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  1. JDK
  2. JDK-8144974

Uncompilable method references to constructors when using generics

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    • Icon: Bug Bug
    • Resolution: Duplicate
    • Icon: P4 P4
    • None
    • 8u11
    • tools
    • x86
    • windows_8

      FULL PRODUCT VERSION :
      java version "1.8.0_60"
      Java(TM) SE Runtime Environment (build 1.8.0_60-b27)
      Java HotSpot(TM) 64-Bit Server VM (build 25.60-b23, mixed mode)

      ADDITIONAL OS VERSION INFORMATION :
      Microsoft Windows [Version 10.0.10240]

      EXTRA RELEVANT SYSTEM CONFIGURATION :
      Netbeans 8.0.2

      A DESCRIPTION OF THE PROBLEM :
      (Appears to be a problem on Netbeans only, eclipse appears unaffected)

      Given a method that takes two Suppliers, both of similar but different Generics themselves (e.g. both Suppliers of List, but the List of two distinct types); calling the method using method references to the a constructor of a single class implementing List will result in the compiler failing.

      Tested versions:
      32-bit: 8u66
      64-bit: 8u45, 8u60, 8u66

      Tested on Microsoft Windows [Version 6.1.7601], Eclipse Luna 4.4.0, 32-bit 8u45 and 8u66 and was unable to reproduce the error.

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      EXPECTED -
      Valid compilation.
      ACTUAL -
      Compilation fails with the following exception

      ERROR MESSAGES/STACK TRACES THAT OCCUR :
      An exception has occurred in the compiler (1.8.0_11). 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$AbstractAssignAnalyzer.visitIdent(Flow.java:2327)
      at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:2005)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.tree.TreeScanner.visitReference(TreeScanner.java:268)
      at com.sun.tools.javac.tree.JCTree$JCMemberReference.accept(JCTree.java:1967)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scanExpr(Flow.java:1596)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scanExprs(Flow.java:1608)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.visitApply(Flow.java:2205)
      at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1459)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.tree.TreeScanner.visitExec(TreeScanner.java:175)
      at com.sun.tools.javac.tree.JCTree$JCExpressionStatement.accept(JCTree.java:1290)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:57)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.visitBlock(Flow.java:1815)
      at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:903)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.visitMethodDef(Flow.java:1753)
      at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitMethodDef(Flow.java:2507)
      at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:772)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.visitClassDef(Flow.java:1705)
      at com.sun.tools.javac.comp.Flow$AssignAnalyzer.visitClassDef(Flow.java:2486)
      at com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:687)
      at com.sun.tools.javac.tree.TreeScanner.scan(TreeScanner.java:49)
      at com.sun.tools.javac.comp.Flow$BaseAnalyzer.scan(Flow.java:389)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.scan(Flow.java:1367)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.analyzeTree(Flow.java:2370)
      at com.sun.tools.javac.comp.Flow$AbstractAssignAnalyzer.analyzeTree(Flow.java:2353)
      at com.sun.tools.javac.comp.Flow.analyzeTree(Flow.java:210)
      at com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1325)
      at com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1299)
      at com.sun.tools.javac.main.JavaCompiler.compile2(JavaCompiler.java:904)
      at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:863)
      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 sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:483)
      at org.apache.tools.ant.taskdefs.compilers.Javac13.execute(Javac13.java:56)
      at org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:1159)
      at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:935)
      at org.netbeans.modules.java.source.ant.JavacTask.execute(JavacTask.java:145)
      at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
      at sun.reflect.GeneratedMethodAccessor204.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:483)
      at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
      at org.apache.tools.ant.Task.perform(Task.java:348)
      at org.apache.tools.ant.taskdefs.Sequential.execute(Sequential.java:68)
      at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
      at sun.reflect.GeneratedMethodAccessor204.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:483)
      at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
      at org.apache.tools.ant.Task.perform(Task.java:348)
      at org.apache.tools.ant.taskdefs.MacroInstance.execute(MacroInstance.java:396)
      at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:292)
      at sun.reflect.GeneratedMethodAccessor204.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
      at java.lang.reflect.Method.invoke(Method.java:483)
      at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
      at org.apache.tools.ant.Task.perform(Task.java:348)
      at org.apache.tools.ant.Target.execute(Target.java:435)
      at org.apache.tools.ant.Target.performTasks(Target.java:456)
      at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1393)
      at org.apache.tools.ant.Project.executeTarget(Project.java:1364)
      at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
      at org.apache.tools.ant.Project.executeTargets(Project.java:1248)
      at org.apache.tools.ant.module.bridge.impl.BridgeImpl.run(BridgeImpl.java:286)
      at org.apache.tools.ant.module.run.TargetExecutor.run(TargetExecutor.java:555)
      at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:153)

      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      import java.util.List;
      import java.util.function.Supplier;

      public class SubClass extends SuperClass<Integer, String> {

          public SubClass() {
              super(ArrayList::new, ArrayList::new);
      // super(ArrayList<A>::new, LinkedList<B>::new); // Also fails to compile...
          }

      }

      class SuperClass<A,B> {
          
          public SuperClass(Supplier<List<A>> supA, Supplier<List<B>> supB) {
              supA.get();
              supB.get();
          }

      }
      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      Using the () -> {} notation compiles correctly.

            fmatte Fairoz Matte
            webbuggrp Webbug Group
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              Created:
              Updated:
              Resolved: