fix assignment with this

Test/TestParser.hs

@@ -206,7 +206,10 @@ testExpressionConstructorCall = TestCase $
 
 testExpresssionExternalMethodCall = TestCase $
     assertEqual "expect method call on sub" (StatementExpressionExpression (MethodCall (Reference "Obj") "foo" [])) $
-    parseExpression [IDENTIFIER "Obj",IDENTIFIER "foo",LBRACE,RBRACE]
+    parseExpression [IDENTIFIER "Obj",DOT,IDENTIFIER "foo",LBRACE,RBRACE]
+testExpressionAssignWithThis = TestCase $
+    assertEqual "expect assignment on Field" (StatementExpressionExpression (Assignment (BinaryOperation NameResolution (Reference "this") (Reference "x")) (Reference "y"))) $
+    parseExpression [THIS,DOT,IDENTIFIER "x",ASSIGN,IDENTIFIER "y"]
 
 testStatementIfThen = TestCase $
     assertEqual "expect empty ifthen" [If (Reference "a") (Block [Block []]) Nothing] $
@@ -296,6 +299,8 @@ tests = TestList [
     testExpressionSimpleFieldAccess,
     testExpressionFieldSubAccess,
     testExpressionConstructorCall,
+    testExpresssionExternalMethodCall,
+    testExpressionAssignWithThis,
     testStatementIfThen,
     testStatementIfThenElse,
     testStatementWhile,

src/Parser/JavaParser.y

@@ -265,6 +265,7 @@ conditionalorexpression : conditionalandexpression { $1 }
                 --  | conditionalorexpression LOGICALOR conditionalandexpression{ }
 
 lefthandside     : name { $1 }
+                 | primary { $1 }
 
 assignmentoperator : ASSIGN { Nothing }
                  | TIMESEQUAL { Just Multiplication }