game_of_life panic with wasm32-unknown-unknown target

[huangjj27]

Description

I'm submitting a question

As I didn't install emscripten tools, I Add a Web.toml to the example(cloned with the yew git repo) to change the default target to rustup's wasm32-unknown-unknown, then build.

Expected Results

the game should be shown and the buttons shoud work

Actual Results

Encounter a panic

Error loading Rust wasm module 'game_of_life': 
RuntimeError: unreachable executed
Stack trace:
__rust_start_panic@http://localhost:8000/js/app.js:209947:1
rust_panic@http://localhost:8000/js/app.js:183360:1
std::panicking::rust_panic_with_hook::hf4ad10abe765e9ff@http://localhost:8000/js/app.js:182671:1
std::panicking::begin_panic::ha5da3b9a0ddd8a9c@http://localhost:8000/js/app.js:120745:1
rand::jitter::platform::get_nstime::h4cc03776153f98ea@http://localhost:8000/js/app.js:127147:1
rand::jitter::JitterRng::new::hfac017917be80b30@http://localhost:8000/js/app.js:120988:1
rand::StdRng::new::h1afb735546c910f1@http://localhost:8000/js/app.js:126336:1
rand::thread_rng::had3d49e398e9a8e1@http://localhost:8000/js/app.js:126671:1
game_of_life::GameOfLife::random_mutate::h8281d6d903d3b176@http://localhost:8000/js/app.js:118907:1
<game_of_life::GameOfLife as yew::html::Component<CTX>>::update::hdc61c8ae6698d50f@http://localhost:8000/js/app.js:47402:1
<yew::html::ScopeRunnable<CTX, COMP> as yew::scheduler::Runnable<CTX>>::run::h3f76b29a1fa234bf@http://localhost:8000/js/app.js:110844:1
<yew::scheduler::Scheduler<CTX>>::put_and_try_run::hb8d7905369887aaa@http://localhost:8000/js/app.js:32972:1
game_of_life::main::h824f031b0ddc5e23@http://localhost:8000/js/app.js:47720:1
std::rt::lang_start::{{closure}}::h44a175b82135c044@http://localhost:8000/js/app.js:48527:1
std::sys_common::backtrace::__rust_begin_short_backtrace::hd5da1a247f4ba467@http://localhost:8000/js/app.js:186903:1
std::panicking::try::do_call::h897e358b832c26f7@http://localhost:8000/js/app.js:182015:1
__rust_maybe_catch_panic@http://localhost:8000/js/app.js:209939:1
std::rt::lang_start_internal::h5bf01d0092e63ea4@http://localhost:8000/js/app.js:191982:1
main@http://localhost:8000/js/app.js:48095:1
__instantiate@http://localhost:8000/js/app.js:608:9
__initialize/<@http://localhost:8000/js/app.js:614:17

Context (Environment)

• Rust: 1.27.0-nightly (e82261dfb 2018-05-03)

• yew: master c4320fd

• target: wasm32-unknown-unknown

• cargo-web: v0.6.10

• browser if relevant: Firefox Quantum 58

[dhardy]

Looks like you tried executing unreachable!(). Try building Rand with the stdweb feature.

[huangjj27]

@dhardy thanks! it fixed the issue