diff --git a/.clang-tidy b/.clang-tidy
index 10ac924..d28fb6c 100644
--- a/.clang-tidy
+++ b/.clang-tidy
@@ -1,202 +1,202 @@
 ---
 Checks: # enabled
   - 'bugprone-*,
-  cert-*,
-  clang-analyzer-*,
-  concurrency-*,
-  cppcoreguidelines-*,
-  hicpp-*,
-  misc-*,
-  modernize-*,
-  performance-*,
-  portability-*,
-  readability-*,'
+    cert-*,
+    clang-analyzer-*,
+    concurrency-*,
+    cppcoreguidelines-*,
+    hicpp-*,
+    misc-*,
+    modernize-*,
+    performance-*,
+    portability-*,
+    readability-*,'
   # disabled useless checks
   - '-*-logical-op-parentheses,
-  -*-dangling-else,
-  -*-use-trailing-return-type,
-  -*-braces-around-statements,
-  -*-misleading-indentation,
-  -*-macro-usage,
-  -*-non-private-member-variables-in-classes,
-  -*-macro-parentheses,
-  -*-forwarding-reference-overload,
-  -*-pro-type-union-access,
-  -*-identifier-length,
-  -*-explicit-conversions,
-  -*-unconventional-assign-operator,
-  -*-uppercase-literal-suffix,
-  -*-qualified-auto,
-  -*-pro-bounds-constant-array-index,
-  -*-exception-escape,
-  -*-const-or-ref-data-members,
-  -cert-dcl21-cpp,
-  -*-missing-std-forward,
-  -*-rvalue-reference-param-not-moved,
-  -*-include-cleaner,
-  -*-swappable-parameters,
-  -*-reserved-identifier'
+    -*-dangling-else,
+    -*-use-trailing-return-type,
+    -*-braces-around-statements,
+    -*-misleading-indentation,
+    -*-macro-usage,
+    -*-non-private-member-variables-in-classes,
+    -*-macro-parentheses,
+    -*-forwarding-reference-overload,
+    -*-pro-type-union-access,
+    -*-identifier-length,
+    -*-explicit-conversions,
+    -*-unconventional-assign-operator,
+    -*-uppercase-literal-suffix,
+    -*-qualified-auto,
+    -*-pro-bounds-constant-array-index,
+    -*-exception-escape,
+    -*-const-or-ref-data-members,
+    -cert-dcl21-cpp,
+    -*-missing-std-forward,
+    -*-rvalue-reference-param-not-moved,
+    -*-include-cleaner,
+    -*-swappable-parameters,
+    -*-reserved-identifier'
   # disabled alias
   - '-bugprone-narrowing-conversions,
-  -cert-con36-c,
-  -cert-con54-cpp,
-  -cert-dcl03-c,
-  -cert-dcl16-c,
-  -cert-dcl37-c,
-  -cert-dcl51-cpp,
-  -cert-dcl54-cpp,
-  -cert-dcl59-cpp,
-  -cert-err09-cpp,
-  -cert-err61-cpp,
-  -cert-exp42-c,
-  -cert-fio38-c,
-  -cert-flp37-c,
-  -cert-msc24-c,
-  -cert-msc30-c,
-  -cert-msc32-c,
-  -cert-msc33-c,
-  -cert-msc54-cpp,
-  -cert-oop11-cpp,
-  -cert-oop54-cpp,
-  -cert-pos44-c,
-  -cert-pos47-c,
-  -cert-sig30-c,
-  -cert-str34-c,
-  -clang-analyzer-core.BitwiseShift,
-  -clang-analyzer-core.CallAndMessage,
-  -clang-analyzer-core.DivideZero,
-  -clang-analyzer-core.NonNullParamChecker,
-  -clang-analyzer-core.NullDereference,
-  -clang-analyzer-core.StackAddressEscape,
-  -clang-analyzer-core.UndefinedBinaryOperatorResult,
-  -clang-analyzer-core.VLASize,
-  -clang-analyzer-core.uninitialized.ArraySubscript,
-  -clang-analyzer-core.uninitialized.Assign,
-  -clang-analyzer-core.uninitialized.Branch,
-  -clang-analyzer-core.uninitialized.CapturedBlockVariable,
