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
@@ -1439,7 +1439,7 @@
       return;
     case tok::kw_requires:
       parseRequires();
-      break;
+      return;
     case tok::kw_enum:
       // Ignore if this is part of "template <enum ...".
       if (Previous && Previous->is(tok::less)) {
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
@@ -3556,6 +3556,11 @@
                "struct b_struct {};\n"
                "} // namespace B\n",
                Style);
+  verifyFormat("template <int I> constexpr void foo requires(I == 42) {}\n"
+               "namespace ns {\n"
+               "void foo() {}\n"
+               "} // namespace ns\n",
+               Style);
 }
 
 TEST_F(FormatTest, NamespaceMacros) {