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
@@ -1690,8 +1690,8 @@
         if (!Tok)
           return false;
 
-        if (Tok->isOneOf(tok::kw_class, tok::kw_enum, tok::kw_concept,
-                         tok::kw_struct, tok::kw_using)) {
+        if (Tok->isOneOf(tok::kw_class, tok::kw_enum, tok::kw_struct,
+                         tok::kw_using)) {
           return false;
         }
 
diff --git a/clang/lib/Format/UnwrappedLineParser.h b/clang/lib/Format/UnwrappedLineParser.h
--- a/clang/lib/Format/UnwrappedLineParser.h
+++ b/clang/lib/Format/UnwrappedLineParser.h
@@ -158,7 +158,6 @@
   void parseAccessSpecifier();
   bool parseEnum();
   bool parseStructLike();
-  void parseConcept();
   bool parseRequires();
   void parseRequiresClause(FormatToken *RequiresToken);
   void parseRequiresExpression(FormatToken *RequiresToken);
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
@@ -1818,9 +1818,6 @@
         break;
       }
       break;
-    case tok::kw_concept:
-      parseConcept();
-      return;
     case tok::kw_requires: {
       if (Style.isCpp()) {
         bool ParsedClause = parseRequires();
@@ -3277,26 +3274,6 @@
   }
 }
 
-/// \brief Parses a concept definition.
-/// \pre The current token has to be the concept keyword.
-///
-/// Returns if either the concept has been completely parsed, or if it detects
-/// that the concept definition is incorrect.
-void UnwrappedLineParser::parseConcept() {
-  assert(FormatTok->is(tok::kw_concept) && "'concept' expected");
-  nextToken();
-  if (!FormatTok->is(tok::identifier))
-    return;
-  nextToken();
-  if (!FormatTok->is(tok::equal))
-    return;
-  nextToken();
-  parseConstraintExpression();
-  if (FormatTok->is(tok::semi))
-    nextToken();
-  addUnwrappedLine();
-}
-
 /// \brief Parses a requires, decides if it is a clause or an expression.
 /// \pre The current token has to be the requires keyword.
 /// \returns true if it parsed a clause.
@@ -3463,6 +3440,8 @@
                                       ? TT_RequiresClauseInARequiresExpression
                                       : TT_RequiresClause);
 
+  // NOTE: parseConstraintExpression is only ever called from this function.
+  // It could be inlined into here.
   parseConstraintExpression();
 
   if (!InRequiresExpression)
@@ -3496,9 +3475,8 @@
 
 /// \brief Parses a constraint expression.
 ///
-/// This is either the definition of a concept, or the body of a requires
-/// clause. It returns, when the parsing is complete, or the expression is
-/// incorrect.
+/// This is the body of a requires clause. It returns, when the parsing is
+/// complete, or the expression is incorrect.
 void UnwrappedLineParser::parseConstraintExpression() {
   // The special handling for lambdas is needed since tryToParseLambda() eats a
   // token and if a requires expression is the last part of a requires clause
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
@@ -23588,10 +23588,10 @@
                "concept DelayedCheck = !!false || requires(T t) { t.bar(); } "
                "&& sizeof(T) <= 8;");
 
-  verifyFormat(
-      "template <typename T>\n"
-      "concept DelayedCheck = static_cast<bool>(0) ||\n"
-      "                       requires(T t) { t.bar(); } && sizeof(T) <= 8;");
+  verifyFormat("template <typename T>\n"
+               "concept DelayedCheck =\n"
+               "    static_cast<bool>(0) || requires(T t) { t.bar(); } && "
+               "sizeof(T) <= 8;");
 
   verifyFormat("template <typename T>\n"
                "concept DelayedCheck = bool(0) || requires(T t) { t.bar(); } "
@@ -23599,8 +23599,8 @@
 
   verifyFormat(
       "template <typename T>\n"
-      "concept DelayedCheck = (bool)(0) ||\n"
-      "                       requires(T t) { t.bar(); } && sizeof(T) <= 8;");
+      "concept DelayedCheck =\n"
+      "    (bool)(0) || requires(T t) { t.bar(); } && sizeof(T) <= 8;");
 
   verifyFormat("template <typename T>\n"
                "concept DelayedCheck = (bool)0 || requires(T t) { t.bar(); } "
@@ -23636,6 +23636,9 @@
   verifyFormat("template <typename T>\n"
                "concept True = S<T>::Value;");
 
+  verifyFormat("template <S T>\n"
+               "concept True = T.field;");
+
   verifyFormat(
       "template <typename T>\n"
       "concept C = []() { return true; }() && requires(T t) { t.bar(); } &&\n"
@@ -23914,11 +23917,9 @@
   verifyFormat("template <typename T> concept True = true;", Style);
 
   verifyFormat(
-      "template <typename T> concept C = decltype([]() -> std::true_type {\n"
-      "                                    return {};\n"
-      "                                  }())::value &&\n"
-      "                                  requires(T t) { t.bar(); } && "
-      "sizeof(T) <= 8;",
+      "template <typename T> concept C =\n"
+      "    decltype([]() -> std::true_type { return {}; }())::value &&\n"
+      "    requires(T t) { t.bar(); } && sizeof(T) <= 8;",
       Style);
 
   verifyFormat("template <typename T> concept Semiregular =\n"
@@ -23936,21 +23937,20 @@
 
   // The following tests are invalid C++, we just want to make sure we don't
   // assert.
-  verifyFormat("template <typename T>\n"
-               "concept C = requires C2<T>;");
+  verifyNoCrash("template <typename T>\n"
+                "concept C = requires C2<T>;");
 
-  verifyFormat("template <typename T>\n"
-               "concept C = 5 + 4;");
+  verifyNoCrash("template <typename T>\n"
+                "concept C = 5 + 4;");
 
-  verifyFormat("template <typename T>\n"
-               "concept C =\n"
-               "class X;");
+  verifyNoCrash("template <typename T>\n"
+                "concept C = class X;");
 
-  verifyFormat("template <typename T>\n"
-               "concept C = [] && true;");
+  verifyNoCrash("template <typename T>\n"
+                "concept C = [] && true;");
 
-  verifyFormat("template <typename T>\n"
-               "concept C = [] && requires(T t) { typename T::size_type; };");
+  verifyNoCrash("template <typename T>\n"
+                "concept C = [] && requires(T t) { typename T::size_type; };");
 }
 
 TEST_F(FormatTest, RequiresClausesPositions) {