FULL PRODUCT VERSION :


A DESCRIPTION OF THE PROBLEM :
Compiling the two attached trivial classes leads to the following compiler-failure:

An exception has occurred in the compiler (1.8.0_91). 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.AssertionError: isSubClass C
        at com.sun.tools.javac.code.Symbol.isSubClass(Symbol.java:447)
        at com.sun.tools.javac.code.Symbol.isMemberOf(Symbol.java:456)

Reproduced with the java-versions 1.8.0_102, 1.8.0_101, 1.8.0_91, 1.8.0_66.
A (mysterious) role plays the method "public boolean close(long timeout)" in the class B: if it doesn't exist, the error doesn't occur.


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Compile the attached two classes with javac on the command-line (eg. javac *.java).


ERROR MESSAGES/STACK TRACES THAT OCCUR :
An exception has occurred in the compiler (1.8.0_91). 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.AssertionError: isSubClass C
        at com.sun.tools.javac.code.Symbol.isSubClass(Symbol.java:447)
        at com.sun.tools.javac.code.Symbol.isMemberOf(Symbol.java:456)
        at com.sun.tools.javac.code.Symbol$MethodSymbol.overrides(Symbol.java:1479)
        at com.sun.tools.javac.code.Types$ImplementationCache.implementationInternal(Types.java:2693)
        at com.sun.tools.javac.code.Types$ImplementationCache.get(Types.java:2675)
        at com.sun.tools.javac.code.Types.implementation(Types.java:2704)
        at com.sun.tools.javac.code.Symbol$MethodSymbol.implementation(Symbol.java:1539)
        at com.sun.tools.javac.code.Symbol$MethodSymbol.implementation(Symbol.java:1528)
        at com.sun.tools.javac.comp.Resolve.notOverriddenIn(Resolve.java:419)
        at com.sun.tools.javac.comp.Resolve.isAccessible(Resolve.java:405)
        at com.sun.tools.javac.comp.Resolve.isAccessible(Resolve.java:365)
        at com.sun.tools.javac.comp.Resolve.selectBest(Resolve.java:1457)
        at com.sun.tools.javac.comp.Resolve.findMethodInScope(Resolve.java:1627)
        at com.sun.tools.javac.comp.Resolve.findMethod(Resolve.java:1719)
        at com.sun.tools.javac.comp.Resolve.findMethod(Resolve.java:1671)
        at com.sun.tools.javac.comp.Resolve$9.doLookup(Resolve.java:2424)
        at com.sun.tools.javac.comp.Resolve$BasicLookupHelper.lookup(Resolve.java:3083)
        at com.sun.tools.javac.comp.Resolve.lookupMethod(Resolve.java:3334)
        at com.sun.tools.javac.comp.Resolve.resolveQualifiedMethod(Resolve.java:2421)
        at com.sun.tools.javac.comp.Resolve.resolveQualifiedMethod(Resolve.java:2415)
        at com.sun.tools.javac.comp.Resolve.resolveQualifiedMethod(Resolve.java:2410)
        at com.sun.tools.javac.comp.Attr.checkAutoCloseable(Attr.java:1389)
        at com.sun.tools.javac.comp.Attr.visitTry(Attr.java:1335)
        at com.sun.tools.javac.tree.JCTree$JCTry.accept(JCTree.java:1173)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:566)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:635)
        at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:651)
        at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1114)
        at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:909)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:566)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:635)
        at com.sun.tools.javac.comp.Attr.visitMethodDef(Attr.java:1003)
        at com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:778)
        at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:566)
        at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:635)
        at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:4340)
        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4248)
        at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:4177)
        at com.sun.tools.javac.comp.Attr.attrib(Attr.java:4152)
        at com.sun.tools.javac.main.JavaCompiler.attribute(JavaCompiler.java:1248)
        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)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
abstract class B implements AutoCloseable {
    @Override
    public void close() {
    }

    public boolean close(long timeout) {
        return true;
    }
}

public abstract class A<C extends B> {
    abstract C newCloseable();
    
    void m() throws Exception{
        try(C p= newCloseable()){
        }
    }
    
}

---------- END SOURCE ----------