Unlike in C++03, a constant-expression is not an unevaluated operand in C++11.
Split out a new ExpressionEvaluationContext flag for this case, and don't treat
it as unevaluated in C++11. This fixes some crash-on-invalids where we would
allow references to class members in potentially-evaluated constant expressions
in static member functions, and also fixes half of PR10177.

The fix to PR10177 exposed a case where template instantiation failed to provide
a source location for a diagnostic, so TreeTransform has been tweaked to supply
source locations when transforming a type. The source location is still not very
good, but MarkDeclarationsReferencedInType would need to operate on a TypeLoc to
improve it further.

Also fix MarkDeclarationReferenced in C++98 mode to trigger instantiation for
static data members of class templates which are used in constant expressions.
This fixes a link-time problem, but we still incorrectly treat the member as
non-constant. The rest of the fix for that issue is blocked on PCH support for
early-instantiated static data members, which will be added in a subsequent
patch.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@146955 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaExprMember.cpp b/lib/Sema/SemaExprMember.cpp
index 03b1731..65e4449 100644
--- a/lib/Sema/SemaExprMember.cpp
+++ b/lib/Sema/SemaExprMember.cpp
@@ -140,7 +140,7 @@
         return IMA_Mixed_StaticContext;
         
     if (SemaRef.getLangOptions().CPlusPlus0x && hasField) {
-      // C++0x [expr.prim.general]p10:
+      // C++11 [expr.prim.general]p12:
       //   An id-expression that denotes a non-static data member or non-static
       //   member function of a class can only be used:
       //   (...)