diff --git a/source/tanya/container/array.d b/source/tanya/container/array.d
index f884314..a13ec1e 100644
--- a/source/tanya/container/array.d
+++ b/source/tanya/container/array.d
@@ -21,8 +21,9 @@ import std.algorithm.mutation;
 import std.conv;
 import std.range.primitives;
 import std.meta;
-import std.traits;
 import tanya.memory;
+import tanya.meta.trait;
+import tanya.meta.transform;
 
 /**
  * Random-access range for the $(D_PSYMBOL Array).
diff --git a/source/tanya/container/buffer.d b/source/tanya/container/buffer.d
index b78d971..e29e739 100644
--- a/source/tanya/container/buffer.d
+++ b/source/tanya/container/buffer.d
@@ -14,8 +14,8 @@
  */
 module tanya.container.buffer;
 
-import std.traits;
 import tanya.memory;
+import tanya.meta.trait;
 
 version (unittest)
 {
diff --git a/source/tanya/container/entry.d b/source/tanya/container/entry.d
index 1aea478..75edbe8 100644
--- a/source/tanya/container/entry.d
+++ b/source/tanya/container/entry.d
@@ -14,7 +14,7 @@
  */
 module tanya.container.entry;
 
-import std.traits;
+import tanya.meta.trait;
 import tanya.typecons;
 
 package struct SEntry(T)
diff --git a/source/tanya/container/list.d b/source/tanya/container/list.d
index fc87ee4..97228ab 100644
--- a/source/tanya/container/list.d
+++ b/source/tanya/container/list.d
@@ -18,9 +18,9 @@ import std.algorithm.comparison;
 import std.algorithm.mutation;
 import std.algorithm.searching;
 import std.range.primitives;
-import std.traits;
 import tanya.container.entry;
 import tanya.memory;
+import tanya.meta.trait;
 
 /**
  * Forward range for the $(D_PSYMBOL SList).
diff --git a/source/tanya/container/queue.d b/source/tanya/container/queue.d
index d9b5609..2b07a6a 100644
--- a/source/tanya/container/queue.d
+++ b/source/tanya/container/queue.d
@@ -15,10 +15,10 @@
 module tanya.container.queue;
 
 import core.exception;
-import std.traits;
 import std.algorithm.mutation;
 import tanya.container.entry;
 import tanya.memory;
+import tanya.meta.trait;
 
 /**
  * FIFO queue.
diff --git a/source/tanya/container/set.d b/source/tanya/container/set.d
index 15ce7a4..1c5e559 100644
--- a/source/tanya/container/set.d
+++ b/source/tanya/container/set.d
@@ -16,10 +16,11 @@
 module tanya.container.set;
 
 import std.algorithm.mutation;
-import std.traits;
 import tanya.container;
 import tanya.container.entry;
 import tanya.memory;
+import tanya.meta.trait;
+import tanya.meta.transform;
 
 /**
  * Bidirectional range that iterates over the $(D_PSYMBOL Set)'s values.
diff --git a/source/tanya/container/string.d b/source/tanya/container/string.d
index 68c258b..6918e29 100644
--- a/source/tanya/container/string.d
+++ b/source/tanya/container/string.d
@@ -32,8 +32,9 @@ import std.algorithm.mutation;
 import std.algorithm.searching;
 import std.range : isInfinite, isInputRange, ElementEncodingType, hasLength,
                    popFrontN, empty;
-import std.traits;
 import tanya.memory;
+import tanya.meta.trait;
+import tanya.meta.transform;
 import tanya.range.array;
 
 /**
diff --git a/source/tanya/format/conv.d b/source/tanya/format/conv.d
index 77b84e3..ac5754a 100644
--- a/source/tanya/format/conv.d
+++ b/source/tanya/format/conv.d
@@ -14,10 +14,11 @@
  */
 module tanya.format.conv;
 
-import std.traits;
 import tanya.container.string;
 import tanya.memory;
 import tanya.memory.op;
+import tanya.meta.trait;
+import tanya.meta.transform;
 
 /**
  * Thrown if a type conversion fails.
diff --git a/source/tanya/memory/package.d b/source/tanya/memory/package.d
index 385aff9..fcb7dfa 100644
--- a/source/tanya/memory/package.d
+++ b/source/tanya/memory/package.d
@@ -19,9 +19,9 @@ import std.algorithm.iteration;
 import std.algorithm.mutation;
 import std.conv;
 import std.range;
-import std.traits;
 public import tanya.memory.allocator;
 import tanya.memory.mmappool;
+import tanya.meta.trait;
 
