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

owenca · IanWood1 · commit a6ce521ea622 · 2025-05-06T08:54:48.000-07:00
Fix llvm#138097
diff --git 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
@@ -14259,6 +14259,8 @@ TEST_F(FormatTest, IncorrectCodeUnbalancedBraces) {
   verifyNoCrash("struct Foo {\n"
                 "  operator foo(bar\n"
                 "};");
+  verifyNoCrash("decltype( {\n"
+                "  {");
 }
 
 TEST_F(FormatTest, IncorrectUnbalancedBracesInMacrosWithUnicode) {

Original file line number	Diff line number	Diff line change
`@@ -14259,6 +14259,8 @@ TEST_F(FormatTest, IncorrectCodeUnbalancedBraces) {`
`14259`	`14259`	`verifyNoCrash("struct Foo {\n"`
`14260`	`14260`	`" operator foo(bar\n"`
`14261`	`14261`	`"};");`
	`14262`	`+ verifyNoCrash("decltype( {\n"`
	`14263`	`+ " {");`
`14262`	`14264`	`}`
`14263`	`14265`
`14264`	`14266`	`TEST_F(FormatTest, IncorrectUnbalancedBracesInMacrosWithUnicode) {`