[ADT] Move to_vector from STLExtras.h to SmallVector.h

Nothing breaks, so this probably has zero impact, but it seems nice,
since to_vector is more like makeArrayRef, and should really live in
SmallVector.h.

include/llvm/ADT/STLExtras.h

@@ -17,7 +17,6 @@
 #define LLVM_ADT_STLEXTRAS_H
 
 #include "llvm/ADT/Optional.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Config/abi-breaking.h"
@@ -51,10 +50,6 @@ namespace detail {
 template <typename RangeT>
 using IterOfRange = decltype(std::begin(std::declval<RangeT &>()));
 
-template <typename RangeT>
-using ValueOfRange = typename std::remove_reference<decltype(
-    *std::begin(std::declval<RangeT &>()))>::type;
-
 } // end namespace detail
 
 //===----------------------------------------------------------------------===//
@@ -1334,15 +1329,6 @@ bool is_splat(R &&Range) {
          std::equal(adl_begin(Range) + 1, adl_end(Range), adl_begin(Range)));
 }
 
-/// Given a range of type R, iterate the entire range and return a
-/// SmallVector with elements of the vector.  This is useful, for example,
-/// when you want to iterate a range and then sort the results.
-template <unsigned Size, typename R>
-SmallVector<typename std::remove_const<detail::ValueOfRange<R>>::type, Size>
-to_vector(R &&Range) {
-  return {adl_begin(Range), adl_end(Range)};
-}
-
 /// Provide a container algorithm similar to C++ Library Fundamentals v2's
 /// `erase_if` which is equivalent to:
 ///

include/llvm/ADT/SmallVector.h

@@ -907,6 +907,17 @@ inline size_t capacity_in_bytes(const SmallVector<T, N> &X) {
   return X.capacity_in_bytes();
 }
 
+/// Given a range of type R, iterate the entire range and return a
+/// SmallVector with elements of the vector.  This is useful, for example,
+/// when you want to iterate a range and then sort the results.
+template <unsigned Size, typename R>
+SmallVector<typename std::remove_const<typename std::remove_reference<
+                decltype(*std::begin(std::declval<R &>()))>::type>::type,
+            Size>
+to_vector(R &&Range) {
+  return {std::begin(Range), std::end(Range)};
+}
+
 } // end namespace llvm
 
 namespace std {