diff --git a/sprout/array.hpp b/sprout/array.hpp
index 484c18b8..87d498b2 100644
--- a/sprout/array.hpp
+++ b/sprout/array.hpp
@@ -130,12 +130,16 @@ namespace sprout {
 			return elems[i];
 		}
 		reference at(size_type i) {
-			rangecheck(i);
-			return elems[i];
+			return i < size()
+				? elems[i]
+				: (throw std::out_of_range("array<>: index out of range"), elems[i])
+				;
 		}
-		const_reference at(size_type i) const {
-			rangecheck(i);
-			return elems[i];
+		SPROUT_CONSTEXPR const_reference at(size_type i) const {
+			return i < size()
+				? elems[i]
+				: (throw std::out_of_range("array<>: index out of range"), elems[i])
+				;
 		}
 		reference front() {
 			return elems[0];
diff --git a/sprout/pit.hpp b/sprout/pit.hpp
index 447507c5..4a5a4b91 100644
--- a/sprout/pit.hpp
+++ b/sprout/pit.hpp
@@ -98,12 +98,16 @@ namespace sprout {
 			return elem;
 		}
 		reference at(size_type i) {
-			rangecheck(i);
-			return elem;
+			return i < size()
+				? elem
+				: (throw std::out_of_range("pit<>: index out of range"), elem)
+				;
 		}
-		const_reference at(size_type i) const {
-			rangecheck(i);
-			return elem;
+		SPROUT_CONSTEXPR const_reference at(size_type i) const {
+			return i < size()
+				? elem
+				: (throw std::out_of_range("pit<>: index out of range"), elem)
+				;
 		}
 		reference front() {
 			return elem;
diff --git a/sprout/random/unique_seed.hpp b/sprout/random/unique_seed.hpp
index 9c0f2244..b201ab44 100644
--- a/sprout/random/unique_seed.hpp
+++ b/sprout/random/unique_seed.hpp
@@ -1,6 +1,10 @@
 #ifndef SPROUT_RANDOM_UNIQUE_SEED_HPP
 #define SPROUT_RANDOM_UNIQUE_SEED_HPP
 
+#ifndef SPROUT_CONFIG_DISABLE_CONSTEXPR
+#	include <cstddef>
+#	include <type_traits>
+#endif
 #include <sprout/config.hpp>
 #include <sprout/functional/hash/hash.hpp>
 #include <sprout/preprocessor/unique_string.hpp>
@@ -8,7 +12,11 @@
 //
 // SPROUT_UNIQUE_SEED
 //
-#define SPROUT_UNIQUE_SEED (::sprout::hash_value(SPROUT_PP_UNIQUE_STRING))
+#ifndef SPROUT_CONFIG_DISABLE_CONSTEXPR
+#	define SPROUT_UNIQUE_SEED (::std::integral_constant< ::std::size_t, ::sprout::hash_value(SPROUT_PP_UNIQUE_STRING)>::value)
+#else
+#	define SPROUT_UNIQUE_SEED (::sprout::hash_value(SPROUT_PP_UNIQUE_STRING))
+#endif
 
 #endif	// #ifndef SPROUT_RANDOM_UNIQUE_SEED_HPP
 
diff --git a/sprout/string.hpp b/sprout/string.hpp
index 1ba8af92..a3a1c2c5 100644
--- a/sprout/string.hpp
+++ b/sprout/string.hpp
@@ -375,12 +375,16 @@ namespace sprout {
 			return elems[i];
 		}
 		reference at(size_type i) {
-			rangecheck(i);
-			return elems[i];
+			return i < size()
+				? elems[i]
+				: (throw std::out_of_range("basic_string<>: index out of range"), elems[i])
+				;
 		}
-		const_reference at(size_type i) const {
-			rangecheck(i);
-			return elems[i];
+		SPROUT_CONSTEXPR const_reference at(size_type i) const {
+			return i < size()
+				? elems[i]
+				: (throw std::out_of_range("basic_string<>: index out of range"), elems[i])
+				;
 		}
 		reference front() {
 			return elems[0];
diff --git a/sprout/sub_array.hpp b/sprout/sub_array.hpp
index d8c2a381..97153f71 100644
--- a/sprout/sub_array.hpp
+++ b/sprout/sub_array.hpp
@@ -310,12 +310,16 @@ namespace sprout {
 			return *sprout::next(sprout::begin(get_array()), first_ + i);
 		}
 		reference at(size_type i) {
-			rangecheck(i);
-			return *sprout::next(sprout::begin(get_array()), first_ + i);
+			return i < size()
+				? *sprout::next(sprout::begin(get_array()), first_ + i)
+				: (throw std::out_of_range("sub_array<>: index out of range"), *sprout::next(sprout::begin(get_array()), first_ + i))
+				;
 		}
-		const_reference at(size_type i) const {
-			rangecheck(i);
-			return *sprout::next(sprout::begin(get_array()), first_ + i);
+		SPROUT_CONSTEXPR const_reference at(size_type i) const {
+			return i < size()
+				? *sprout::next(sprout::begin(get_array()), first_ + i)
+				: (throw std::out_of_range("sub_array<>: index out of range"), *sprout::next(sprout::begin(get_array()), first_ + i))
+				;
 		}
 		reference front() {
 			return *sprout::next(sprout::begin(get_array()), first_);
diff --git a/sprout/uuid/uuid.hpp b/sprout/uuid/uuid.hpp
index b0492af2..3ce6a8c6 100644
--- a/sprout/uuid/uuid.hpp
+++ b/sprout/uuid/uuid.hpp
@@ -157,12 +157,16 @@ namespace sprout {
 				return elems[i];
 			}
 			reference at(size_type i) {
-				rangecheck(i);
-				return elems[i];
+				return i < size()
+					? elems[i]
+					: (throw std::out_of_range("uuid: index out of range"), elems[i])
+					;
 			}
-			const_reference at(size_type i) const {
-				rangecheck(i);
-				return elems[i];
+			SPROUT_CONSTEXPR const_reference at(size_type i) const {
+				return i < size()
+					? elems[i]
+					: (throw std::out_of_range("uuid: index out of range"), elems[i])
+					;
 			}
 			reference front() {
 				return elems[0];
@@ -193,7 +197,7 @@ namespace sprout {
 			}
 			void rangecheck(size_type i) const {
 				if (i >= size()) {
-					throw std::out_of_range("uuid<>: index out of range");
+					throw std::out_of_range("uuid: index out of range");
 				}
 			}