 /**
  * The mixin generates common methods for classes and structs using
diff --git a/source/tanya/memory/smartref.d b/source/tanya/memory/smartref.d
index 4883109..e33abcd 100644
--- a/source/tanya/memory/smartref.d
+++ b/source/tanya/memory/smartref.d
@@ -22,8 +22,8 @@ import std.algorithm.comparison;
 import std.algorithm.mutation;
 import std.conv;
 import std.range;
-import std.traits;
 import tanya.memory;
+import tanya.meta.trait;
 
 private template Payload(T)
 {
diff --git a/source/tanya/meta/trait.d b/source/tanya/meta/trait.d
index b4d4367..d6e2114 100644
--- a/source/tanya/meta/trait.d
+++ b/source/tanya/meta/trait.d
@@ -195,7 +195,7 @@ pure nothrow @safe @nogc unittest
  *  T = A type.
  *
  * Returns: Size of the type $(D_PARAM T).
- */ 
+ */
 enum size_t sizeOf(T) = T.sizeof;
 
 ///
@@ -391,7 +391,12 @@ version (TanyaPhobos)
                                TemplateArgsOf,
                                Parameters,
                                ParameterIdentifierTuple,
-                               functionAttributes;
+                               functionAttributes,
+                               ParameterDefaults,
+                               hasElaborateDestructor,
+                               hasElaborateCopyConstructor,
+                               hasElaborateAssign,
+                               EnumMembers;
 }
 else:
 
