diff --git a/clang/include/clang/Basic/DiagnosticSemaKinds.td b/clang/include/clang/Basic/DiagnosticSemaKinds.td
index 9fa66db13916..e02271c90231 100644
--- a/clang/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/clang/include/clang/Basic/DiagnosticSemaKinds.td
@@ -3801,34 +3801,14 @@ def note_template_parameter_pack_here : Note<
   "previous %select{template type|non-type template|template template}0 "
   "parameter%select{| pack}1 declared here">;
   
-def err_unexpanded_parameter_pack_0 : Error<
+def err_unexpanded_parameter_pack : Error<
   "%select{expression|base type|declaration type|data member type|bit-field "
   "size|static assertion|fixed underlying type|enumerator value|"
   "using declaration|friend declaration|qualifier|initializer|default argument|"
   "non-type template parameter type|exception type|partial specialization|"
-  "__if_exists name|__if_not_exists name|lambda|block}0 "
-  "contains an unexpanded parameter pack">;
-def err_unexpanded_parameter_pack_1 : Error<
-  "%select{expression|base type|declaration type|data member type|bit-field "
-  "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration|friend declaration|qualifier|initializer|default argument|"
-  "non-type template parameter type|exception type|partial specialization|"
-  "__if_exists name|__if_not_exists name|lambda|block}0 "
-  "contains unexpanded parameter pack %1">;
-def err_unexpanded_parameter_pack_2 : Error<
-  "%select{expression|base type|declaration type|data member type|bit-field "
-  "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration|friend declaration|qualifier|initializer|default argument|"
-  "non-type template parameter type|exception type|partial specialization|"
-  "__if_exists name|__if_not_exists name|lambda|block}0 "
-  "contains unexpanded parameter packs %1 and %2">;
-def err_unexpanded_parameter_pack_3_or_more : Error<
-  "%select{expression|base type|declaration type|data member type|bit-field "
-  "size|static assertion|fixed underlying type|enumerator value|"
-  "using declaration|friend declaration|qualifier|initializer|default argument|"
-  "non-type template parameter type|exception type|partial specialization|"
-  "__if_exists name|__if_not_exists name|lambda|block}0 "
-  "contains unexpanded parameter packs %1, %2, ...">;
+  "__if_exists name|__if_not_exists name|lambda|block}0 contains"
+  "%plural{0: an|:}1 unexpanded parameter pack"
+  "%plural{0:|1: %2|2:s %2 and %3|:s %2, %3, ...}1">;
 
 def err_pack_expansion_without_parameter_packs : Error<
   "pack expansion does not contain any unexpanded parameter packs">;
@@ -6878,29 +6858,18 @@ def warn_case_empty_range : Warning<"empty case range specified">;
 def warn_missing_case_for_condition :
   Warning<"no case matching constant switch condition '%0'">;
 
-def warn_def_missing_case1 : Warning<
-  "enumeration value %0 not explicitly handled in switch">,
-  InGroup<SwitchEnum>, DefaultIgnore;
-def warn_def_missing_case2 : Warning<
-  "enumeration values %0 and %1 not explicitly handled in switch">,
-  InGroup<SwitchEnum>, DefaultIgnore;
-def warn_def_missing_case3 : Warning<
-  "enumeration values %0, %1, and %2 not explicitly handled in switch">,
-  InGroup<SwitchEnum>, DefaultIgnore;
-def warn_def_missing_cases : Warning<
-  "%0 enumeration values not explicitly handled in switch: %1, %2, %3...">,
+def warn_def_missing_case : Warning<"%plural{"
+  "1:enumeration value %1 not explicitly handled in switch|"
+  "2:enumeration values %1 and %2 not explicitly handled in switch|"
+  "3:enumeration values %1, %2, and %3 not explicitly handled in switch|"
+  ":%0 enumeration values not explicitly handled in switch: %1, %2, %3...}0">,
   InGroup<SwitchEnum>, DefaultIgnore;
 
