node method for Synth goes out of bounds of phase in next.rs

[SnoCold]

Describe the bug The Handling of Node::Sine in the method node of Synth implementation goes out of bounds for the piano example the osc count keeps on increasing with no check, leading to out-of-bounds panic

To Reproduce Steps to reproduce the behavior:

run> cargo run --example piano

Expected behavior piano.wav should get generated without errors

Tried FIx I added an if block to return if the osc ever gets equal or higher to phase length

in next.rs inside fn node

 Node::Sine { hz } => {
                if *osc >= self.phase.len() { //Added this block
                    return
                }
                let this = *osc;
                *osc += 1;
                self.node(hz, delta, osc); 
                for i in self.stack.last_mut().unwrap() {
                    let hertz = *i;
                    *i = libm::cosf(self.phase[this] * core::f32::consts::TAU);
                    self.phase[this] = (self.phase[this] + delta * hertz) % 1.0;
                }
            }

Desktop (please complete the following information):

• OS: Debian on Wsl2
• Version: 6.6.87.2-microsoft-standard-WSL2

Additional context Backtrace:

thread 'main' panicked at src/next.rs:520:47:
index out of bounds: the len is 30 but the index is 30
stack backtrace:
   0: __rustc::rust_begin_unwind
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/std/src/panicking.rs:697:5
   1: core::panicking::panic_fmt
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/panicking.rs:75:14
   2: core::panicking::panic_bounds_check
             at /rustc/1159e78c4747b02ef996e55082b704c09b970588/library/core/src/panicking.rs:280:5
   3: <usize as core::slice::index::SliceIndex<[T]>>::index
             at /home/nishshuk/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/slice/index.rs:274:10
   4: core::slice::index::<impl core::ops::index::Index<I> for [T]>::index
             at /home/nishshuk/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/slice/index.rs:18:15
   5: <alloc::vec::Vec<T,A> as core::ops::index::Index<I>>::index
             at /home/nishshuk/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/alloc/src/vec/mod.rs:3571:9
   6: twang::next::Synth::node
             at ./src/next.rs:520:47
   7: twang::next::Synth::node
             at ./src/next.rs:615:22
   8: twang::next::Synth::node
             at ./src/next.rs:505:26
   9: twang::next::Synth::node
             at ./src/next.rs:505:26
  10: twang::next::Synth::node
             at ./src/next.rs:615:22
  11: twang::next::Synth::synthesize
             at ./src/next.rs:490:14
  12: <twang::next::SynthIter as core::iter::traits::iterator::Iterator>::next
             at ./src/next.rs:635:20
  13: <core::iter::adapters::map::Map<I,F> as core::iter::traits::iterator::Iterator>::next
             at /home/nishshuk/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/iter/adapters/map.rs:107:19
  14: <&mut fon::audio::AudioSink<Chan,_> as fon::sink::Sink<Chan,_>>::sink_with
             at /home/nishshuk/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/fon-0.6.0/src/audio.rs:192:48
  15: <fon::audio::AudioSink<Chan,_> as fon::sink::Sink<Chan,_>>::sink_with
             at /home/nishshuk/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/fon-0.6.0/src/audio.rs:172:9
  16: twang::next::Synth::stream
             at ./src/next.rs:477:14
  17: piano::main
             at ./examples/piano.rs:68:11
  18: core::ops::function::FnOnce::call_once
             at /home/nishshuk/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/ops/function.rs:253:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.