[clang] 79210fe - [clang-format] Fix a crash on formatting missing r_paren/r_brace (#138230)

[via cfe-commits]

Author: Owen Pan
Date: 2025-05-02T19:20:42-07:00
New Revision: 79210feb2993ff9a79ef11f8a7016a527d4fcf22

URL: https://github.com/llvm/llvm-project/commit/79210feb2993ff9a79ef11f8a7016a527d4fcf22
DIFF: https://github.com/llvm/llvm-project/commit/79210feb2993ff9a79ef11f8a7016a527d4fcf22.diff

LOG: [clang-format] Fix a crash on formatting missing r_paren/r_brace (#138230)

Fix #138097

Added: 
    

Modified: 
    clang/lib/Format/UnwrappedLineParser.cpp
    clang/unittests/Format/FormatTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index b67634c7f8ee0..ae33f4f6987ca 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -1834,8 +1834,8 @@ void UnwrappedLineParser::parseStructuralElement(
       nextToken();
       if (FormatTok->is(tok::l_paren)) {
         parseParens();
-        assert(FormatTok->Previous);
-        if (FormatTok->Previous->endsSequence(tok::r_paren, tok::kw_auto,
+        if (FormatTok->Previous &&
+            FormatTok->Previous->endsSequence(tok::r_paren, tok::kw_auto,
                                               tok::l_paren)) {
           Line->SeenDecltypeAuto = true;
         }

diff  --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 049df57ab5725..f85e078696730 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -14259,6 +14259,8 @@ TEST_F(FormatTest, IncorrectCodeUnbalancedBraces) {
   verifyNoCrash("struct Foo {\n"
                 "  operator foo(bar\n"
                 "};");
+  verifyNoCrash("decltype( {\n"
+                "  {");
 }
 
 TEST_F(FormatTest, IncorrectUnbalancedBracesInMacrosWithUnicode) {