-  -clang-analyzer-core.uninitialized.NewArraySize,
-  -clang-analyzer-core.uninitialized.UndefReturn,
-  -clang-analyzer-cplusplus.InnerPointer,
-  -clang-analyzer-cplusplus.Move,
-  -clang-analyzer-cplusplus.NewDelete,
-  -clang-analyzer-cplusplus.NewDeleteLeaks,
-  -clang-analyzer-cplusplus.PlacementNew,
-  -clang-analyzer-cplusplus.PureVirtualCall,
-  -clang-analyzer-cplusplus.StringChecker,
-  -clang-analyzer-deadcode.DeadStores,
-  -clang-analyzer-fuchsia.HandleChecker,
-  -clang-analyzer-nullability.NullPassedToNonnull,
-  -clang-analyzer-nullability.NullReturnedFromNonnull,
-  -clang-analyzer-nullability.NullableDereferenced,
-  -clang-analyzer-nullability.NullablePassedToNonnull,
-  -clang-analyzer-nullability.NullableReturnedFromNonnull,
-  -clang-analyzer-optin.cplusplus.UninitializedObject,
-  -clang-analyzer-optin.cplusplus.VirtualCall,
-  -clang-analyzer-optin.mpi.MPI-Checker,
-  -clang-analyzer-optin.osx.OSObjectCStyleCast,
-  -clang-analyzer-optin.osx.cocoa.localizability.EmptyLocalizationContextChecker,
-  -clang-analyzer-optin.osx.cocoa.localizability.NonLocalizedStringChecker,
-  -clang-analyzer-optin.performance.GCDAntipattern,
-  -clang-analyzer-optin.performance.Padding,
-  -clang-analyzer-optin.portability.UnixAPI,
-  -clang-analyzer-osx.API,
-  -clang-analyzer-osx.MIG,
-  -clang-analyzer-osx.NumberObjectConversion,
-  -clang-analyzer-osx.OSObjectRetainCount,
-  -clang-analyzer-osx.ObjCProperty,
-  -clang-analyzer-osx.SecKeychainAPI,
-  -clang-analyzer-osx.cocoa.AtSync,
-  -clang-analyzer-osx.cocoa.AutoreleaseWrite,
-  -clang-analyzer-osx.cocoa.ClassRelease,
-  -clang-analyzer-osx.cocoa.Dealloc,
-  -clang-analyzer-osx.cocoa.IncompatibleMethodTypes,
-  -clang-analyzer-osx.cocoa.Loops,
-  -clang-analyzer-osx.cocoa.MissingSuperCall,
-  -clang-analyzer-osx.cocoa.NSAutoreleasePool,
-  -clang-analyzer-osx.cocoa.NSError,
-  -clang-analyzer-osx.cocoa.NilArg,
-  -clang-analyzer-osx.cocoa.NonNilReturnValue,
-  -clang-analyzer-osx.cocoa.ObjCGenerics,
-  -clang-analyzer-osx.cocoa.RetainCount,
-  -clang-analyzer-osx.cocoa.RunLoopAutoreleaseLeak,
-  -clang-analyzer-osx.cocoa.SelfInit,
-  -clang-analyzer-osx.cocoa.SuperDealloc,
-  -clang-analyzer-osx.cocoa.UnusedIvars,
-  -clang-analyzer-osx.cocoa.VariadicMethodTypes,
-  -clang-analyzer-osx.coreFoundation.CFError,
-  -clang-analyzer-osx.coreFoundation.CFNumber,
-  -clang-analyzer-osx.coreFoundation.CFRetainRelease,
-  -clang-analyzer-osx.coreFoundation.containers.OutOfBounds,
-  -clang-analyzer-osx.coreFoundation.containers.PointerSizedValues,
-  -clang-analyzer-security.FloatLoopCounter,
-  -clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling,
-  -clang-analyzer-security.insecureAPI.UncheckedReturn,
-  -clang-analyzer-security.insecureAPI.bcmp,
-  -clang-analyzer-security.insecureAPI.bcopy,
-  -clang-analyzer-security.insecureAPI.bzero,
-  -clang-analyzer-security.insecureAPI.decodeValueOfObjCType,
-  -clang-analyzer-security.insecureAPI.getpw,
