Index: clang/lib/Format/UnwrappedLineParser.cpp
===================================================================
--- clang/lib/Format/UnwrappedLineParser.cpp
+++ clang/lib/Format/UnwrappedLineParser.cpp
@@ -2995,7 +2995,6 @@
 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
@@ -3024,7 +3023,6 @@
 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);
 
Index: clang/unittests/Format/FormatTest.cpp
===================================================================
--- clang/unittests/Format/FormatTest.cpp
+++ clang/unittests/Format/FormatTest.cpp
@@ -23808,6 +23808,15 @@
 
   verifyFormat("template <typename T>\n"
                "concept C = [] && requires(T t) { typename T::size_type; };");
+
+  verifyFormat("template <typename T>\n"
+               "concept C =\n"
+               "#if X\n"
+               "    A &&\n"
+               "#else\n"
+               "    B &&\n"
+               "#endif\n"
+               "    requires C2<T>;");
 }
 
 TEST_F(FormatTest, RequiresClausesPositions) {