[clang-format] Treat lambda in braced init as inline

Fix #125430

Author: owenca

clang/lib/Format/TokenAnnotator.cpp

@@ -5569,7 +5569,8 @@ static bool isAllmanBrace(const FormatToken &Tok) {
 // Returns 'true' if 'Tok' is a function argument.
 static bool IsFunctionArgument(const FormatToken &Tok) {
   return Tok.MatchingParen && Tok.MatchingParen->Next &&
-         Tok.MatchingParen->Next->isOneOf(tok::comma, tok::r_paren);
+         Tok.MatchingParen->Next->isOneOf(tok::comma, tok::r_paren,
+                                          tok::r_brace);
 }
 
 static bool

clang/unittests/Format/FormatTest.cpp

@@ -23712,6 +23712,7 @@ TEST_F(FormatTest, FormatsLambdas) {
   verifyFormat("function([]() { return b; })", MergeInline);
   verifyFormat("function([]() { return b; }, a)", MergeInline);
   verifyFormat("function(a, []() { return b; })", MergeInline);
+  verifyFormat("auto guard = foo{[&] { exit_status = true; }};", MergeInline);
 
   // Check option "BraceWrapping.BeforeLambdaBody" and different state of
   // AllowShortLambdasOnASingleLine