-  -clang-analyzer-security.insecureAPI.gets,
-  -clang-analyzer-security.insecureAPI.mkstemp,
-  -clang-analyzer-security.insecureAPI.mktemp,
-  -clang-analyzer-security.insecureAPI.rand,
-  -clang-analyzer-security.insecureAPI.strcpy,
-  -clang-analyzer-security.insecureAPI.vfork,
-  -clang-analyzer-unix.API,
-  -clang-analyzer-unix.Malloc,
-  -clang-analyzer-unix.MallocSizeof,
-  -clang-analyzer-unix.MismatchedDeallocator,
-  -clang-analyzer-unix.Vfork,
-  -clang-analyzer-unix.cstring.BadSizeArg,
-  -clang-analyzer-unix.cstring.NullArg,
-  -clang-analyzer-valist.CopyToSelf,
-  -clang-analyzer-valist.Uninitialized,
-  -clang-analyzer-valist.Unterminated,
-  -clang-analyzer-webkit.NoUncountedMemberChecker,
-  -clang-analyzer-webkit.RefCntblBaseVirtualDtor,
-  -clang-analyzer-webkit.UncountedLambdaCapturesChecker,
-  -cppcoreguidelines-avoid-c-arrays,
-  -cppcoreguidelines-avoid-magic-numbers,
-  -cppcoreguidelines-c-copy-assignment-signature,
-  -cppcoreguidelines-explicit-virtual-functions,
-  -cppcoreguidelines-macro-to-enum,
-  -cppcoreguidelines-noexcept-destructor,
-  -cppcoreguidelines-noexcept-move-operations,
-  -cppcoreguidelines-noexcept-swap,
-  -cppcoreguidelines-non-private-member-variables-in-classes,
-  -cppcoreguidelines-use-default-member-init,
-  -fuchsia-header-anon-namespaces,
-  -google-readability-braces-around-statements,
-  -google-readability-function-size,
-  -google-readability-namespace-comments,
-  -hicpp-avoid-c-arrays,
-  -hicpp-avoid-goto,
-  -hicpp-braces-around-statements,
-  -hicpp-deprecated-headers,
-  -hicpp-explicit-conversions,
-  -hicpp-function-size,
-  -hicpp-invalid-access-moved,
-  -hicpp-member-init,
-  -hicpp-move-const-arg,
-  -hicpp-named-parameter,
-  -hicpp-new-delete-operators,
-  -hicpp-no-array-decay,
-  -hicpp-no-malloc,
-  -hicpp-noexcept-move,
-  -hicpp-special-member-functions,
-  -hicpp-static-assert,
-  -hicpp-undelegated-constructor,
-  -hicpp-uppercase-literal-suffix,
-  -hicpp-use-auto,
-  -hicpp-use-emplace,
-  -hicpp-use-equals-default,
-  -hicpp-use-equals-delete,
-  -hicpp-use-noexcept,
-  -hicpp-use-nullptr,
-  -hicpp-use-override,
-  -hicpp-vararg,
-  -llvm-else-after-return,
-  -llvm-qualified-auto'
+    -cert-con36-c,
+    -cert-con54-cpp,
+    -cert-dcl03-c,
+    -cert-dcl16-c,
+    -cert-dcl37-c,
+    -cert-dcl51-cpp,
+    -cert-dcl54-cpp,
+    -cert-dcl59-cpp,
+    -cert-err09-cpp,
+    -cert-err61-cpp,
+    -cert-exp42-c,
+    -cert-fio38-c,
+    -cert-flp37-c,
+    -cert-msc24-c,
+    -cert-msc30-c,
+    -cert-msc32-c,
+    -cert-msc33-c,
+    -cert-msc54-cpp,
+    -cert-oop11-cpp,
+    -cert-oop54-cpp,
+    -cert-pos44-c,
+    -cert-pos47-c,
+    -cert-sig30-c,
+    -cert-str34-c,
+    -clang-analyzer-core.BitwiseShift,
+    -clang-analyzer-core.CallAndMessage,
+    -clang-analyzer-core.DivideZero,
+    -clang-analyzer-core.NonNullParamChecker,
+    -clang-analyzer-core.NullDereference,
+    -clang-analyzer-core.StackAddressEscape,
+    -clang-analyzer-core.UndefinedBinaryOperatorResult,
