diff --git a/Makefile b/Makefile
index 7b1a466ca5e..7d8d6996885 100644
--- a/Makefile
+++ b/Makefile
@@ -282,3 +282,7 @@ force-update-assets: ## As update-assets, but will run git to update the baselin
 
 check-size: ## Run cargo-diet on all crates to see that they are still in bound
 	./etc/check-package-size.sh
+
+rustfmt: ## run nightly rustfmt for its extra features, but check that it won't upset stable rustfmt
+	cargo +nightly fmt --all -- --config-path rustfmt-nightly.toml
+	cargo +stable fmt --all -- --check
diff --git a/rustfmt-nightly.toml b/rustfmt-nightly.toml
new file mode 100644
index 00000000000..1a25d9c9295
--- /dev/null
+++ b/rustfmt-nightly.toml
@@ -0,0 +1,3 @@
+group_imports = "StdExternalCrate"
+imports_granularity = "Crate"
+max_width = 120