javac throws a NPE when compiling a lambda expression

[Ali Ebrahimi]

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
>
>