Index: lib/Format/ContinuationIndenter.h
===================================================================
--- lib/Format/ContinuationIndenter.h
+++ lib/Format/ContinuationIndenter.h
@@ -208,7 +208,8 @@
         NoLineBreakInOperand(false), LastOperatorWrapped(true),
         ContainsLineBreak(false), ContainsUnwrappedBuilder(false),
         AlignColons(true), ObjCSelectorNameFound(false),
-        HasMultipleNestedBlocks(false), NestedBlockInlined(false) {}
+        HasMultipleNestedBlocks(false), NestedBlockInlined(false),
+        IsInsideObjCArrayLiteral(false) {}
 
   /// \brief The position to which a specific parenthesis level needs to be
   /// indented.
@@ -318,6 +319,10 @@
   /// "function" in JavaScript) is not wrapped to a new line.
   bool NestedBlockInlined : 1;
 
+  /// \brief \c true if the current \c ParenState represents an Objective-C
+  /// array literal.
+  bool IsInsideObjCArrayLiteral : 1;
+
   bool operator<(const ParenState &Other) const {
     if (Indent != Other.Indent)
       return Indent < Other.Indent;
Index: lib/Format/ContinuationIndenter.cpp
===================================================================
--- lib/Format/ContinuationIndenter.cpp
+++ lib/Format/ContinuationIndenter.cpp
@@ -1285,6 +1285,9 @@
   State.Stack.back().NestedBlockIndent = NestedBlockIndent;
   State.Stack.back().BreakBeforeParameter = BreakBeforeParameter;
   State.Stack.back().HasMultipleNestedBlocks = Current.BlockParameterCount > 1;
+  State.Stack.back().IsInsideObjCArrayLiteral =
+      Current.is(TT_ArrayInitializerLSquare) && Current.Previous &&
+      Current.Previous->is(tok::at);
 }
 
 void ContinuationIndenter::moveStatePastScopeCloser(LineState &State) {
@@ -1578,6 +1581,11 @@
     // likely want to terminate the string before any line breaking is done.
     if (Current.IsUnterminatedLiteral)
       return nullptr;
+    // Don't break string literals inside Objective-C array literals (doing so
+    // raises the warning -Wobjc-string-concatenation).
+    if (State.Stack.back().IsInsideObjCArrayLiteral) {
+      return nullptr;
+    }
 
     StringRef Text = Current.TokenText;
     StringRef Prefix;
Index: unittests/Format/FormatTestObjC.cpp
===================================================================
--- unittests/Format/FormatTestObjC.cpp
+++ unittests/Format/FormatTestObjC.cpp
@@ -975,6 +975,12 @@
   verifyFormat("[someFunction someLooooooooooooongParameter:@[\n"
                "  NSBundle.mainBundle.infoDictionary[@\"a\"]\n"
                "]];");
+  Style.ColumnLimit = 20;
+  // We can't break string literals inside NSArray literals
+  // (that raises -Wobjc-string-concatenation).
+  verifyFormat("NSArray *foo = @[\n"
+               "  @\"aaaaaaaaaaaaaaaaaaaaaaaaaa\"\n"
+               "];\n");
 }
 } // end namespace
 } // end namespace format