Add nightly toolchain to commands

src/build.rs

@@ -7,10 +7,13 @@ use PBAR;
 pub fn rustup_add_wasm_target(step: &Step) -> Result<(), Error> {
     let msg = format!("{}Adding WASM target...", emoji::TARGET);
     let pb = PBAR.step(step, &msg);
+    ensure_nightly()?;
     let output = Command::new("rustup")
         .arg("target")
         .arg("add")
         .arg("wasm32-unknown-unknown")
+        .arg("--toolchain")
+        .arg("nightly")
         .output()?;
     pb.finish();
     if !output.status.success() {
@@ -21,12 +24,28 @@ pub fn rustup_add_wasm_target(step: &Step) -> Result<(), Error> {
     }
 }
 
+fn ensure_nightly() -> Result<(), Error> {
+    let nightly_check = Command::new("rustc").arg("+nightly").arg("-V").output()?;
+    if !nightly_check.status.success() {
+        let res = Command::new("rustup")
+            .arg("toolchain")
+            .arg("install")
+            .arg("nightly")
+            .output()?;
+        if !res.status.success() {
+            let s = String::from_utf8_lossy(&res.stderr);
+            return Error::cli("Adding the nightly toolchain failed", s);
+        }
+    }
+    Ok(())
+}
+
 pub fn cargo_build_wasm(path: &str, debug: bool, step: &Step) -> Result<(), Error> {
     let msg = format!("{}Compiling to WASM...", emoji::CYCLONE);
     let pb = PBAR.step(step, &msg);
     let output = {
         let mut cmd = Command::new("cargo");
-        cmd.current_dir(path).arg("build");
+        cmd.current_dir(path).arg("+nightly").arg("build");
         if !debug {
             cmd.arg("--release");
         }

src/emoji.rs

@@ -12,3 +12,4 @@ pub static WARN: Emoji = Emoji("⚠️  ", ":-)");
 pub static DANCERS: Emoji = Emoji("👯  ", "");
 pub static ERROR: Emoji = Emoji("⛔  ", "");
 pub static INFO: Emoji = Emoji("ℹ️  ", "");
+pub static WRENCH: Emoji = Emoji("🔧  ", "");