diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -1110,7 +1110,7 @@
           !Contexts.back().IsExpression && !Line.startsWith(TT_ObjCProperty) &&
           !Tok->isOneOf(TT_TypeDeclarationParen, TT_RequiresExpressionLParen) &&
           (!Tok->Previous ||
-           !Tok->Previous->isOneOf(tok::kw___attribute,
+           !Tok->Previous->isOneOf(tok::kw___attribute, TT_RequiresClause,
                                    TT_LeadingJavaAnnotation))) {
         Line.MightBeFunctionDecl = true;
       }
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -728,6 +728,16 @@
   BaseTokenCount = 26;
   TestRequires(__LINE__);
 
+  BaseCode = "template<typename T>\n"
+             "T foo();";
+  ConstrainedCode = "template<typename T>\n"
+                    "  requires(Foo<T>)\n"
+                    "T foo();";
+  BaseTokenCount = 11;
+  RequiresTokenCount = 7;
+  PrefixTokenCount = 5;
+  TestRequires(__LINE__);
+
   BaseCode = "template<typename T>\n"
              "Bar(T) -> Bar<typename T::I>;";
   ConstrainedCode = "template<typename T>\n"