internal compiler error in check_match.rs #4974

rustc --version
rustc 0.6 (9143688 2013-02-14 14:44:12 -0800)
host: x86_64-unknown-linux-gnu

Found ICE when compiling this snippet:

fn main() {
match 0 {
y if y < 0 => ()
}
}

Here is the backtrace:
rust: task failed at 'Assertion (!pats.is_empty()) failed', .../src/librustc/middle/check_match.rs:135
/usr/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7f7c0fd2aeeb]
/usr/bin/../lib/librustrt.so(+0x2ac29)[0x7f7c0fd3bc29]
/usr/bin/../lib/librustrt.so(upcall_fail+0x180)[0x7f7c0fd2ccf0]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xf858b)[0x7f7c1187358b]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x402de)[0x7f7c117bb2de]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6middle11check_match16check_exhaustive16_c41dd2a15ed85183_06E+0xa7f)[0x7f7c1058032f]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6middle11check_match10check_expr17_91da63eec117a1fb3_06E+0x865)[0x7f7c1057c365]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x3febae)[0x7f7c1036bbae]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6middle11check_match8check_fn17_307b4ac256cbd1fb3_06E+0x153)[0x7f7c1057cd53]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x60fbf7)[0x7f7c1057cbf7]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x3fd1e0)[0x7f7c1036a1e0]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x3fc9c4)[0x7f7c103699c4]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6middle11check_match11check_crate17_4eb7bea3f5c7f29d3_06E+0x439)[0x7f7c1057b3f9]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x8c17f6)[0x7f7c1082e7f6]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x908254)[0x7f7c10875254]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver12compile_upto17_8d63b5f164a5111b3_06E+0x1d13)[0x7f7c1082a8d3]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x908254)[0x7f7c10875254]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN6driver6driver13compile_input15_ec93634a1749fa3_06E+0xb9)[0x7f7c1082ee19]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN12run_compiler16_effc976f5954f613_06E+0x2218)[0x7f7c10860f98]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x905241)[0x7f7c10872241]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x90385e)[0x7f7c1087085e]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x908254)[0x7f7c10875254]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xc3d74)[0x7f7c1183ed74]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x129dc0)[0x7f7c118a4dc0]
/usr/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x7f7c0fd2b754]
error: internal compiler error: unexpected failure
note: the compiler hit an unexpected failure path. this is a bug
note: try running with RUST_LOG=rustc=1,::rt::backtrace to get further details and report the results to github.com/mozilla/rust/issues
rust: task failed at 'explicit failure', .../src/librustc/rustc.rc:371
/usr/bin/../lib/librustrt.so(_ZN9rust_task13begin_failureEPKcS1_m+0x4b)[0x7f7c0fd2aeeb]
/usr/bin/../lib/librustrt.so(+0x2ac29)[0x7f7c0fd3bc29]
/usr/bin/../lib/librustrt.so(upcall_fail+0x180)[0x7f7c0fd2ccf0]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xf858b)[0x7f7c1187358b]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0xf8532)[0x7f7c11873532]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(_ZN3sys12begin_unwind17_7cd364c41f10422f3_06E+0x71)[0x7f7c117bb771]
/usr/bin/../lib/libcore-c3ca5d77d81b46c1-0.6.so(+0x129dc0)[0x7f7c118a4dc0]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN7monitor17_43bc971c43c819df3_06E+0x5fb5)[0x7f7c10867e25]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(+0x908254)[0x7f7c10875254]
/usr/bin/../lib/librustc-c84825241471686d-0.6.so(_ZN4main16_706f4ee7413ae583_06E+0x7e)[0x7f7c10874e6e]
/usr/bin/../lib/librustrt.so(_Z18task_start_wrapperP10spawn_args+0x24)[0x7f7c0fd2b754]
rust: domain main @0x19dc3b0 root task failed