diff --git a/crates/proc-macro-srv-cli/build.rs b/crates/proc-macro-srv-cli/build.rs
new file mode 100644
index 0000000000000..07f914fece0e2
--- /dev/null
+++ b/crates/proc-macro-srv-cli/build.rs
@@ -0,0 +1,5 @@
+//! This teaches cargo about our cfg(rust_analyzer)
+
+fn main() {
+    println!("cargo:rustc-check-cfg=cfg(rust_analyzer)");
+}
diff --git a/crates/proc-macro-srv/build.rs b/crates/proc-macro-srv/build.rs
index a8c732f31541d..874d1c6cd389b 100644
--- a/crates/proc-macro-srv/build.rs
+++ b/crates/proc-macro-srv/build.rs
@@ -4,6 +4,8 @@
 use std::{env, fs::File, io::Write, path::PathBuf, process::Command};
 
 fn main() {
+    println!("cargo:rustc-check-cfg=cfg(rust_analyzer)");
+
     let mut path = PathBuf::from(env::var_os("OUT_DIR").unwrap());
     path.push("rustc_version.rs");
     let mut f = File::create(&path).unwrap();
diff --git a/crates/proc-macro-srv/proc-macro-test/build.rs b/crates/proc-macro-srv/proc-macro-test/build.rs
index c76c201d69e87..6a0ae362d88e9 100644
--- a/crates/proc-macro-srv/proc-macro-test/build.rs
+++ b/crates/proc-macro-srv/proc-macro-test/build.rs
@@ -53,7 +53,7 @@ fn main() {
     println!("Creating {}", src_dir.display());
     std::fs::create_dir_all(src_dir).unwrap();
 
-    for item_els in [&["Cargo.toml"][..], &["src", "lib.rs"]] {
+    for item_els in [&["Cargo.toml"][..], &["build.rs"][..], &["src", "lib.rs"]] {
         let mut src = imp_dir.clone();
         let mut dst = staging_dir.clone();
         for el in item_els {
diff --git a/crates/proc-macro-srv/proc-macro-test/imp/build.rs b/crates/proc-macro-srv/proc-macro-test/imp/build.rs
new file mode 100644
index 0000000000000..07f914fece0e2
--- /dev/null
+++ b/crates/proc-macro-srv/proc-macro-test/imp/build.rs
@@ -0,0 +1,5 @@
+//! This teaches cargo about our cfg(rust_analyzer)
+
+fn main() {
+    println!("cargo:rustc-check-cfg=cfg(rust_analyzer)");
+}