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
@@ -2180,7 +2180,8 @@
       parseBracedList();
       break;
     case tok::less:
-      if (Style.Language == FormatStyle::LK_Proto) {
+      if (Style.Language == FormatStyle::LK_Proto ||
+          ClosingBraceKind == tok::greater) {
         nextToken();
         parseBracedList(/*ContinueOnSemicolons=*/false, /*IsEnum=*/false,
                         /*ClosingBraceKind=*/tok::greater);
@@ -3220,6 +3221,7 @@
       if (!FormatTok->is(tok::less))
         return;
 
+      nextToken();
       parseBracedList(/*ContinueOnSemicolons=*/false, /*IsEnum=*/false,
                       /*ClosingBraceKind=*/tok::greater);
       break;
@@ -3260,9 +3262,11 @@
 
       // Read identifier with optional template declaration.
       nextToken();
-      if (FormatTok->is(tok::less))
+      if (FormatTok->is(tok::less)) {
+        nextToken();
         parseBracedList(/*ContinueOnSemicolons=*/false, /*IsEnum=*/false,
                         /*ClosingBraceKind=*/tok::greater);
+      }
       break;
     }
   } while (!eof());
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
@@ -24114,6 +24114,12 @@
   verifyFormat("template <class T, class T2>\n"
                "concept Same = __is_same_as<T, T2>;");
 
+  verifyFormat(
+      "template <class _InIt, class _OutIt>\n"
+      "concept _Can_reread_dest =\n"
+      "    std::forward_iterator<_OutIt> &&\n"
+      "    std::same_as<std::iter_value_t<_InIt>, std::iter_value_t<_OutIt>>;");
+
   auto Style = getLLVMStyle();
   Style.BreakBeforeConceptDeclarations = FormatStyle::BBCDS_Allowed;
 
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
@@ -390,6 +390,18 @@
   EXPECT_TOKEN(Tokens[21], tok::r_brace, TT_Unknown);
   EXPECT_EQ(Tokens[21]->MatchingParen, Tokens[15]);
   EXPECT_TRUE(Tokens[21]->ClosesRequiresClause);
+
+  Tokens =
+      annotate("template <class A, class B> concept C ="
+               "std::same_as<std::iter_value_t<A>, std::iter_value_t<B>>;");
+  ASSERT_EQ(Tokens.size(), 31u) << Tokens;
+  EXPECT_TOKEN(Tokens[8], tok::kw_concept, TT_Unknown);
+  EXPECT_TOKEN(Tokens[14], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[18], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[20], tok::greater, TT_TemplateCloser);
+  EXPECT_TOKEN(Tokens[25], tok::less, TT_TemplateOpener);
+  EXPECT_TOKEN(Tokens[27], tok::greater, TT_TemplateCloser);
+  EXPECT_TOKEN(Tokens[28], tok::greater, TT_TemplateCloser);
 }
 
 TEST_F(TokenAnnotatorTest, UnderstandsRequiresExpressions) {