-def warn_missing_case1 : Warning<"enumeration value %0 not handled in switch">,
-  InGroup<Switch>;
-def warn_missing_case2 : Warning<
-  "enumeration values %0 and %1 not handled in switch">,
-  InGroup<Switch>;
-def warn_missing_case3 : Warning<
-  "enumeration values %0, %1, and %2 not handled in switch">,
-  InGroup<Switch>;
-def warn_missing_cases : Warning<
-  "%0 enumeration values not handled in switch: %1, %2, %3...">,
+def warn_missing_case : Warning<"%plural{"
+  "1:enumeration value %1 not handled in switch|"
+  "2:enumeration values %1 and %2 not handled in switch|"
+  "3:enumeration values %1, %2, and %3 not handled in switch|"
+  ":%0 enumeration values not handled in switch: %1, %2, %3...}0">,
   InGroup<Switch>;
 
 def warn_unannotated_fallthrough : Warning<
diff --git a/clang/lib/Sema/SemaStmt.cpp b/clang/lib/Sema/SemaStmt.cpp
index f923f61ce61c..0ac9c893b3ee 100644
--- a/clang/lib/Sema/SemaStmt.cpp
+++ b/clang/lib/Sema/SemaStmt.cpp
@@ -1133,29 +1133,15 @@ Sema::ActOnFinishSwitchStmt(SourceLocation SwitchLoc, Stmt *Switch,
         Diag(TheDefaultStmt->getDefaultLoc(), diag::warn_unreachable_default);
 
       // Produce a nice diagnostic if multiple values aren't handled.
-      switch (UnhandledNames.size()) {
-      case 0: break;
-      case 1:
-        Diag(CondExpr->getExprLoc(), TheDefaultStmt
-          ? diag::warn_def_missing_case1 : diag::warn_missing_case1)
-          << UnhandledNames[0];
-        break;
-      case 2:
-        Diag(CondExpr->getExprLoc(), TheDefaultStmt
-          ? diag::warn_def_missing_case2 : diag::warn_missing_case2)
-          << UnhandledNames[0] << UnhandledNames[1];
-        break;
-      case 3:
-        Diag(CondExpr->getExprLoc(), TheDefaultStmt
-          ? diag::warn_def_missing_case3 : diag::warn_missing_case3)
-          << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
-        break;
-      default:
-        Diag(CondExpr->getExprLoc(), TheDefaultStmt
-          ? diag::warn_def_missing_cases : diag::warn_missing_cases)
-          << (unsigned)UnhandledNames.size()
-          << UnhandledNames[0] << UnhandledNames[1] << UnhandledNames[2];
-        break;
+      if (!UnhandledNames.empty()) {
+        DiagnosticBuilder DB = Diag(CondExpr->getExprLoc(),
+                                    TheDefaultStmt ? diag::warn_def_missing_case
+                                                   : diag::warn_missing_case)
+                               << (int)UnhandledNames.size();
+
+        for (size_t I = 0, E = std::min(UnhandledNames.size(), (size_t)3);
+             I != E; ++I)
+          DB << UnhandledNames[I];
       }
 
       if (!hasCasesNotInSwitch)
diff --git a/clang/lib/Sema/SemaTemplateVariadic.cpp b/clang/lib/Sema/SemaTemplateVariadic.cpp
index e4fab71d995b..fd3ba3549b4c 100644
--- a/clang/lib/Sema/SemaTemplateVariadic.cpp
+++ b/clang/lib/Sema/SemaTemplateVariadic.cpp
@@ -251,15 +251,10 @@ Sema::DiagnoseUnexpandedParameterPacks(SourceLocation Loc,
       Locations.push_back(Unexpanded[I].second);
   }
 
-  DiagnosticBuilder DB
-    = Names.size() == 0? Diag(Loc, diag::err_unexpanded_parameter_pack_0)
-                           << (int)UPPC
-    : Names.size() == 1? Diag(Loc, diag::err_unexpanded_parameter_pack_1)
-                           << (int)UPPC << Names[0]
-    : Names.size() == 2? Diag(Loc, diag::err_unexpanded_parameter_pack_2)
-                           << (int)UPPC << Names[0] << Names[1]
-    : Diag(Loc, diag::err_unexpanded_parameter_pack_3_or_more)
-        << (int)UPPC << Names[0] << Names[1];
+  DiagnosticBuilder DB = Diag(Loc, diag::err_unexpanded_parameter_pack)
+                         << (int)UPPC << (int)Names.size();
+  for (size_t I = 0, E = std::min(Names.size(), (size_t)2); I != E; ++I)
+    DB << Names[I];
 
   for (unsigned I = 0, N = Locations.size(); I != N; ++I)
     DB << SourceRange(Locations[I]);