Index: clang/include/clang/Basic/DiagnosticSemaKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -2999,6 +2999,10 @@
 def warn_objc_string_literal_comparison : Warning<
   "direct comparison of a string literal has undefined behavior">,
   InGroup<ObjCStringComparison>;
+def warn_concatenated_literal_array_init : Warning<
+  "concatenated literal in a string array initialization - "
+  "possibly missing a comma">,
+  InGroup<DiagGroup<"string-concatenation">>;
 def warn_concatenated_nsarray_literal : Warning<
   "concatenated NSString literal for an NSArray expression - "
   "possibly missing a comma">,
Index: clang/lib/Sema/SemaExpr.cpp
===================================================================
--- clang/lib/Sema/SemaExpr.cpp
+++ clang/lib/Sema/SemaExpr.cpp
@@ -6907,6 +6907,19 @@
         << DIE->getSourceRange();
       Diag(InitArgList[I]->getBeginLoc(), diag::note_designated_init_mixed)
         << InitArgList[I]->getSourceRange();
+    } else if (StringLiteral *SL = dyn_cast<StringLiteral>(InitArgList[I])) {
+      unsigned numConcat = SL->getNumConcatenated();
+      // Diagnose missing comma in string array initialization.
+      if (numConcat > 1) {
+        bool hasMacro = false;
+        for (unsigned i = 0; i < numConcat; ++i)
+          if (SL->getStrTokenLoc(i).isMacroID()) {
+            hasMacro = true;
+            break;
+          }
+        if (!hasMacro)
+          Diag(SL->getBeginLoc(), diag::warn_concatenated_literal_array_init);
+      }
     }
   }
 
Index: clang/test/Sema/string-concat.c
===================================================================
--- /dev/null
+++ clang/test/Sema/string-concat.c
@@ -9,13 +9,7 @@
     "optional",
     "packaged_task" // expected-warning{{concatenated literal in a string array initialization - possibly missing a comma}}
     "promise",
-    "shared_future",
-    "shared_lock",
-    "shared_ptr",
-    "thread",
-    "unique_ptr",
-    "unique_lock",
-    "weak_ptr",
+    "shared_future"
 };
 
 const char *test2[] = {"basic_filebuf",
@@ -32,10 +26,30 @@
                        "future", "optional",
                        "packaged_task", "promise"};
 
+const char *test5[] = {"basic_filebuf", "future" "optional", "packaged_task"}; // expected-warning{{concatenated literal in a string array initialization - possibly missing a comma}}
+
+
+// Do not warn for macros.
+
 #define BASIC_IOS "basic_ios"
 #define FUTURE "future"
-const char *test5[] = {"basic_filebuf", BASIC_IOS // expected-warning{{concatenated literal in a string array initialization - possibly missing a comma}}
+const char *test6[] = {"basic_filebuf", BASIC_IOS
                         FUTURE, "optional",
                        "packaged_task", "promise"};
 
-const char *test6[] = {"basic_filebuf", "future" "optional", "packaged_task"}; // expected-warning{{concatenated literal in a string array initialization - possibly missing a comma}}
+#define FOO(xx) xx "_normal", \
+                xx "_movable",
+
+const char *test7[] = {"basic_filebuf",
+                       "basic_ios"
+                       FOO("future")
+                       "optional",
+                       "packaged_task"};
+
+#define BAR(name) #name "_normal"
+
+const char *test8[] = {"basic_filebuf",
+                       "basic_ios"
+                       BAR(future),
+                       "optional",
+                       "packaged_task"};