Check in LLVM r95781.
diff --git a/test/Preprocessor/macro_disable4.c b/test/Preprocessor/macro_disable4.c
new file mode 100644
index 0000000..820858c
--- /dev/null
+++ b/test/Preprocessor/macro_disable4.c
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -P -E %s | grep 'int f(void)'
+// PR1820
+
+#define f(x) h(x
+#define h(x) x(void) 
+extern int f(f));