example.c segfault

gistfile1.txt

Reading symbols from /home/knapper/projects/libCello/demos/a.out...done.
(gdb) run
Starting program: /home/knapper/projects/libCello/demos/a.out 
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?
Type: 'Int'
Type: 'Real'
Type: 'String'
Price of a 'Pear' is 55
Price of "Apple" is 12
Price of "Banana" is 6
Price of "Pear" is 55

Program received signal SIGSEGV, Segmentation fault.
Type_Class_Name (self=0x775f6c6169726573, 
    class_name=class_name@entry=0x7ffff7b6d668 "AsStr", 
    func=func@entry=0x7ffff7b6e90d <__func__.4599> "as_str", 
    file=file@entry=0x7ffff7b6e448 "Prelude.c", line=line@entry=339)
    at Type.c:83
83	  if (t[0].class_object != NULL) {
(gdb) bt
#0  Type_Class_Name (self=0x775f6c6169726573, 
    class_name=class_name@entry=0x7ffff7b6d668 "AsStr", 
    func=func@entry=0x7ffff7b6e90d <__func__.4599> "as_str", 
    file=file@entry=0x7ffff7b6e448 "Prelude.c", line=line@entry=339)
    at Type.c:83
#1  0x00007ffff7b6a36c in as_str (self=0x7ffff7b6e9ab <__func__.4681>)
    at Prelude.c:339
#2  0x00007ffff7b6530b in print_to_va (out=out@entry=0x7fffffffd390, pos=10, 
    pos@entry=0, 
    fmt=0x7ffff7b6ef6b "s' at '%s:%i' :: Type '%s' does not implement class '%s'", 
    fmt@entry=0x7ffff7b6ef60 "Function '%s' at '%s:%i' :: Type '%s' does not implement class '%s'", va=va@entry=0x7fffffffd3a8) at Format.c:129
#3  0x00007ffff7b644d1 in __exc_throw (obj=<optimized out>, 
    fmt=fmt@entry=0x7ffff7b6ef60 "Function '%s' at '%s:%i' :: Type '%s' does not implement class '%s'", file=file@entry=0x7ffff7b6ee17 "Type.c", 
    func=func@entry=0x7ffff7b6eff0 <__func__.3969> "Type_Class_Name", 
    lineno=lineno@entry=117) at Exception.c:107
#4  0x00007ffff7b6d359 in Type_Class_Name (
    self=0x7ffff7d759a0 <__compound_literal.0>, 
    class_name=class_name@entry=0x7ffff7b6d682 "Serialize", 
    func=func@entry=0x7ffff7b6e9ab <__func__.4681> "serial_write", 
    file=file@entry=0x7ffff7b6e448 "Prelude.c", line=line@entry=411)
    at Type.c:114
---Type <return> to continue, or q <return> to quit---return
#5  0x00007ffff7b6aa7c in serial_write (self=0x625290, output=0x7fffffffd6a0)
    at Prelude.c:411
#6  0x0000000000406307 in __LambdaPlus_write_pair (args=0x7fffffffd560)
    at example.c:53
#7  0x00007ffff7b66509 in call_with_ptr (self=self@entry=0x7fffffffd6b0, 
    args=args@entry=0x7fffffffd590) at Function.c:10
#8  0x00007ffff7b66558 in map (self=0x609070, func=0x7fffffffd6b0)
    at Lambda.c:10
#9  0x00000000004066d2 in main (argc=1, argv=0x7fffffffd7f8) at example.c:60
(gdb)