diff --git a/clang/lib/Format/NamespaceEndCommentsFixer.cpp b/clang/lib/Format/NamespaceEndCommentsFixer.cpp
--- a/clang/lib/Format/NamespaceEndCommentsFixer.cpp
+++ b/clang/lib/Format/NamespaceEndCommentsFixer.cpp
@@ -51,7 +51,9 @@
     }
 
     Tok = FirstNSTok;
-    while (Tok && !Tok->is(tok::l_brace)) {
+    while (Tok && !Tok->is(tok::l_brace) &&
+           (Tok->Tok.isAnyIdentifier() || Tok->is(tok::coloncolon) ||
+            Tok->is(tok::kw_inline))) {
       name += Tok->TokenText;
       if (Tok->is(tok::kw_inline))
         name += " ";
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
@@ -2597,10 +2597,12 @@
     parseParens();
   } else {
     while (FormatTok->isOneOf(tok::identifier, tok::coloncolon, tok::kw_inline,
-                              tok::l_square, tok::period) ||
+                              tok::l_square, tok::period, tok::l_paren) ||
            (Style.isCSharp() && FormatTok->is(tok::kw_union)))
       if (FormatTok->is(tok::l_square))
         parseSquare();
+      else if (FormatTok->is(tok::l_paren))
+        parseParens();
       else
         nextToken();
   }
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -3738,6 +3738,36 @@
                "void f() { f(); }\n"
                "}",
                LLVMWithNoNamespaceFix);
+  verifyFormat("#define M(x) x##x\n"
+               "namespace M(x) {\n"
+               "class A {};\n"
+               "void f() { f(); }\n"
+               "}",
+               LLVMWithNoNamespaceFix);
+  verifyFormat("#define M(x) x##x\n"
+               "namespace N::inline M(x) {\n"
+               "class A {};\n"
+               "void f() { f(); }\n"
+               "}",
+               LLVMWithNoNamespaceFix);
+  verifyFormat("#define M(x) x##x\n"
+               "namespace M(x)::inline N {\n"
+               "class A {};\n"
+               "void f() { f(); }\n"
+               "}",
+               LLVMWithNoNamespaceFix);
+  verifyFormat("#define M(x) x##x\n"
+               "namespace N::M(x) {\n"
+               "class A {};\n"
+               "void f() { f(); }\n"
+               "}",
+               LLVMWithNoNamespaceFix);
+  verifyFormat("#define M(x) x##x\n"
+               "namespace M::N(x) {\n"
+               "class A {};\n"
+               "void f() { f(); }\n"
+               "}",
+               LLVMWithNoNamespaceFix);
   verifyFormat("namespace N::inline D {\n"
                "class A {};\n"
                "void f() { f(); }\n"
diff --git a/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp b/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp
--- a/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp
+++ b/clang/unittests/Format/NamespaceEndCommentsFixerTest.cpp
@@ -68,6 +68,27 @@
                                     "int i;\n"
                                     "int j;\n"
                                     "}"));
+  // FIXME: Expand macro for namepsace name.
+  EXPECT_EQ("#define M(x) x##x\n"
+            "namespace M(x) {\n"
+            "int i;\n"
+            "int j;\n"
+            "}// namespace",
+            fixNamespaceEndComments("#define M(x) x##x\n"
+                                    "namespace M(x) {\n"
+                                    "int i;\n"
+                                    "int j;\n"
+                                    "}"));
+  EXPECT_EQ("#define M(x) x##x\n"
+            "namespace A::M(x) {\n"
+            "int i;\n"
+            "int j;\n"
+            "}// namespace A::M",
+            fixNamespaceEndComments("#define M(x) x##x\n"
+                                    "namespace A::M(x) {\n"
+                                    "int i;\n"
+                                    "int j;\n"
+                                    "}"));
   EXPECT_EQ("inline namespace A {\n"
             "int i;\n"
             "int j;\n"