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
@@ -2994,7 +2994,6 @@
 void UnwrappedLineParser::parseRequiresClause(FormatToken *RequiresToken) {
   assert(FormatTok->getPreviousNonComment() == RequiresToken);
   assert(RequiresToken->is(tok::kw_requires) && "'requires' expected");
-  assert(RequiresToken->getType() == TT_Unknown);
 
   // If there is no previous token, we are within a requires expression,
   // otherwise we will always have the template or function declaration in front
@@ -3023,7 +3022,6 @@
 void UnwrappedLineParser::parseRequiresExpression(FormatToken *RequiresToken) {
   assert(FormatTok->getPreviousNonComment() == RequiresToken);
   assert(RequiresToken->is(tok::kw_requires) && "'requires' expected");
-  assert(RequiresToken->getType() == TT_Unknown);
 
   RequiresToken->setFinalizedType(TT_RequiresExpression);
 
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
@@ -24053,6 +24053,13 @@
                "    return number_zero_v<T>;\n"
                "  }\n"
                "};");
+
+  // Not a clause, but we once hit an assert.
+  verifyFormat("#if 0\n"
+               "#else\n"
+               "foo();\n"
+               "#endif\n"
+               "bar(requires);");
 }
 
 TEST_F(FormatTest, StatementAttributeLikeMacros) {