[clang-format] [PR46159] Linux kernel 'C' code uses 'try' as a variable name, allow clang-format to handle such cases

Reviewed By: curdeius

Differential Revision: https://reviews.llvm.org/D80940

clang/lib/Format/FormatTokenLexer.cpp

@@ -76,6 +76,8 @@ void FormatTokenLexer::tryMergePreviousTokens() {
     return;
   if (tryMergeForEach())
     return;
+  if (Style.isCpp() && tryTransformTryUsageForC())
+    return;
 
   if (Style.isCSharp()) {
     if (tryMergeCSharpKeywordVariables())
@@ -383,6 +385,26 @@ bool FormatTokenLexer::tryMergeForEach() {
   return true;
 }
 
+bool FormatTokenLexer::tryTransformTryUsageForC() {
+  if (Tokens.size() < 2)
+    return false;
+  auto &Try = *(Tokens.end() - 2);
+  if (!Try->is(tok::kw_try))
+    return false;
+  auto &Next = *(Tokens.end() - 1);
+  if (Next->isOneOf(tok::l_brace, tok::colon))
+    return false;
+
+  if (Tokens.size() > 2) {
+    auto &At = *(Tokens.end() - 3);
+    if (At->is(tok::at))
+      return false;
+  }
+
+  Try->Tok.setKind(tok::identifier);
+  return true;
+}
+
 bool FormatTokenLexer::tryMergeLessLess() {
   // Merge X,less,less,Y into X,lessless,Y unless X or Y is less.
   if (Tokens.size() < 3)

clang/lib/Format/FormatTokenLexer.h

@@ -56,6 +56,7 @@ private:
   bool tryMergeCSharpNullConditional();
   bool tryTransformCSharpForEach();
   bool tryMergeForEach();
+  bool tryTransformTryUsageForC();
 
   bool tryMergeTokens(ArrayRef<tok::TokenKind> Kinds, TokenType NewType);
 

clang/unittests/Format/FormatTest.cpp

@@ -2664,6 +2664,18 @@ TEST_F(FormatTest, FormatTryCatch) {
   verifyIncompleteFormat("try {} catch (");
 }
 
+TEST_F(FormatTest, FormatTryAsAVariable) {
+  verifyFormat("int try;");
+  verifyFormat("int try, size;");
+  verifyFormat("try = foo();");
+  verifyFormat("if (try < size) {\n  return true;\n}");
+
+  verifyFormat("int catch;");
+  verifyFormat("int catch, size;");
+  verifyFormat("catch = foo();");
+  verifyFormat("if (catch < size) {\n  return true;\n}");
+}
+
 TEST_F(FormatTest, FormatSEHTryCatch) {
   verifyFormat("__try {\n"
                "  int a = b * c;\n"