!!DONT Upgrade Rust to `nightly-2020-02-19`!!

[aurexav]

error[E0603]: struct `Memory` is private
    --> /Users/xavier/.cargo/registry/src/github.com-1ecc6299db9ec823/js-sys-0.3.35/src/lib.rs:4873:60
     |
4873 |                 let mem = buf.unchecked_ref::<WebAssembly::Memory>();
     |                                                            ^^^^^^ this struct is private
     |
note: the struct `Memory` is defined here
    --> /Users/xavier/.cargo/registry/src/github.com-1ecc6299db9ec823/js-sys-0.3.35/src/lib.rs:3516:5
     |
3516 |     #[wasm_bindgen]
     |     ^^^^^^^^^^^^^^^
     = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0603]: struct `Memory` is private
    --> /Users/xavier/.cargo/registry/src/github.com-1ecc6299db9ec823/js-sys-0.3.35/src/lib.rs:4898:60
     |
4898 |                 let mem = buf.unchecked_ref::<WebAssembly::Memory>();
     |                                                            ^^^^^^ this struct is private
     |
note: the struct `Memory` is defined here
    --> /Users/xavier/.cargo/registry/src/github.com-1ecc6299db9ec823/js-sys-0.3.35/src/lib.rs:3516:5
     |
3516 |     #[wasm_bindgen]
     |     ^^^^^^^^^^^^^^^
     = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

error[E0603]: struct `Memory` is private
    --> /Users/xavier/.cargo/registry/src/github.com-1ecc6299db9ec823/js-sys-0.3.35/src/lib.rs:4908:60
     |
4908 |                 let mem = buf.unchecked_ref::<WebAssembly::Memory>();
     |                                                            ^^^^^^ this struct is private
     |
note: the struct `Memory` is defined here
    --> /Users/xavier/.cargo/registry/src/github.com-1ecc6299db9ec823/js-sys-0.3.35/src/lib.rs:3516:5
     |
3516 |     #[wasm_bindgen]
     |     ^^^^^^^^^^^^^^^
     = note: this error originates in an attribute macro (in Nightly builds, run with -Z macro-backtrace for more info)

   Compiling prost v0.5.0
error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0603`.
error: could not compile `js-sys`.

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

[aurexav]

Recommend to stay at this version

rustup default nightly-2020-02-07
rustup target add wasm32-unknown-unknown

[aurexav]

rustwasm/wasm-bindgen#2009

[yanganto]

build pass also on rustc 1.43.0-nightly (5e7af4669 2020-02-16)

[aurexav]

Safe to switch to nightly now.