rusti always leaks memory and crashes

[cantsin]

rusti on latest incoming (c081ffb) and master (f547a67) seems to always crash. Even simple expressions fail:

WARNING: The Rust REPL is experimental and may be
unstable. If you encounter problems, please use the
compiler instead.
rusti> 5
rust: ~"blocked = 0 this = 15e82c0"
rust: ~"blocked = 15e82c0 this = 15e82c0 old_task = 0"
rust: ~"no data available on &mut {header: {state: Blocked, blocked_task: (0x15e82c0 as *()), buffer: (0x7fb3f4204090 as *())}, payload: None}, going to sleep."
rust: ~"\"building driver input\""
rust: ~"inputting // Copyright 2012 The Rust Project Developers. See the COPYRIGHT\n// file at the top-level directory of this distribution and at\n// http://rust-lang.org/COPYRIGHT.\n//\n// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or\n// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license\n// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your\n// option. This file may not be copied, modified, or distributed\n// except according to those terms.\n\n#[allow(ctypes)];\n#[allow(heap_memory)];\n#[allow(implicit_copies)];\n#[allow(managed_heap_memory)];\n#[allow(non_camel_case_types)];\n#[allow(non_implicitly_copyable_typarams)];\n#[allow(owned_heap_memory)];\n#[allow(path_statement)];\n#[allow(unrecognized_lint)];\n#[allow(unused_imports)];\n#[allow(vecs_implicitly_copyable)];\n#[allow(while_true)];\n\nextern mod std;\n\nfn print<T>(result: T) {\n    io::println(fmt!(\"%?\", result));\n}\n\nfn main() {\n\n\nprint({\n5\n})\n}"
rust: ~"\"building a driver session\""
rust: ~"\"building driver configuration\""
rust: ~"\"calling compile_upto\""
5
rust: ~"\"recording input into repl history\""
rust: ~"woke up, p.state = Full"
rusti> leaked memory in rust main loop (1 objects)
memory_region::~memory_region(): Assertion `false' failed.```

[cantsin]

I tried to get at the precise problem, but I am not familiar with rust internals. My guess: it looks like the section that does "LLVM passes" in compile_rest (librustc/driver/driver.rs) is doing something wonky.