r363195 - Add comment to r363191 code as requested in code review

[Reid Kleckner via cfe-commits]

Author: rnk
Date: Wed Jun 12 12:50:06 2019
New Revision: 363195

URL: http://llvm.org/viewvc/llvm-project?rev=363195&view=rev
Log:
Add comment to r363191 code as requested in code review

Modified:
    cfe/trunk/lib/AST/ASTContext.cpp

Modified: cfe/trunk/lib/AST/ASTContext.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/AST/ASTContext.cpp?rev=363195&r1=363194&r2=363195&view=diff
==============================================================================
--- cfe/trunk/lib/AST/ASTContext.cpp (original)
+++ cfe/trunk/lib/AST/ASTContext.cpp Wed Jun 12 12:50:06 2019
@@ -9804,8 +9804,11 @@ static GVALinkage basicGVALinkageForVari
       // was marked inline. MSVC 14.21.27702 headers define _Is_integral in a
       // header this way, and we don't want to emit non-discardable definitions
       // of these variables in every TU that includes <type_traits>. This
-      // behavior can be removed if the headers change to explicitly mark such
-      // variable template specializations inline.
+      // behavior is non-conforming, since another TU could use an extern
+      // template declaration for this variable, but for constexpr variables,
+      // it's unlikely for a user to want to do that. This behavior can be
+      // removed if the headers change to explicitly mark such variable template
+      // specializations inline.
       if (isa<VarTemplateSpecializationDecl>(VD) && VD->isConstexpr())
         return GVA_DiscardableODR;