ci: Check that all features that are used exist

With the new `check-cfg=features` option

.github/workflows/nightly.yml

@@ -23,6 +23,9 @@ jobs:
           - name: Full Features
             cmd: nightly-full
 
+          - name: All Features
+            cmd: nightly-all
+
           - name: Clippy Default Features
             cmd: clippy-default
             components: clippy

xtask/src/ci.rs

@@ -52,6 +52,8 @@ pub enum CiCmd {
     Fmt,
     /// Check ruma crate with `full` features (nightly)
     NightlyFull,
+    /// Check all crates with all features (nightly)
+    NightlyAll,
     /// Lint default features with clippy (nightly)
     ClippyDefault,
     /// Lint ruma-common with clippy on a wasm target (nightly)
@@ -103,6 +105,7 @@ impl CiTask {
             Some(CiCmd::Nightly) => self.nightly()?,
             Some(CiCmd::Fmt) => self.fmt()?,
             Some(CiCmd::NightlyFull) => self.nightly_full()?,
+            Some(CiCmd::NightlyAll) => self.nightly_all()?,
             Some(CiCmd::ClippyDefault) => self.clippy_default()?,
             Some(CiCmd::ClippyWasm) => self.clippy_wasm()?,
             Some(CiCmd::ClippyAll) => self.clippy_all()?,
@@ -220,6 +223,16 @@ impl CiTask {
         cmd!("rustup run {NIGHTLY} cargo check -p ruma --features full").run().map_err(Into::into)
     }
 
+    /// Check all crates with all features with the nightly version.
+    ///
+    /// Also checks that all features that are used in the code exist.
+    fn nightly_all(&self) -> Result<()> {
+        cmd!("rustup run {NIGHTLY} cargo check --workspace --all-features -Z unstable-options -Z check-cfg=features")
+            .env("RUSTFLAGS", "-D warnings")
+            .run()
+            .map_err(Into::into)
+    }
+
     /// Check ruma-common with `ruma_identifiers_storage="Box"`
     fn msrv_owned_id_box(&self) -> Result<()> {
         cmd!("rustup run {MSRV} cargo check -p ruma-common")