Cannot generate java-compatible abstract varargs method #10658
Description
I need to generate a java-compatible varargs method in an interface in order to access a JNA native method (which relies on the varargs signature). This appears to still be an issue in 2.12.4, despite some other similar issues (such as #1459) listing this as having been fixed.
10:12 scl$ scalac -version
Scala compiler version 2.12.4 -- Copyright 2002-2017, LAMP/EPFL and Lightbend, Inc.
10:12 scl$ cat Vargs.scala
trait Vargs {
@scala.annotation.varargs def varg(args: AnyRef*): Unit
def noop(): Unit
}
10:12 scl$ scalac Vargs.scala
10:16 scl$ javap Vargs.class
Compiled from "Vargs.scala"
public interface Vargs {
public static void varg$(Vargs, java.lang.Object...);
public void varg(java.lang.Object...);
public abstract void varg(scala.collection.Seq<java.lang.Object>);
public abstract void noop();
}
10:12 scl$ cat VargsImpl.java
public class VargsImpl implements Vargs {
public void noop() {
}
public void varg(java.lang.Object... args) {
System.out.println("varg, matey!");
}
}
10:12 scl$ javac -cp . VargsImpl.java
An exception has occurred in the compiler (1.8.0_151). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.NullPointerException
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitIdent(Flow.java:2403)
at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:2011)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:404)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scan(Flow.java:1382)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scanExpr(Flow.java:1635)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitApply(Flow.java:2258)
at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1465)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:404)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scan(Flow.java:1382)
at com.sun.tools.javac.tree.TreeScanner.visitExec(TreeScanner.java:175)
at com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1296)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:404)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scan(Flow.java:1382)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:57)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitBlock(Flow.java:1883)
at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:909)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:404)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scan(Flow.java:1382)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitMethodDef(Flow.java:1811)
at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:778)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:404)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scan(Flow.java:1382)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitClassDef(Flow.java:1749)
at com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:693)
at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:404)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.scan(Flow.java:1382)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.analyzeTree(Flow.java:2446)
at com.sun.tools.javac.comp.Flow$AssignAnalyzer.analyzeTree(Flow.java:2429)
at com.sun.tools.javac.comp.Flow.analyzeTree(Flow.java:211)
at com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1327)
at com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1296)
at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:901)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:860)
at com.sun.tools.javac.main.Main.compile(Main.java:523)
at com.sun.tools.javac.main.Main.compile(Main.java:381)
at com.sun.tools.javac.main.Main.compile(Main.java:370)
at com.sun.tools.javac.main.Main.compile(Main.java:361)
at com.sun.tools.javac.Main.compile(Main.java:56)
at com.sun.tools.javac.Main.main(Main.java:42)