[raiyan-ironsoftware]

Enabling wasm_js while selecting an explicit non-JavaScript backend fails to compile on wasm32-unknown-unknown:

RUSTFLAGS='--cfg getrandom_backend="unsupported"' \
  cargo check --target wasm32-unknown-unknown --features wasm_js

error[E0599]: no associated function or constant named `WEB_CRYPTO`
found for struct `error::Error` in the current scope

The same error occurs with the custom backend. A transitive dependency can enable wasm_js, so this configuration is useful for non-JavaScript Wasm applications that explicitly override the default backend.

internal_desc checks the feature and target, but Error::WEB_CRYPTO is defined only when the wasm_js backend is selected. Exclude the supported non-JavaScript overrides (unsupported, custom, and extern_impl) from that match arm. This changes no entropy source or runtime error behavior.

The existing override build job now covers unsupported and custom, both with and without wasm_js. These feature-enabled builds fail on the base revision and pass with this change.

Validated locally:

• Reproduced E0599 on the unmodified base with unsupported and custom.
• Wasm builds for unsupported and custom, with and without wasm_js, with warnings denied.
• Wasm checks for unsupported, custom, and extern_impl, with wasm_js and wasm_js,std.
• Default JavaScript-backend Wasm check with wasm_js.
• Native cargo test --locked --all-features: 11 integration tests and 9 doctests passed; 1 existing doctest ignored.
• cargo fmt --all -- --check and git diff --check.