javac throwing NPE at com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitApply

[Filipp Zhinkin]

Hi,

I've found that following code force javac to throw NullPointerException:

public class NPE {
     public static void main(String args[]) {
         // "cannot find symbol" error is expected
         new Integer(0).forEach(System.out::println);
     }
}

$java -version
openjdk version "1.8.0-ea"
OpenJDK Runtime Environment (build 
1.8.0-ea-lambda-nightly-h1745-20121105-b64-b00)
OpenJDK Server VM (build 25.0-b05, mixed mode)

$javac NPE.java
An exception has occurred in the compiler (1.8.0-ea). Please file a bug 
at the Java Developer Connection 
(http://java.sun.com/webapps/bugreport)  after checking the Bug Parade 
for duplicates. Include your program and the following diagnostic in 
your report.  Thank you.
java.lang.NullPointerException
     at 
com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitApply(Flow.java:1197)
     at 
com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1395)
     at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
     at com.sun.tools.javac.tree.TreeScanner.visitExec(TreeScanner.java:173)
     at 
com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1226)
     at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
     at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:57)
     at com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitBlock(Flow.java:960)
     at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:839)
     at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
     at 
com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitMethodDef(Flow.java:927)
     at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:723)
     at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
     at 
com.sun.tools.javac.comp.Flow$FlowAnalyzer.visitClassDef(Flow.java:890)
     at com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:645)
     at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
     at 
com.sun.tools.javac.comp.Flow$FlowAnalyzer.analyzeTree(Flow.java:1277)
     at 
com.sun.tools.javac.comp.Flow$FlowAnalyzer.analyzeTree(Flow.java:1267)
     at com.sun.tools.javac.comp.Flow.analyzeTree(Flow.java:210)
     at com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1297)
     at com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1271)
     at 
com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:911)
     at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:870)
     at com.sun.tools.javac.main.Main.compile(Main.java:441)
     at com.sun.tools.javac.main.Main.compile(Main.java:358)
     at com.sun.tools.javac.main.Main.compile(Main.java:347)
     at com.sun.tools.javac.main.Main.compile(Main.java:338)
     at com.sun.tools.javac.Main.compile(Main.java:76)
     at com.sun.tools.javac.Main.main(Main.java:61)


With method reference replaced by lambda expression javac will report 
semantic error as expected:

public class SemError {
     public static void main(String args[]) {
         new Integer(0).forEach((x) -> { System.out.println(x); });
     }
}

$javac SemError.java
SemError.java:3: error: cannot find symbol
         new Integer(0).forEach((x) -> { System.out.println(x); });
                       ^
   symbol:   method forEach(<none>)
   location: class Integer
1 error

Hope it will be useful.

Filipp.