ADDITIONAL SYSTEM INFORMATION :
Linux Mint 18.3, 64-bit;
Java 1.8.0_191, 10.0.2, 11, 12-ea (2019-03-19).

A DESCRIPTION OF THE PROBLEM :
Trying to compile the code attached throws an error from the Java compiler.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Create a java file with the attached code
2. Run "javac code.java"

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The corresponding class files get generated
ACTUAL -
The following error is thrown by javac:
java.lang.NullPointerException
at jdk.compiler/com.sun.tools.javac.code.Types.getBounds(Types.java:2677)
at jdk.compiler/com.sun.tools.javac.comp.Check.checkNonCyclic1(Check.java:2292)
at jdk.compiler/com.sun.tools.javac.comp.Check.checkNonCyclic1(Check.java:2293)
at jdk.compiler/com.sun.tools.javac.comp.Check.checkNonCyclic(Check.java:2278)
at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTypeVariables(Attr.java:815)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$HeaderPhase.runPhase(TypeEnter.java:835)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.doCompleteEnvs(TypeEnter.java:282)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.completeEnvs(TypeEnter.java:251)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.completeEnvs(TypeEnter.java:266)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.completeEnvs(TypeEnter.java:266)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter.complete(TypeEnter.java:198)
at jdk.compiler/com.sun.tools.javac.code.Symbol.complete(Symbol.java:642)
at jdk.compiler/com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1326)
at jdk.compiler/com.sun.tools.javac.code.Symbol$ClassSymbol.flags(Symbol.java:1259)
at jdk.compiler/com.sun.tools.javac.comp.Resolve.isAccessible(Resolve.java:403)
at jdk.compiler/com.sun.tools.javac.comp.Resolve.isAccessible(Resolve.java:387)
at jdk.compiler/com.sun.tools.javac.comp.Resolve.findImmediateMemberType(Resolve.java:2169)
at jdk.compiler/com.sun.tools.javac.comp.Resolve.findMemberType(Resolve.java:2224)
at jdk.compiler/com.sun.tools.javac.comp.Resolve.findIdentInTypeInternal(Resolve.java:2420)
at jdk.compiler/com.sun.tools.javac.comp.Resolve.findIdentInType(Resolve.java:2406)
at jdk.compiler/com.sun.tools.javac.comp.Attr.selectSym(Attr.java:3932)
at jdk.compiler/com.sun.tools.javac.comp.Attr.visitSelect(Attr.java:3802)
at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCFieldAccess.accept(JCTree.java:2189)
at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTree(Attr.java:664)
at jdk.compiler/com.sun.tools.javac.comp.Attr.attribType(Attr.java:728)
at jdk.compiler/com.sun.tools.javac.comp.Attr.attribType(Attr.java:721)
at jdk.compiler/com.sun.tools.javac.comp.Attr.attribTypeVariables(Attr.java:803)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$HeaderPhase.runPhase(TypeEnter.java:835)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.doCompleteEnvs(TypeEnter.java:282)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.completeEnvs(TypeEnter.java:251)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.completeEnvs(TypeEnter.java:266)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter$Phase.completeEnvs(TypeEnter.java:266)
at jdk.compiler/com.sun.tools.javac.comp.TypeEnter.complete(TypeEnter.java:198)
at jdk.compiler/com.sun.tools.javac.code.Symbol.complete(Symbol.java:642)
at jdk.compiler/com.sun.tools.javac.code.Symbol$ClassSymbol.complete(Symbol.java:1326)
at jdk.compiler/com.sun.tools.javac.comp.Enter.complete(Enter.java:584)
at jdk.compiler/com.sun.tools.javac.comp.Enter.main(Enter.java:561)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.enterTrees(JavaCompiler.java:1066)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:937)
at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:311)
at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:170)
at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:57)
at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:43)


---------- BEGIN SOURCE ----------
class O<A extends O.I, B> {
  class I<Bc extends B> { }
}
---------- END SOURCE ----------

FREQUENCY : always