Add better comments to ::new parsing. Thanks to Doug for the review.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@60423 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseExpr.cpp b/lib/Parse/ParseExpr.cpp
index 50b3a7a..52caffb 100644
--- a/lib/Parse/ParseExpr.cpp
+++ b/lib/Parse/ParseExpr.cpp
@@ -639,6 +639,8 @@
     return ParsePostfixExpressionSuffix(Res);
 
   case tok::coloncolon: // [C++] new-expression or [C++] delete-expression
+    // If the next token is neither 'new' nor 'delete', the :: would have been
+    // parsed as a scope specifier already.
     if (NextToken().is(tok::kw_new))
       return ParseCXXNewExpression();
     else
diff --git a/lib/Parse/ParseExprCXX.cpp b/lib/Parse/ParseExprCXX.cpp
index 5d790fa..c126b43 100644
--- a/lib/Parse/ParseExprCXX.cpp
+++ b/lib/Parse/ParseExprCXX.cpp
@@ -38,8 +38,8 @@
       (Tok.isNot(tok::identifier) || NextToken().isNot(tok::coloncolon)))
     return false;
 
-  // Don't parse ::new and ::delete as scope specifiers. It would only make
-  // things a lot more complicated.
+  // ::new and ::delete aren'T nested-name-specifiers, so parsing the :: as
+  // a scope specifier only makes things more complicated.
   if (Tok.is(tok::coloncolon) && (NextToken().is(tok::kw_new) ||
                                   NextToken().is(tok::kw_delete)))
     return false;