While attempting to compile gcj, it throws, among other things, a segfault
that I have traced back to line 536 of gcc/java/typeck.cc (on my
msterstable branch https://github.com/Zopolis4/gcj/tree/msterstable).

The segfault is due to the DECL_NAME call, which then fails
the contains_struct_check and causes a segfault.

According to 5a5e7deb5f93f04e027fd5baa1876370d6d6697f and
78fcec3fee63f10cfde06c252fc391e768c64b12, the correct fix would be to wrap
the call in DECL_NAME, no?

Yet that just causes the contains_struct_check to fail on the if DECL_NAME
(TYPE_NAME (type)) call.

What is the proper way to solve this?

libtool: compile:  /home/zopolis4/gcjbuild/./gcc/gcj
-B/home/zopolis4/gcjbuild/x86_64-pc-linux-gnu/libjava/
-B/home/zopolis4/gcjbuild/./gcc/ -B/usr/local/x86_64-pc-linux-gnu/bin/
-B/usr/local/x86_64-pc-linux-gnu/lib/ -isystem
/usr/local/x86_64-pc-linux-gnu/include -isystem
/usr/local/x86_64-pc-linux-gnu/sys-include -fomit-frame-pointer -Usun
-fclasspath=
-fbootclasspath=/home/zopolis4/gcjbuild/../gcj/libjava/classpath/lib
--encoding=UTF-8 -Wno-deprecated -fbootstrap-classes -g -O2 -c
-fsource-filename=/home/zopolis4/gcjbuild/x86_64-pc-linux-gnu/libjava/classpath/lib/classes
-MT gnu/awt/j2d.lo -MD -MP -MF gnu/awt/j2d.deps @gnu/awt/j2d.list  -fPIC -o
gnu/awt/.libs/j2d.o
/home/zopolis4/gcj/libjava/gnu/awt/j2d/AbstractGraphicsState.java: In class
'gnu.awt.j2d.AbstractGraphicsState':
/home/zopolis4/gcj/libjava/gnu/awt/j2d/AbstractGraphicsState.java: In
method 'gnu.awt.j2d.AbstractGraphicsState.clone()':
In file included from <built-in>:351:
/home/zopolis4/gcj/libjava/gnu/awt/j2d/AbstractGraphicsState.java:133:
internal compiler error: Segmentation fault
  133 |         return super.clone ();
      |
0xda20cf crash_signal
        /home/zopolis4/gcjbuild/../gcj/gcc/toplev.cc:322
0x86be61 contains_struct_check(tree_node*, tree_node_structure_enum, char
const*, int, char const*)
        /home/zopolis4/gcjbuild/../gcj/gcc/tree.h:3621
0x86be61 build_java_signature(tree_node*)
        /home/zopolis4/gcjbuild/../gcj/gcc/java/typeck.cc:536
0x86b7c4 shallow_find_method
        /home/zopolis4/gcjbuild/../gcj/gcc/java/typeck.cc:650
0x86b9f6 lookup_do
        /home/zopolis4/gcjbuild/../gcj/gcc/java/typeck.cc:756
0x864d8a expand_invoke
        /home/zopolis4/gcjbuild/../gcj/gcc/java/expr.cc:2462
0x866193 process_jvm_instruction(int, unsigned char const*, long)
        /home/zopolis4/gcjbuild/../gcj/gcc/java/javaop.def:292
0x86884f expand_byte_code(JCF*, tree_node*)
        /home/zopolis4/gcjbuild/../gcj/gcc/java/expr.cc:3244
0x87f494 parse_class_file
        /home/zopolis4/gcjbuild/../gcj/gcc/java/jcf-parse.cc:1658
0x87fd2d java_parse_file()
        /home/zopolis4/gcjbuild/../gcj/gcc/java/jcf-parse.cc:1976
Please submit a full bug report, with preprocessed source (by using
-freport-bug).
Please include the complete backtrace with any bug report.
See <https://gcc.gnu.org/bugs/> for instructions.
make[3]: *** [Makefile:10625: gnu/awt/j2d.lo] Error 1