[clang-format] Add comment justification for https://reviews.llvm.org/D100778

[penagos]

Please ignore this revision.

[penagos]

Closing old review request.

clang/lib/Format/TokenAnnotator.cpp

bool parseAngle() {
 
     if (Style.Language == FormatStyle::LK_Java &&
         CurrentToken->is(tok::question))
       next();
 
     while (CurrentToken) {
       if (CurrentToken->is(tok::greater)) {
         // Try to do a better job at looking for ">>" within the condition of
-        // a statement.
+        // a statement. Conservatively insert spaces between consecutive ">"
+        // tokens to prevent splitting right bitshift operators and potentially
+        // altering program semantics. This check is overly conservative and
+        // will prevent spaces from being inserted in select nested template
+        // parameter cases, but should not alter program semantics.
         if (CurrentToken->Next && CurrentToken->Next->is(tok::greater) &&
             Left->ParentBracket != tok::less &&
             (isKeywordWithCondition(*Line.First) ||
              CurrentToken->getStartOfNonWhitespace() ==
                  CurrentToken->Next->getStartOfNonWhitespace().getLocWithOffset(
                      -1)))
           return false;
         Left->MatchingParen = CurrentToken;