javac throws a NPE when compiling a lambda expression
Maurizio Cimadamore
maurizio.cimadamore at oracle.com
Mon Jun 13 03:41:14 PDT 2011
On 13/06/11 11:37, Ali Ebrahimi wrote:
> Hi Maurizio,
> similar crash for this code:
> call(#{ -> System.out.println(
> undefinedVar ); });
Yeah, all these problems have gone now (fixed in the latest push).
Thanks for the headsup.
Maurizio
> Ali Ebrahimi
>
> On Mon, Jun 13, 2011 at 12:07 PM, Maurizio Cimadamore
> <maurizio.cimadamore at oracle.com
> <mailto: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 <mailto: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
>
>
>
>
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