3 files changed, 40 insertions, 0 deletions
diff --git a/clang/test/ASTMerge/Inputs/namespace1.cpp b/clang/test/ASTMerge/Inputs/namespace1.cpp
new file mode 100644
index 00000000000..1ff84f3111c
--- /dev/null
+++ b/clang/test/ASTMerge/Inputs/namespace1.cpp
@@ -0,0 +1,17 @@
+// Merge success
+namespace N1 {
+  int x;
+}
+
+// Merge multiple namespaces
+namespace N2 {
+  extern int x;
+}
+namespace N2 {
+  extern float y;
+}
+
+// Merge namespace with conflict
+namespace N3 {
+  extern float z;
+}
diff --git a/clang/test/ASTMerge/Inputs/namespace2.cpp b/clang/test/ASTMerge/Inputs/namespace2.cpp
new file mode 100644
index 00000000000..80429f700b1
--- /dev/null
+++ b/clang/test/ASTMerge/Inputs/namespace2.cpp
@@ -0,0 +1,17 @@
+// Merge success
+namespace N1 {
+  extern int x0;
+}
+
+// Merge multiple namespaces
+namespace N2 {
+  extern int x;
+}
+namespace N2 {
+  extern float y;
+}
+
+// Merge namespace with conflict
+namespace N3 {
+  extern double z;
+}
diff --git a/clang/test/ASTMerge/namespace.cpp b/clang/test/ASTMerge/namespace.cpp
new file mode 100644
index 00000000000..6c46f0aa1d9
--- /dev/null
+++ b/clang/test/ASTMerge/namespace.cpp
@@ -0,0 +1,6 @@
+// RUN: %clang_cc1 -emit-pch -o %t.1.ast %S/Inputs/namespace1.cpp
+// RUN: %clang_cc1 -emit-pch -o %t.2.ast %S/Inputs/namespace2.cpp
+// RUN: %clang_cc1 -ast-merge %t.1.ast -ast-merge %t.2.ast -fsyntax-only %s 2>&1 | FileCheck %s
+
+// CHECK: namespace2.cpp:16:17: error: external variable 'z' declared with incompatible types in different translation units ('double' vs. 'float')
+// CHECK: namespace1.cpp:16:16: note: declared here with type 'float'