+    -clang-analyzer-core.VLASize,
+    -clang-analyzer-core.uninitialized.ArraySubscript,
+    -clang-analyzer-core.uninitialized.Assign,
+    -clang-analyzer-core.uninitialized.Branch,
+    -clang-analyzer-core.uninitialized.CapturedBlockVariable,
+    -clang-analyzer-core.uninitialized.NewArraySize,
+    -clang-analyzer-core.uninitialized.UndefReturn,
+    -clang-analyzer-cplusplus.InnerPointer,
+    -clang-analyzer-cplusplus.Move,
+    -clang-analyzer-cplusplus.NewDelete,
+    -clang-analyzer-cplusplus.NewDeleteLeaks,
+    -clang-analyzer-cplusplus.PlacementNew,
+    -clang-analyzer-cplusplus.PureVirtualCall,
+    -clang-analyzer-cplusplus.StringChecker,
+    -clang-analyzer-deadcode.DeadStores,
+    -clang-analyzer-fuchsia.HandleChecker,
+    -clang-analyzer-nullability.NullPassedToNonnull,
+    -clang-analyzer-nullability.NullReturnedFromNonnull,
+    -clang-analyzer-nullability.NullableDereferenced,
+    -clang-analyzer-nullability.NullablePassedToNonnull,
+    -clang-analyzer-nullability.NullableReturnedFromNonnull,
+    -clang-analyzer-optin.cplusplus.UninitializedObject,
+    -clang-analyzer-optin.cplusplus.VirtualCall,
+    -clang-analyzer-optin.mpi.MPI-Checker,
+    -clang-analyzer-optin.osx.OSObjectCStyleCast,
+    -clang-analyzer-optin.osx.cocoa.localizability.EmptyLocalizationContextChecker,
+    -clang-analyzer-optin.osx.cocoa.localizability.NonLocalizedStringChecker,
+    -clang-analyzer-optin.performance.GCDAntipattern,
+    -clang-analyzer-optin.performance.Padding,
+    -clang-analyzer-optin.portability.UnixAPI,
+    -clang-analyzer-osx.API,
+    -clang-analyzer-osx.MIG,
+    -clang-analyzer-osx.NumberObjectConversion,
+    -clang-analyzer-osx.OSObjectRetainCount,
+    -clang-analyzer-osx.ObjCProperty,
+    -clang-analyzer-osx.SecKeychainAPI,
+    -clang-analyzer-osx.cocoa.AtSync,
+    -clang-analyzer-osx.cocoa.AutoreleaseWrite,
+    -clang-analyzer-osx.cocoa.ClassRelease,
+    -clang-analyzer-osx.cocoa.Dealloc,
+    -clang-analyzer-osx.cocoa.IncompatibleMethodTypes,
+    -clang-analyzer-osx.cocoa.Loops,
+    -clang-analyzer-osx.cocoa.MissingSuperCall,
+    -clang-analyzer-osx.cocoa.NSAutoreleasePool,
+    -clang-analyzer-osx.cocoa.NSError,
+    -clang-analyzer-osx.cocoa.NilArg,
+    -clang-analyzer-osx.cocoa.NonNilReturnValue,
+    -clang-analyzer-osx.cocoa.ObjCGenerics,
+    -clang-analyzer-osx.cocoa.RetainCount,
+    -clang-analyzer-osx.cocoa.RunLoopAutoreleaseLeak,
+    -clang-analyzer-osx.cocoa.SelfInit,
+    -clang-analyzer-osx.cocoa.SuperDealloc,
+    -clang-analyzer-osx.cocoa.UnusedIvars,
+    -clang-analyzer-osx.cocoa.VariadicMethodTypes,
+    -clang-analyzer-osx.coreFoundation.CFError,
+    -clang-analyzer-osx.coreFoundation.CFNumber,
+    -clang-analyzer-osx.coreFoundation.CFRetainRelease,
+    -clang-analyzer-osx.coreFoundation.containers.OutOfBounds,
+    -clang-analyzer-osx.coreFoundation.containers.PointerSizedValues,
+    -clang-analyzer-security.FloatLoopCounter,
+    -clang-analyzer-security.insecureAPI.DeprecatedOrUnsafeBufferHandling,
