Index: lib/Index/USRGeneration.cpp
===================================================================
--- lib/Index/USRGeneration.cpp
+++ lib/Index/USRGeneration.cpp
@@ -816,6 +816,25 @@
       T = VT->getElementType();
       continue;
     }
+    if (const auto *const AT = dyn_cast<ArrayType>(T)) {
+      Out << '{';
+      switch (AT->getSizeModifier()) {
+      case ArrayType::Static:
+        Out << 's';
+        break;
+      case ArrayType::Star:
+        Out << '*';
+        break;
+      case ArrayType::Normal:
+        Out << 'n';
+        break;
+      }
+      if (const auto *const CAT = dyn_cast<ConstantArrayType>(T))
+        Out << CAT->getSize();
+
+      T = AT->getElementType();
+      continue;
+    }
 
     // Unhandled type.
     Out << ' ';
Index: test/Index/USR/array-type.cpp
===================================================================
--- /dev/null
+++ test/Index/USR/array-type.cpp
@@ -0,0 +1,11 @@
+// RUN: c-index-test core -print-source-symbols -- %s | FileCheck %s
+
+// Function template specializations differing in array type parameter should have unique USRs.
+
+template<class buffer> void foo(buffer);
+// CHECK: {{[0-9]+}}:17 | function(Gen,TS)/C++ | foo | c:@F@foo<#{n16C>#*C# | __Z3fooIA16_cEvT_ | Decl,RelSpecialization | rel: 1
+template<> void foo<char[16]>(char[16]);
+// CHECK: {{[0-9]+}}:17 | function(Gen,TS)/C++ | foo | c:@F@foo<#{n32C>#*C# | __Z3fooIA32_cEvT_ | Decl,RelSpecialization | rel: 1
+template<> void foo<char[32]>(char[32]);
+// CHECK: {{[0-9]+}}:17 | function(Gen,TS)/C++ | foo | c:@F@foo<#{n64C>#*C# | __Z3fooIA64_cEvT_ | Decl,RelSpecialization | rel: 1
+template<> void foo<char[64]>(char[64]);