
             ParserErrorCode.FOR_IN_WITH_MULTIPLE_VARIABLES, 2, 17);
   }
 
+  public void test_formalParameters_field() throws Exception {
+    DartUnit unit = parseUnit("formalParameters.dart",
+        Joiner.on("\n").join(
+            "class A {",
+            "  final foo;",
+            "  A(this.foo) {}",
+            "}"));
+    DartClass classNode = (DartClass) unit.getTopLevelNodes().get(0);
+    DartMethodDefinition methodNode = (DartMethodDefinition) classNode.getMembers().get(1);
+    DartParameter parameterNode = methodNode.getFunction().getParameters().get(0);
+    assertTrue(parameterNode.getName() instanceof DartPropertyAccess);
+    DartPropertyAccess accessNode = (DartPropertyAccess) parameterNode.getName();
+    assertEquals(4, accessNode.getQualifier().getSourceInfo().getLength());
+  }
+
   public void test_formalParameters_named() throws Exception {
     parseUnit("formalParameters.dart",
         Joiner.on("\n").join(