Build error on substrate-node-template with missing target

Question

I am getting this error:

Rust WASM toolchain not installed, please install it!

  Further error information:
  ------------------------------------------------------------
     Compiling wasm-test v1.0.0 (/var/folders/cw/dc7mkcsd6yx76lscv6w1hpcw0000gn/T/.tmp3NWr2N)
  error[E0463]: can't find crate for `std`
    |
    = note: the `wasm32-unknown-unknown` target may not be installed
    = help: consider downloading the target with `rustup target add wasm32-unknown-unknown`

  error: requires `sized` lang_item

  libunwind: malformed __unwind_info at 0x18AC83CA8 bad second level page
  error: cannot find macro `println` in this scope
   --> src/main.rs:3:5
    |
  3 |                 println!("{}", env!("RUSTC_VERSION"));
    |                 ^^^^^^^

  For more information about this error, try `rustc --explain E0463`.
  libunwind: malformed __unwind_info at 0x18AC83CA8 bad second level page
  error: could not compile `wasm-test` (lib) due to 2 previous errors
  warning: build failed, waiting for other jobs to finish...
  error: could not compile `wasm-test` (bin "wasm-test") due to 3 previous errors
  ------------------------------------------------------------

warning: build failed, waiting for other jobs to finish...

I have already installed the target. But still getting the same error.🤔

Any suggestion for fix?

Answer 1

Some related doc: https://paritytech.github.io/polkadot-sdk/master/substrate_wasm_builder/index.html#prerequisites

Copy pasted for history:

Wasm builder requires the following prerequisites for building the Wasm binary:

• rust nightly + wasm32-unknown-unknown toolchain

or

• rust stable and version at least 1.68.0 + wasm32-unknown-unknown toolchain

If a specific rust is installed with rustup, it is important that the wasm target is installed as well. For example if installing the rust from 20.02.2020 using rustup install nightly-2020-02-20, the wasm target needs to be installed as well rustup target add wasm32-unknown-unknown --toolchain nightly-2020-02-20

Answer 2

I ensured wasm32-unknown-unknown target is installed in my system. But, still it had issues. Then, I just reinstalled rustup. I think something might have messed-up due to switching channels.