This exception is issued:

java.lang.NullPointerException: Cannot invoke "org.openjdk.jextract.Declaration$Constant.name()" because "<parameter2>" is null
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.TreeMaker.enumConstantString(TreeMaker.java:532)
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.TreeMaker.lambda$createEnum$7(TreeMaker.java:375)
        at java.base/java.util.ArrayList.forEach(ArrayList.java:1597)
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.TreeMaker.createEnum(TreeMaker.java:373)
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.TreeMaker.createTreeInternal(TreeMaker.java:133)
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.TreeMaker.createTree(TreeMaker.java:119)
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.Parser.lambda$parse$2(Parser.java:86)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.Cursor$CursorChildren.lambda$forEach$1(Cursor.java:261)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.Cursor$CursorChildren$Context.visit(Cursor.java:234)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.Cursor$CursorChildren.lambda$static$0(Cursor.java:252)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.libclang.Index_h.clang_visitChildren(Index_h.java:8275)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.Cursor$CursorChildren.forEachShortCircuit(Cursor.java:271)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.Cursor$CursorChildren.forEach(Cursor.java:260)
        at org.openjdk.jextract@22/org.openjdk.jextract.clang.Cursor.forEach(Cursor.java:201)
        at org.openjdk.jextract@22/org.openjdk.jextract.impl.Parser.parse(Parser.java:64)
        at org.openjdk.jextract@22/org.openjdk.jextract.JextractTool.parse(JextractTool.java:119)
        at org.openjdk.jextract@22/org.openjdk.jextract.JextractTool.run(JextractTool.java:516)
        at org.openjdk.jextract@22/org.openjdk.jextract.JextractTool.main(JextractTool.java:218)


When extracting some system header files on MacOS. It seems that the problematic declaration is this:

enum __CFByteOrder {
    CFByteOrderUnknown,
    CFByteOrderLittleEndian,
    CFByteOrderBigEndian
};

However, this declaration is pretty basic, and does not cause issues on other platforms. Perhaps this might also indicate a bug in libclang reporting a bogus nested declaration.