Index: clang/lib/Format/UnwrappedLineParser.cpp
===================================================================
--- clang/lib/Format/UnwrappedLineParser.cpp
+++ clang/lib/Format/UnwrappedLineParser.cpp
@@ -1881,7 +1881,7 @@
         }
       }
 
-      if (FormatTok->is(Keywords.kw_interface)) {
+      if (!Style.isCpp() && FormatTok->is(Keywords.kw_interface)) {
         if (parseStructLike())
           return;
         break;
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -25429,6 +25429,14 @@
   verifyFormat("auto x = 5s .count() == 5;");
 }
 
+TEST_F(FormatTest, InterfaceAsClassMemberName) {
+  constexpr StringRef Code("class Foo {\n"
+                           "  int interface;\n"
+                           "  Foo::Foo(int iface) : interface{iface} {}\n"
+                           "}\n");
+  verifyFormat(Code);
+}
+
 } // namespace
 } // namespace test
 } // namespace format