Index: clang/lib/Format/TokenAnnotator.cpp
===================================================================
--- clang/lib/Format/TokenAnnotator.cpp
+++ clang/lib/Format/TokenAnnotator.cpp
@@ -2869,7 +2869,8 @@
     // space between keywords and paren e.g. "using ("
     if (Right.is(tok::l_paren))
       if (Left.is(tok::kw_using))
-        return spaceRequiredBeforeParens(Left);
+        return Style.SpaceBeforeParens == FormatStyle::SBPO_ControlStatements ||
+               spaceRequiredBeforeParens(Right);
   } else if (Style.Language == FormatStyle::LK_JavaScript) {
     if (Left.is(TT_JsFatArrow))
       return true;
Index: clang/unittests/Format/FormatTestCSharp.cpp
===================================================================
--- clang/unittests/Format/FormatTestCSharp.cpp
+++ clang/unittests/Format/FormatTestCSharp.cpp
@@ -235,20 +235,46 @@
   Style.SpaceBeforeParens = FormatStyle::SBPO_Always;
   verifyFormat("public void foo () {\n"
                "  using (StreamWriter sw = new StreamWriter (filenameA)) {}\n"
+               "  using () {}\n"
                "}",
                Style);
 
+  // Ensure clang-format affects top-level snippets correctly.
   verifyFormat("using (StreamWriter sw = new StreamWriter (filenameB)) {}",
                Style);
 
   Style.SpaceBeforeParens = FormatStyle::SBPO_Never;
   verifyFormat("public void foo() {\n"
                "  using(StreamWriter sw = new StreamWriter(filenameB)) {}\n"
+               "  using() {}\n"
                "}",
                Style);
 
+  // Ensure clang-format affects top-level snippets correctly.
   verifyFormat("using(StreamWriter sw = new StreamWriter(filenameB)) {}",
                Style);
+
+  Style.SpaceBeforeParens = FormatStyle::SBPO_ControlStatements;
+  verifyFormat("public void foo() {\n"
+               "  using (StreamWriter sw = new StreamWriter(filenameA)) {}\n"
+               "  using () {}\n"
+               "}",
+               Style);
+
+  // Ensure clang-format affects top-level snippets correctly.
+  verifyFormat("using (StreamWriter sw = new StreamWriter(filenameB)) {}",
+               Style);
+
+  Style.SpaceBeforeParens = FormatStyle::SBPO_NonEmptyParentheses;
+  verifyFormat("public void foo() {\n"
+               "  using (StreamWriter sw = new StreamWriter (filenameA)) {}\n"
+               "  using() {}\n"
+               "}",
+               Style);
+
+  // Ensure clang-format affects top-level snippets correctly.
+  verifyFormat("using (StreamWriter sw = new StreamWriter (filenameB)) {}",
+               Style);
 }
 
 TEST_F(FormatTestCSharp, CSharpRegions) {