diff --git a/crates/build-rs-test-lib/build.rs b/crates/build-rs-test-lib/build.rs
index 1167a3490..eff04806a 100644
--- a/crates/build-rs-test-lib/build.rs
+++ b/crates/build-rs-test-lib/build.rs
@@ -10,7 +10,6 @@ fn smoke_test_inputs() {
     use build_rs::input::*;
     dbg!(cargo());
     dbg!(cargo_cfg("careful"));
-    dbg!(cargo_cfg_debug_assertions());
     #[cfg(feature = "unstable")]
     dbg!(cargo_cfg_fmt_debug());
     #[cfg(feature = "unstable")]
diff --git a/crates/build-rs/src/input.rs b/crates/build-rs/src/input.rs
index 6f564f8c6..112aa5fed 100644
--- a/crates/build-rs/src/input.rs
+++ b/crates/build-rs/src/input.rs
@@ -109,6 +109,11 @@ mod cfg {
     }
 
     /// If we are compiling with debug assertions enabled.
+    ///
+    /// Build scripts are not passed this cfg because
+    /// this cfg is always true and misleading.
+    /// That is because Cargo queries rustc without any profile settings.
+    #[cfg(any())]
     #[track_caller]
     pub fn cargo_cfg_debug_assertions() -> bool {
         is_present("CARGO_CFG_DEBUG_ASSERTIONS")