+    -clang-analyzer-security.insecureAPI.UncheckedReturn,
+    -clang-analyzer-security.insecureAPI.bcmp,
+    -clang-analyzer-security.insecureAPI.bcopy,
+    -clang-analyzer-security.insecureAPI.bzero,
+    -clang-analyzer-security.insecureAPI.decodeValueOfObjCType,
+    -clang-analyzer-security.insecureAPI.getpw,
+    -clang-analyzer-security.insecureAPI.gets,
+    -clang-analyzer-security.insecureAPI.mkstemp,
+    -clang-analyzer-security.insecureAPI.mktemp,
+    -clang-analyzer-security.insecureAPI.rand,
+    -clang-analyzer-security.insecureAPI.strcpy,
+    -clang-analyzer-security.insecureAPI.vfork,
+    -clang-analyzer-unix.API,
+    -clang-analyzer-unix.Malloc,
+    -clang-analyzer-unix.MallocSizeof,
+    -clang-analyzer-unix.MismatchedDeallocator,
+    -clang-analyzer-unix.Vfork,
+    -clang-analyzer-unix.cstring.BadSizeArg,
+    -clang-analyzer-unix.cstring.NullArg,
+    -clang-analyzer-valist.CopyToSelf,
+    -clang-analyzer-valist.Uninitialized,
+    -clang-analyzer-valist.Unterminated,
+    -clang-analyzer-webkit.NoUncountedMemberChecker,
+    -clang-analyzer-webkit.RefCntblBaseVirtualDtor,
+    -clang-analyzer-webkit.UncountedLambdaCapturesChecker,
+    -cppcoreguidelines-avoid-c-arrays,
+    -cppcoreguidelines-avoid-magic-numbers,
+    -cppcoreguidelines-c-copy-assignment-signature,
+    -cppcoreguidelines-explicit-virtual-functions,
+    -cppcoreguidelines-macro-to-enum,
+    -cppcoreguidelines-noexcept-destructor,
+    -cppcoreguidelines-noexcept-move-operations,
+    -cppcoreguidelines-noexcept-swap,
+    -cppcoreguidelines-non-private-member-variables-in-classes,
+    -cppcoreguidelines-use-default-member-init,
+    -fuchsia-header-anon-namespaces,
+    -google-readability-braces-around-statements,
+    -google-readability-function-size,
+    -google-readability-namespace-comments,
+    -hicpp-avoid-c-arrays,
+    -hicpp-avoid-goto,
+    -hicpp-braces-around-statements,
+    -hicpp-deprecated-headers,
+    -hicpp-explicit-conversions,
+    -hicpp-function-size,
+    -hicpp-invalid-access-moved,
+    -hicpp-member-init,
+    -hicpp-move-const-arg,
+    -hicpp-named-parameter,
+    -hicpp-new-delete-operators,
+    -hicpp-no-array-decay,
+    -hicpp-no-malloc,
+    -hicpp-noexcept-move,
+    -hicpp-special-member-functions,
+    -hicpp-static-assert,
+    -hicpp-undelegated-constructor,
+    -hicpp-uppercase-literal-suffix,
+    -hicpp-use-auto,
+    -hicpp-use-emplace,
+    -hicpp-use-equals-default,
+    -hicpp-use-equals-delete,
+    -hicpp-use-noexcept,
+    -hicpp-use-nullptr,
+    -hicpp-use-override,
+    -hicpp-vararg,
+    -llvm-else-after-return,
+    -llvm-qualified-auto'
 WarningsAsErrors: '*'
 FormatStyle: 'file'
 HeaderFilterRegex: '(include/)|(src/)'
diff --git a/include/stdsharp/concepts/concepts.h b/include/stdsharp/concepts/concepts.h
index 17c36e8..3f508b7 100644
--- a/include/stdsharp/concepts/concepts.h
+++ b/include/stdsharp/concepts/concepts.h
@@ -3,9 +3,11 @@
 //
 #pragma once
 
