diff --git a/compiler/rustc_mir_transform/src/liveness.rs b/compiler/rustc_mir_transform/src/liveness.rs
index f7dc703560245..d9dd7f9c5b195 100644
--- a/compiler/rustc_mir_transform/src/liveness.rs
+++ b/compiler/rustc_mir_transform/src/liveness.rs
@@ -72,6 +72,11 @@ pub(crate) fn check_liveness<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Den
         return DenseBitSet::new_empty(0);
     }
 
+    // Don't run unused pass for items generated by foreign macros
+    if tcx.def_span(parent).in_external_macro(tcx.sess.source_map()) {
+        return DenseBitSet::new_empty(0);
+    }
+
     let mut body = &*tcx.mir_promoted(def_id).0.borrow();
     let mut body_mem;
 
diff --git a/tests/ui/liveness/auxiliary/aux_issue_147648.rs b/tests/ui/liveness/auxiliary/aux_issue_147648.rs
new file mode 100644
index 0000000000000..ccb5ad6b8fc09
--- /dev/null
+++ b/tests/ui/liveness/auxiliary/aux_issue_147648.rs
@@ -0,0 +1,7 @@
+#[macro_export]
+macro_rules! unused_assign {
+    ($x:ident) => {
+        let mut $x = 1;
+        $x = 2;
+    };
+}
diff --git a/tests/ui/liveness/unused-assignments-from-macro-147648.rs b/tests/ui/liveness/unused-assignments-from-macro-147648.rs
new file mode 100644
index 0000000000000..c32c281538b44
--- /dev/null
+++ b/tests/ui/liveness/unused-assignments-from-macro-147648.rs
@@ -0,0 +1,10 @@
+//@ check-pass
+//@ aux-build:aux_issue_147648.rs
+
+#![deny(unused_assignments)]
+
+extern crate aux_issue_147648;
+
+fn main() {
+    aux_issue_147648::unused_assign!(y);
+}