[NFC] Add assertion that we assume a valid macro argument index.
llvm-svn: 314600
diff --git a/clang/lib/Lex/MacroArgs.cpp b/clang/lib/Lex/MacroArgs.cpp
index de54f39..d2525c0 100644
--- a/clang/lib/Lex/MacroArgs.cpp
+++ b/clang/lib/Lex/MacroArgs.cpp
@@ -118,10 +118,13 @@
/// getUnexpArgument - Return the unexpanded tokens for the specified formal.
///
const Token *MacroArgs::getUnexpArgument(unsigned Arg) const {
+
+ assert(Arg < getNumMacroArguments() && "Invalid arg #");
// The unexpanded argument tokens start immediately after the MacroArgs object
// in memory.
const Token *Start = getTrailingObjects<Token>();
const Token *Result = Start;
+
// Scan to find Arg.
for (; Arg; ++Result) {
assert(Result < Start+NumUnexpArgTokens && "Invalid arg #");