-#include <compare>
 #include <concepts>
+#include <cstddef>
 #include <type_traits>
+#include <utility>
+#include <tuple>
 
 #include "../macros.h"
 #include "../namespace_alias.h"
@@ -33,6 +35,9 @@ namespace stdsharp
     template<typename T>
     concept const_ = std::is_const_v<T>;
 
+    template<typename T>
+    concept non_const = !const_<T>;
+
     template<typename T>
     concept const_lvalue_ref = std::is_lvalue_reference_v<T> && const_<std::remove_reference_t<T>>;
 
@@ -440,10 +445,7 @@ namespace stdsharp
         copy_assignable<T> && //
         std::equality_comparable<T> && //
         weakly_equality_comparable_with<T, std::nullptr_t>;
-}
 
-namespace stdsharp
-{
     template<typename T>
     concept referenceable = requires(T&) { 0; };
 
diff --git a/include/stdsharp/memory/aligned.h b/include/stdsharp/memory/aligned.h
index 158746d..b432c75 100644
--- a/include/stdsharp/memory/aligned.h
+++ b/include/stdsharp/memory/aligned.h
@@ -6,11 +6,12 @@ namespace stdsharp
 {
     inline constexpr struct align_fn
     {
-        template<typename T, std::size_t Size>
-            requires(!const_<T>)
-        auto
-            operator()(const std::size_t alignment, const std::size_t size, const std::span<T, Size>& span)
-                const noexcept
+        template<non_const T, std::size_t Size>
+        auto operator()(
+            const std::size_t alignment,
+            const std::size_t size,
+            const std::span<T, Size>& span
+        ) const noexcept
         {
             auto space = span.size_bytes();
             void* void_ptr = span.data();
diff --git a/include/stdsharp/synchronizer.h b/include/stdsharp/synchronizer.h
index 48aa8e8..8ba41f9 100644
--- a/include/stdsharp/synchronizer.h
+++ b/include/stdsharp/synchronizer.h
@@ -7,7 +7,8 @@
 
 namespace stdsharp
 {
-    template<typename T, shared_mutex Lockable = std::shared_mutex>
+    template<non_const T, shared_lockable Lockable = std::shared_mutex>
+        requires basic_lockable<Lockable>
     class synchronizer
     {
     public:
@@ -18,7 +19,13 @@ namespace stdsharp
         synchronizer() = default;
 
         template<typename... Args>
-            requires std::constructible_from<value_type, Args...>
+            requires requires {
+                requires std::constructible_from<value_type, Args...>;
+                requires std::default_initializable<lock_type>;
+                requires !requires {
+                    [](const std::piecewise_construct_t, auto&&...) {}(std::declval<Args>()...);
+                };
+            }
         explicit(sizeof...(Args) == 1) constexpr synchronizer(Args&&... args) //
             noexcept(nothrow_constructible_from<value_type, Args...> && nothrow_default_initializable<lock_type>):
             value_(cpp_forward(args)...)
@@ -35,6 +42,37 @@ namespace stdsharp
 
         ~synchronizer() = default;
 
