Trying to use rr for debugging https://github.com/espadrine/tree-array

rr.sh

$ rr record cargo test
rr: Saving execution to trace directory `/home/tyl/.local/share/rr/cargo-4'.
    Finished dev [unoptimized + debuginfo] target(s) in 0.01s                      
     Running target/debug/deps/bench_insert-8cb017bd9e593f1f

running 5 tests
test tests::bench_insert_list ... ok
test tests::bench_insert_vec ... ok
test tests::test_insert_list ... ok
test tests::test_insert_tree_array ... FAILED
test tests::test_insert_vec ... ok

failures:

---- tests::test_insert_tree_array stdout ----
tree: [2 size=2] left=([1 size=1] left=(nil) right=(nil)) right=(nil)
tree: [1 size=1] left=(nil) right=([2 size=0] left=(nil) right=(nil))
thread 'tests::test_insert_tree_array' panicked at 'assertion failed: `(left == right)`
  left: `1`,
 right: `2`', src/lib.rs:81:9
note: Run with `RUST_BACKTRACE=1` for a backtrace.


failures:
    tests::test_insert_tree_array

test result: FAILED. 4 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out

error: test failed, to rerun pass '--lib'

$ rr replay
GNU gdb (Ubuntu 8.1-0ubuntu3) 8.1.0.20180409-git
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and "show warranty" for details.
This GDB was configured as "x86_64-linux-gnu".
Type "show configuration" for configuration details.
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For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from /home/tyl/.local/share/rr/cargo-4/mmap_hardlink_3_cargo...done.
Really redefine built-in command "restart"? (y or n) [answered Y; input not from terminal]
Remote debugging using 127.0.0.1:19780
Reading symbols from /lib64/ld-linux-x86-64.so.2...Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/ld-2.27.so...done.
done.
0x00007f5c5acb0090 in _start () from /lib64/ld-linux-x86-64.so.2
(rr) break tree_array.rs:277
No source file named tree_array.rs.
Make breakpoint pending on future shared library load? (y or [n]) 
(rr) c
Continuing.

Program stopped.
0x0000000070000002 in ?? ()
(rr) p node.to_str()
A syntax error in expression, near `.to_str()'.
(rr) p node
Attempt to use a type name as an expression
(rr) p node_size
No symbol "node_size" in current context.
(rr) l
1       <built-in>: No such file or directory.
(rr)