diff --git a/clang/lib/Format/UnwrappedLineFormatter.cpp b/clang/lib/Format/UnwrappedLineFormatter.cpp
index 16fa2e7b50f1c3..dbf1e4cbbf6a31 100644
--- a/clang/lib/Format/UnwrappedLineFormatter.cpp
+++ b/clang/lib/Format/UnwrappedLineFormatter.cpp
@@ -312,10 +312,15 @@ class LineJoiner {
               break;
 
           // Check if the found line starts a record.
-          for (const FormatToken *RecordTok = (*J)->Last; RecordTok;
-               RecordTok = RecordTok->Previous)
-            if (RecordTok->is(tok::l_brace))
-              return isRecordLBrace(*RecordTok);
+          const FormatToken *LastNonComment = (*J)->Last;
+          assert(LastNonComment);
+          if (LastNonComment->is(tok::comment)) {
+            LastNonComment = LastNonComment->getPreviousNonComment();
+            // There must be another token (usually `{`), because we chose a
+            // line that has a smaller level.
+            assert(LastNonComment);
+          }
+          return isRecordLBrace(*LastNonComment);
         }
       }
 
diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 6e5dd3284633c4..73503696741a77 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -3809,6 +3809,18 @@ TEST_F(FormatTest, FormatsNamespaces) {
                "  }\n"
                "} // namespace\n",
                ShortInlineFunctions);
+  verifyFormat("namespace { /* comment */\n"
+               "  void f() {\n"
+               "    return;\n"
+               "  }\n"
+               "} // namespace\n",
+               ShortInlineFunctions);
+  verifyFormat("namespace { // comment\n"
+               "  void f() {\n"
+               "    return;\n"
+               "  }\n"
+               "} // namespace\n",
+               ShortInlineFunctions);
   verifyFormat("namespace {\n"
                "  int some_int;\n"
                "  void f() {\n"
@@ -3828,6 +3840,18 @@ TEST_F(FormatTest, FormatsNamespaces) {
                "  };\n"
                "} // namespace\n",
                ShortInlineFunctions);
+  verifyFormat("namespace {\n"
+               "  class X { /* comment */\n"
+               "    void f() { return; }\n"
+               "  };\n"
+               "} // namespace\n",
+               ShortInlineFunctions);
+  verifyFormat("namespace {\n"
+               "  class X { // comment\n"
+               "    void f() { return; }\n"
+               "  };\n"
+               "} // namespace\n",
+               ShortInlineFunctions);
   verifyFormat("namespace {\n"
                "  struct X {\n"
                "    void f() { return; }\n"