A DESCRIPTION OF THE PROBLEM :
java: An exception has occurred in the compiler (16.0.1). 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, the following diagnostic, and the parameters passed to the Java compiler in your report. Thank you.
java: java.lang.AssertionError: Incorrect number of arguments; expected 2, found 0
java: at jdk.compiler/com.sun.tools.javac.util.Assert.error(Assert.java:162)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitApply(TransTypes.java:666)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1745)
java: at jdk.compiler/com.sun.tools.javac.tree.TreeTranslator.translate(TreeTranslator.java:58)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.translate(TransTypes.java:455)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitLambda(TransTypes.java:541)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCLambda.accept(JCTree.java:1922)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.translateArgs(TransTypes.java:213)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitApply(TransTypes.java:669)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitVarDef(TransTypes.java:500)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:983)
java: at jdk.compiler/com.sun.tools.javac.tree.TreeTranslator.translate(TreeTranslator.java:70)
java: at jdk.compiler/com.sun.tools.javac.tree.TreeTranslator.visitBlock(TreeTranslator.java:167)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1047)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitReturn(TransTypes.java:622)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCReturn.accept(JCTree.java:1657)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitMethodDef(TransTypes.java:490)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:893)
java: at jdk.compiler/com.sun.tools.javac.tree.TreeTranslator.visitClassDef(TreeTranslator.java:139)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.translateClass(TransTypes.java:948)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.visitClassDef(TransTypes.java:476)
java: at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:790)
java: at jdk.compiler/com.sun.tools.javac.comp.TransTypes.translateTopLevelClass(TransTypes.java:972)
java: at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.desugar(JavaCompiler.java:1556)
java: at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.desugar(JavaCompiler.java:1435)
java: at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:973)
java: at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
java: at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.invocationHelper(JavacTaskImpl.java:152)
java: at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
java: at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:94)
java: at org.jetbrains.jps.javac.JavacMain.compile(JavacMain.java:238)
java: at org.jetbrains.jps.incremental.java.JavaBuilder.lambda$compileJava$2(JavaBuilder.java:513)
java: at org.jetbrains.jps.incremental.java.JavaBuilder.invokeJavac(JavaBuilder.java:559)
java: at org.jetbrains.jps.incremental.java.JavaBuilder.compileJava(JavaBuilder.java:511)
java: at org.jetbrains.jps.incremental.java.JavaBuilder.compile(JavaBuilder.java:354)
java: at org.jetbrains.jps.incremental.java.JavaBuilder.doBuild(JavaBuilder.java:279)
java: at org.jetbrains.jps.incremental.java.JavaBuilder.build(JavaBuilder.java:233)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.runModuleLevelBuilders(IncProjectBuilder.java:1485)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.runBuildersForChunk(IncProjectBuilder.java:1123)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.buildTargetsChunk(IncProjectBuilder.java:1268)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.buildChunkIfAffected(IncProjectBuilder.java:1088)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.buildChunks(IncProjectBuilder.java:854)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.runBuild(IncProjectBuilder.java:441)
java: at org.jetbrains.jps.incremental.IncProjectBuilder.build(IncProjectBuilder.java:190)
java: at org.jetbrains.jps.cmdline.BuildRunner.runBuild(BuildRunner.java:132)
java: at org.jetbrains.jps.cmdline.BuildSession.runBuild(BuildSession.java:318)
java: at org.jetbrains.jps.cmdline.BuildSession.run(BuildSession.java:146)
java: at org.jetbrains.jps.cmdline.BuildMain$MyMessageHandler.lambda$channelRead0$0(BuildMain.java:218)
java: at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1130)
java: at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:630)
java: at java.base/java.lang.Thread.run(Thread.java:831)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
In the following expression remove the type of TypeLiteral. This code compiles:

OakKnownTypes.OakRecord<K> keyRecord =
        Optional.ofNullable(OakKnownTypes.lookupRecord(key))
        .orElseGet(() -> helper.getOrDefault(new TypeLiteral<OakKnownTypes.OakRecord<K>>() {}, () -> inferOakRecord(key)));


This one fails:
OakKnownTypes.OakRecord<K> keyRecord =
                    Optional.ofNullable(OakKnownTypes.lookupRecord(key))
                    .orElseGet(() -> helper.getOrDefault(new TypeLiteral<>() {}, () -> inferOakRecord(key)));