diff --git a/test/core.jl b/test/core.jl
index ee4605ff60704..b3dd90d9bba49 100644
--- a/test/core.jl
+++ b/test/core.jl
@@ -4469,3 +4469,10 @@ let
     k(x) = (k = x; k)
     @test k(1) == 1
 end
+
+# PR #18054: compilation of cfunction leaves IRBuilder in bad state,
+#            causing heap-use-after-free when compiling f18054
+function f18054()
+    return Cint(0)
+end
+cfunction(f18054, Cint, ())