+    private:
+        template<typename ValueTuple, typename LockableTuple, std::size_t... I, std::size_t... J>
+        constexpr synchronizer(
+            ValueTuple&& value_tuple,
+            LockableTuple&& lockable_tuple,
+            std::index_sequence<I...> /*unused*/,
+            std::index_sequence<J...> /*unused*/
+        ):
+            value_(cpo::get_element<I>(cpp_forward(value_tuple))...),
+            lockable_(cpo::get_element<J>(cpp_forward(lockable_tuple))...)
+        {
+        }
+
+    public:
+        template<typename ValueTuple, typename LockableTuple>
+            requires piecewise_constructible_from<value_type, ValueTuple> &&
+            piecewise_constructible_from<lock_type, LockableTuple>
+        constexpr synchronizer(
+            const std::piecewise_construct_t /*unused*/,
+            ValueTuple&& value_tuple,
+            LockableTuple&& lockable_tuple
+        ):
+            synchronizer(
+                cpp_forward(value_tuple),
+                cpp_forward(lockable_tuple),
+                std::make_index_sequence<std::tuple_size_v<std::remove_cvref_t<ValueTuple>>>{},
+                std::make_index_sequence<std::tuple_size_v<std::remove_cvref_t<LockableTuple>>>{}
+            )
+        {
+        }
+
 #define STDSHARP_SYN_MEM(volatile_, ref)                                                       \
     template<typename... Args>                                                                 \
     constexpr void read(                                                                       \
@@ -43,7 +81,7 @@ namespace stdsharp
     ) const volatile_ ref                                                                      \
         requires std::constructible_from<std::shared_lock<lock_type>, lock_type&, Args...>     \
     {                                                                                          \
-        const std::shared_lock lock{lockable_, cpp_forward(args)...};                         \
+        const std::shared_lock lock{lockable_, cpp_forward(args)...};                          \
         invoke(cpp_forward(func), cpp_forward(*this).value_);                                  \
     }                                                                                          \
                                                                                                \
@@ -52,7 +90,7 @@ namespace stdsharp
         volatile_ ref                                                                          \
         requires std::constructible_from<std::unique_lock<lock_type>, lock_type&, Args...>     \
     {                                                                                          \
-        const std::unique_lock lock{lockable_, cpp_forward(args)...};                         \
+        const std::unique_lock lock{lockable_, cpp_forward(args)...};                          \
         invoke(cpp_forward(func), cpp_forward(*this).value_);                                  \
     }
 
diff --git a/include/stdsharp/type_traits/core_traits.h b/include/stdsharp/type_traits/core_traits.h
index d761a98..9b41252 100644
--- a/include/stdsharp/type_traits/core_traits.h
+++ b/include/stdsharp/type_traits/core_traits.h
@@ -521,12 +521,37 @@ namespace stdsharp::details
             STDSHARP_NO_UNIQUE_ADDRESS T v;
         };
     };
+
+    template<
+        typename T,
+        typename Tuple,
+        typename = std::make_index_sequence<std::tuple_size_v<Tuple>>>
+    struct piecewise_traits;
+
+    template<typename T, typename Tuple, std::size_t... I>
+    struct piecewise_traits<T, Tuple, std::index_sequence<I...>>
+    {
+        static constexpr auto constructible_from =
+            requires { requires std::constructible_from<T, get_element_t<I, Tuple>...>; };
+
+        static constexpr auto nothrow_constructible_from = requires {
+            requires std::is_nothrow_constructible_v<T, get_element_t<I, Tuple>...>;
+        };
+    };
 }
 
 namespace stdsharp
 {
     template<typename T>
     using ebo_union = details::ebo_union<T>::type;
+
+    template<typename T, typename Tuple>
+    concept piecewise_constructible_from = //
+        details::piecewise_traits<T, Tuple>::constructible_from;
+
+    template<typename T, typename Tuple>
+    concept piecewise_nothrow_constructible_from = //
+        details::piecewise_traits<T, Tuple>::nothrow_constructible_from;
 }
 
 namespace meta::extension