diff --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -2216,7 +2216,7 @@
     parseParens();
   } else {
     while (FormatTok->isOneOf(tok::identifier, tok::coloncolon, tok::kw_inline,
-                              tok::l_square)) {
+                              tok::l_square, tok::period)) {
       if (FormatTok->is(tok::l_square))
         parseSquare();
       else
diff --git a/clang/unittests/Format/FormatTestCSharp.cpp b/clang/unittests/Format/FormatTestCSharp.cpp
--- a/clang/unittests/Format/FormatTestCSharp.cpp
+++ b/clang/unittests/Format/FormatTestCSharp.cpp
@@ -1314,5 +1314,60 @@
                Style);
 }
 
+TEST_F(FormatTestCSharp, NamespaceIndentation) {
+  FormatStyle Style = getMicrosoftStyle(FormatStyle::LK_CSharp);
+  Style.NamespaceIndentation = FormatStyle::NI_None;
+
+  verifyFormat("namespace A\n"
+               "{\n"
+               "public interface Name1\n"
+               "{\n"
+               "}\n"
+               "}\n",
+               Style);
+
+  verifyFormat("namespace A.B\n"
+               "{\n"
+               "public interface Name1\n"
+               "{\n"
+               "}\n"
+               "}\n",
+               Style);
+
+  Style.NamespaceIndentation = FormatStyle::NI_Inner;
+
+  verifyFormat("namespace A\n"
+               "{\n"
+               "namespace B\n"
+               "{\n"
+               "    public interface Name1\n"
+               "    {\n"
+               "    }\n"
+               "}\n"
+               "}\n",
+               Style);
+
+  Style.NamespaceIndentation = FormatStyle::NI_All;
+
+  verifyFormat("namespace A.B\n"
+               "{\n"
+               "    public interface Name1\n"
+               "    {\n"
+               "    }\n"
+               "}\n",
+               Style);
+
+  verifyFormat("namespace A\n"
+               "{\n"
+               "    namespace B\n"
+               "    {\n"
+               "        public interface Name1\n"
+               "        {\n"
+               "        }\n"
+               "    }\n"
+               "}\n",
+               Style);
+}
+
 } // namespace format
 } // end namespace clang