diff --git a/test/ASTMerge/Inputs/function1.c b/test/ASTMerge/Inputs/function1.c
new file mode 100644
index 0000000..b999123
--- /dev/null
+++ b/test/ASTMerge/Inputs/function1.c
@@ -0,0 +1,6 @@
+void f0(int);
+void f1(int, float);
+void f2();
+void f3(void);
+void f4(int, int);
+
diff --git a/test/ASTMerge/Inputs/function2.c b/test/ASTMerge/Inputs/function2.c
new file mode 100644
index 0000000..ad81c07
--- /dev/null
+++ b/test/ASTMerge/Inputs/function2.c
@@ -0,0 +1,6 @@
+typedef int Int;
+void f0(Int);
+void f1(Int, double);
+void f2(int, int);
+void f3(int);
+static void f4(float, float);
diff --git a/test/ASTMerge/function.c b/test/ASTMerge/function.c
new file mode 100644
index 0000000..581b6ec
--- /dev/null
+++ b/test/ASTMerge/function.c
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -emit-pch -o %t.1.ast %S/Inputs/function1.c
+// RUN: %clang_cc1 -emit-pch -o %t.2.ast %S/Inputs/function2.c
+// RUN: %clang_cc1 -ast-merge %t.1.ast -ast-merge %t.2.ast -fsyntax-only %s 2>&1 | FileCheck %s
+
+// CHECK: function2.c:3:6: error: external function 'f1' declared with incompatible types in different translation units ('void (Int, double)' vs. 'void (int, float)')
+// CHECK: function1.c:2:6: note: declared here with type 'void (int, float)'
+// CHECK: function2.c:5:6: error: external function 'f3' declared with incompatible types in different translation units ('void (int)' vs. 'void (void)')
+// CHECK: function1.c:4:6: note: declared here with type 'void (void)'
+// CHECK: 4 diagnostics generated