javac throws a NPE when compiling a lambda expression

[Ali Ebrahimi]

Hi,
yes i had import statement. by removing that crash occurs.

Ali Ebrahimi

On Mon, Jun 13, 2011 at 12:07 PM, Maurizio Cimadamore <
maurizio.cimadamore at oracle.com> wrote:

> I confirm that the following simplified example actually fails with the
> latest compiler:
>
> class TestLambda {
>
>
>  interface SAM {
>    void m();
>  }
>
>  {
>    call(#{ -> log(new Date() + "");  });
>  }
>
>  void call(SAM s) { }
>
>
>  void log(String msg) {
>    System.out.println(msg);
>  }
>  }
>
> The problem is caused by a bad error recovery - in the above example
> java.util.Date cannot be found, because the corresponding import is missing.
> Which means that the compiler should emit an error, but in this case the
> error is swallen when attributing the lambda body - which means that the
> compiler tries to emit code for an incorrect source program - hence the NPE.
>
> Maurizio
>
>
>
> On 13/06/11 07:46, Ali Ebrahimi wrote:
>
>> Hi,
>> This sample code compiles with current lambda repository build.
>>
>> Ali Ebrahimi
>>
>> On Sat, Jun 11, 2011 at 9:00 AM, Arul Dhesiaseelan<aruld at acm.org>  wrote:
>>
>>  public class TestLambda {
>>>
>>>  class Payment {
>>>    private int amount;
>>>
>>>    Payment(int amount) {
>>>      this.amount = amount;
>>>    }
>>>
>>>    public int getAmount() {
>>>      return amount;
>>>    }
>>>  }
>>>
>>>  interface PaymentProcessor {
>>>    void process(Payment pmt);
>>>  }
>>>
>>>  {
>>>    invokeProcessor(# { pmt ->  log("Processed # " + pmt.getAmount() + "
>>> at
>>> " + new Date()) });
>>>  }
>>>
>>>  void invokeProcessor(PaymentProcessor processor) {
>>>    processor.process(new Payment(42));
>>>  }
>>>
>>>  void log(String msg) {
>>>    System.out.println(msg);
>>>  }
>>> }
>>>
>>> I am trying to rebuild my old Lambda example (which used to work with
>>> earlier prototype using build 115), but failed to compile with the latest
>>> prototype using build 145:
>>>
>>> An exception has occurred in the compiler (1.7.0-internal). Please file a
>>> bug at the Java Developer Connection (
>>> http://java.sun.com/webapps/bugreport)
>>> after checking the Bug Parade for duplicates. Include your program and
>>> the
>>> following diagnostic in your report.  Thank you.
>>> java.lang.NullPointerException
>>>        at com.sun.tools.javac.comp.Flow.visitNewClass(Flow.java:1308)
>>>        at
>>> com.sun.tools.javac.tree.JCTree$JCNewClass.accept(JCTree.java:1391)
>>>        at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
>>>        at com.sun.tools.javac.comp.Flow.scanExpr(Flow.java:572)
>>>        at com.sun.tools.javac.comp.Flow.visitBinary(Flow.java:1504)
>>>        at
>>> com.sun.tools.javac.tree.JCTree$JCBinary.accept(JCTree.java:1654)
>>>        at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
>>>        at com.sun.tools.javac.comp.Flow.scanExpr(Flow.java:572)
>>>        at com.sun.tools.javac.comp.Flow.scanExprs(Flow.java:582)
>>>        at com.sun.tools.javac.comp.Flow.visitApply(Flow.java:1299)
>>>        at
>>>
>>> com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1337)
>>>        at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
>>>        at com.sun.tools.javac.comp.Flow.scanStat(Flow.java:556)
>>>        at com.sun.tools.javac.comp.Flow.analyzeLambda(Flow.java:1370)
>>>        at com.sun.tools.javac.comp.Attr.attribLambda(Attr.java:2314)
>>>        at com.sun.tools.javac.comp.Attr$1.deferredAttr(Attr.java:2194)
>>>        at com.sun.tools.javac.comp.Attr$1.deferredAttr(Attr.java:2185)
>>>        at
>>>
>>>
>>> com.sun.tools.javac.comp.Attr$SAMDeferredAttribution.complete(Attr.java:2793)
>>>        at
>>>
>>> com.sun.tools.javac.comp.Infer$InferPolyCompleter.complete(Infer.java:737)
>>>        at com.sun.tools.javac.comp.Infer.instantiatePoly(Infer.java:748)
>>>        at
>>>
>>>
>>> com.sun.tools.javac.comp.Resolve.checkRawArgumentsAcceptable(Resolve.java:553)
>>>        at
>>> com.sun.tools.javac.comp.Infer.instantiateMethod(Infer.java:419)
>>>        at
>>> com.sun.tools.javac.comp.Resolve.rawInstantiate(Resolve.java:396)
>>>        at com.sun.tools.javac.comp.Resolve.selectBest(Resolve.java:820)
>>>        at com.sun.tools.javac.comp.Resolve.findMethod(Resolve.java:1064)
>>>        at com.sun.tools.javac.comp.Resolve.findMethod(Resolve.java:1025)
>>>        at com.sun.tools.javac.comp.Resolve.findFun(Resolve.java:1158)
>>>        at
>>> com.sun.tools.javac.comp.Resolve.resolveMethod(Resolve.java:1582)
>>>        at com.sun.tools.javac.comp.Attr.visitIdent(Attr.java:2546)
>>>        at
>>> com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:1826)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:466)
>>>        at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1578)
>>>        at
>>>
>>> com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1337)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:466)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:484)
>>>        at com.sun.tools.javac.comp.Attr.attribExpr(Attr.java:499)
>>>        at com.sun.tools.javac.comp.Attr.visitExec(Attr.java:1334)
>>>        at
>>>
>>>
>>> com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1180)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:466)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:484)
>>>        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:519)
>>>        at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:535)
>>>        at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:952)
>>>        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:794)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:466)
>>>        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:484)
>>>        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:519)
>>>        at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:3793)
>>>        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3715)
>>>        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:3651)
>>>        at com.sun.tools.javac.comp.Attr.attrib(Attr.java:3625)
>>>        at
>>> com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1189)
>>>        at
>>> com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:877)
>>>        at
>>> com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:836)
>>>        at com.sun.tools.javac.main.Main.compile(Main.java:417)
>>>        at com.sun.tools.javac.main.Main.compile(Main.java:331)
>>>        at com.sun.tools.javac.main.Main.compile(Main.java:322)
>>>        at com.sun.tools.javac.Main.compile(Main.java:76)
>>>        at com.sun.tools.javac.Main.main(Main.java:61)
>>>
>>>
>>> java version "1.7.0-ea"
>>> Java(TM) SE Runtime Environment (build 1.7.0-ea-b145)
>>> Java HotSpot(TM) 64-Bit Server VM (build 21.0-b15, mixed mode)
>>>
>>> I am not sure what has changed since then. Any clues?
>>>
>>> -Arul
>>>
>>>
>>>
>