[PATCH] D34405: [Testing/Support] Remove the const_cast in TakeExpected

[Pavel Labath via Phabricator via llvm-commits]

labath created this revision.

The const_cast in the "const" version of TakeExpected was quite
dangerous, as the function does indeed modify the apparently const
argument.

I assume the reason the const overload was added was to make the
function bind to xvalues(temporaries). That can be also achieved with
rvalue references, so I use that instead.

Using the ASSERT macros on const Expected objects will now become
illegal, but I believe that is correct, as it is not actually possible
to inspect the error stored in an Expected object without modifying it.


https://reviews.llvm.org/D34405

Files:
  include/llvm/Testing/Support/Error.h


Index: include/llvm/Testing/Support/Error.h
===================================================================
--- include/llvm/Testing/Support/Error.h
+++ include/llvm/Testing/Support/Error.h
@@ -30,8 +30,8 @@
   return Result;
 }
 
-template <typename T> ExpectedHolder<T> TakeExpected(const Expected<T> &Exp) {
-  return TakeExpected(const_cast<Expected<T> &>(Exp));
+template <typename T> ExpectedHolder<T> TakeExpected(Expected<T> &&Exp) {
+  return TakeExpected(Exp);
 }
 } // namespace detail
 


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