diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index cf17566..3d6d59a 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -269,6 +269,13 @@
          T->isRecordType()))
       return;
 
+    // The C standard is actually really unclear on this point, and
+    // DR106 tells us what the result should be but not why.  It's
+    // generally best to say that void just doesn't undergo
+    // lvalue-to-rvalue at all.
+    if (T->isVoidType())
+      return;
+
     // C++ [conv.lval]p1:
     //   [...] If T is a non-class type, the type of the prvalue is the
     //   cv-unqualified version of T. Otherwise, the type of the
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index fc396b9..eec2fc8 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -3549,8 +3549,9 @@
   }
 
   DefaultFunctionArrayLvalueConversion(E);
-  RequireCompleteType(E->getExprLoc(), E->getType(),
-                      diag::err_incomplete_type);
+  if (!E->getType()->isVoidType())
+    RequireCompleteType(E->getExprLoc(), E->getType(),
+                        diag::err_incomplete_type);
 }
 
 ExprResult Sema::ActOnFinishFullExpr(Expr *FullExpr) {