@@ -2330,3 +2335,295 @@ pure nothrow @safe @nogc unittest
     static assert((functionAttributes!func1 & FunctionAttribute.trusted) == 0);
     static assert((functionAttributes!func1 & FunctionAttribute.return_) == 0);
 }
+
+/**
+ * Returns a tuple with default values of the parameters to $(D_PARAM F).
+ *
+ * If a parameter doesn't have a default value, $(D_KEYWORD void) is returned.
+ *
+ * Params:
+ *  F = A function.
+ *
+ * Returns: Default values of the parameters to $(D_PARAM F).
+ */
+template ParameterDefaults(F...)
+if (isCallable!F)
+{
+    static if (is(FunctionTypeOf!F T == __parameters))
+    {
+        private template GetDefault(size_t i)
+        {
+            static if (i == T.length)
+            {
+                alias GetDefault = AliasSeq!();
+            }
+            else
+            {
+                enum getDefault(T[i .. i + 1] name)
+                {
+                    return name[0];
+                }
+                static if (is(typeof(getDefault())))
+                {
+                    alias Default = Alias!(getDefault());
+                }
+                else
+                {
+                    alias Default = void;
+                }
+                alias GetDefault = AliasSeq!(Default, GetDefault!(i + 1));
+            }
+        }
+
+        alias ParameterDefaults = GetDefault!0;
+    }
+}
+
+///
+pure nothrow @safe @nogc unittest
+{
+    void func1(int k, uint b = 5, int[] = [1, 2]);
+    alias Defaults = ParameterDefaults!func1;
+    static assert(is(Defaults[0] == void));
+    static assert(Defaults[1 .. 3] == AliasSeq!(5, [1, 2]));
+}
+
+/**
+ * Determines whether $(D_PARAM T) has an elaborate destructor.
+ *
+ * Only $(D_KEYWORD struct)s and static arrays of $(D_KEYWORD struct)s with the
+ * length greater than`0` can have elaborate destructors, for all other types
+ * $(D_PSYMBOL hasElaborateDestructor) evaluates to $(D_KEYWORD false).
+ *
+ * An elaborate destructor is an explicitly defined destructor or one generated
+ * by the compiler. The compiler generates a destructor for a
+ * $(D_KEYWORD struct) if it has members with an elaborate destructor.
+ *
+ * Params:
+ *  T = A type.
+ *
+ * Returns: $(D_KEYWORD true) if $(D_PARAM T) has an elaborate destructor,
+ *          $(D_KEYWORD false) otherwise.
+ */
+template hasElaborateDestructor(T)
+{
+    static if (is(T E : E[L], size_t L))
+    {
+        enum bool hasElaborateDestructor = L > 0 && hasElaborateDestructor!E;
+    }
+    else
+    {
+        enum bool hasElaborateDestructor = is(T == struct)
+                                        && hasMember!(T, "__xdtor");
+    }
+}
+
+///
+pure nothrow @safe @nogc unittest
+{
+    class C
+    {
+        ~this()
+        {
+        }
+    }
+    static assert(!hasElaborateDestructor!C);
+
+    static struct S
+    {
+        ~this()
+        {
+        }
+    }
+    static struct S1
+    {
+        S s;
+    }
+    static struct S2
+    {
+    }
+    static assert(hasElaborateDestructor!S); // Explicit destructor.
+    static assert(hasElaborateDestructor!S1); // Compiler-generated destructor.
+    static assert(!hasElaborateDestructor!S2); // No destructor.
+
+    static assert(hasElaborateDestructor!(S[1]));
+    static assert(!hasElaborateDestructor!(S[0]));
+}
+
+/**
+ * Determines whether $(D_PARAM T) has an elaborate postblit constructor.
+ *
+ * Only $(D_KEYWORD struct)s and static arrays of $(D_KEYWORD struct)s with the
+ * length greater than`0` can have elaborate postblit constructors, for all
+ * other types $(D_PSYMBOL hasElaborateCopyConstructor) evaluates to
+ * $(D_KEYWORD false).
+ *
+ * An elaborate postblit constructor is an explicitly defined postblit
+ * constructor or one generated by the compiler. The compiler generates a
+ * postblit constructor for a
+ * $(D_KEYWORD struct) if it has members with an elaborate postblit
+ * constructor.
+ *
+ * Params:
+ *  T = A type.
+ *
+ * Returns: $(D_KEYWORD true) if $(D_PARAM T) has an elaborate postblit
+ *          constructor, $(D_KEYWORD false) otherwise.
+ */
+template hasElaborateCopyConstructor(T)
+{
+    static if (is(T E : E[L], size_t L))
+    {
+        enum bool hasElaborateCopyConstructor = L > 0
+                                             && hasElaborateCopyConstructor!E;
+    }
+    else
+    {
+        enum bool hasElaborateCopyConstructor = is(T == struct)
+                                             && hasMember!(T, "__xpostblit");
+    }
+}
+
+///
+pure nothrow @safe @nogc unittest
+{
+    static assert(!hasElaborateCopyConstructor!int);
+
+    static struct S
+    {
+        this(this)
+        {
+        }
+    }
+    static struct S1
+    {
+        S s;
+    }
+    static struct S2
+    {
+    }
+    static assert(hasElaborateCopyConstructor!S); // Explicit destructor.
+    static assert(hasElaborateCopyConstructor!S1); // Compiler-generated destructor.
+    static assert(!hasElaborateCopyConstructor!S2); // No destructor.
+    static assert(hasElaborateCopyConstructor!(S[1]));
+    static assert(!hasElaborateCopyConstructor!(S[0]));
+}
+
+/**
+ * Determines whether $(D_PARAM T) has an elaborate assign.
+ *
+ * Only $(D_KEYWORD struct)s and static arrays of $(D_KEYWORD struct)s with the
+ * length greater than`0` can have an elaborate assign, for all
+ * other types $(D_PSYMBOL hasElaborateAssign) evaluates to $(D_KEYWORD false).
+ *
+ * An elaborate assign is defined with $(D_INLINECODE opAssign(typeof(this)))
+ * or $(D_INLINECODE opAssign(ref typeof(this))). An elaborate assign can be
+ * generated for a $(D_KEYWORD struct) by the compiler if one of the members of
+ * this $(D_KEYWORD struct) has an elaborate assign.
+ *
+ * Params:
+ *  T = A type.
+ *
+ * Returns: $(D_KEYWORD true) if $(D_PARAM T) has an elaborate assign,
+ *          $(D_KEYWORD false) otherwise.
+ */
+template hasElaborateAssign(T)
+{
+    static if (is(T E : E[L], size_t L))
+    {
+        enum bool hasElaborateAssign = L > 0 && hasElaborateAssign!E;
+    }
+    else static if (is(T == struct))
+    {
+        private enum bool valueAssign = is(typeof({ T.init.opAssign(T()); }));
+        enum bool hasElaborateAssign = valueAssign || is(typeof({
+            T s;
+            s.opAssign(s);
+        }));
+    }
+    else
+    {
+        enum bool hasElaborateAssign = false;
+    }
+}
+
+pure nothrow @safe @nogc unittest
+{
+    static assert(!hasElaborateAssign!int);
+
+    static struct S1
+    {
+        void opAssign(S1)
+        {
+        }
+    }
+    static struct S2
+    {
+        void opAssign(int)
+        {
+        }
+    }
+    static struct S3
+    {
+        S1 s;
+        alias s this;
+    }
+    static assert(hasElaborateAssign!S1);
+    static assert(!hasElaborateAssign!(const S1));
+    static assert(hasElaborateAssign!(S1[1]));
+    static assert(!hasElaborateAssign!(S1[0]));
+    static assert(!hasElaborateAssign!S2);
+    static assert(hasElaborateAssign!S3);
+
+    static struct S4
+    {
+        void opAssign(S4)
+        {
+        }
+        @disable this(this);
+    }
+    static assert(hasElaborateAssign!S4);
+}
+
+/**
+ * Returns all members of $(D_KEYWORD enum) $(D_PARAM T).
+ *
+ * The members of $(D_PARAM T) are typed as $(D_PARAM T), not as a base type
+ * of the enum.
+ *
+ * $(D_PARAM EnumMembers) returns all members of $(D_PARAM T), also if there
+ * are some duplicates.
+ *
+ * Params:
+ *  T = A $(D_KEYWORD enum).
+ *
+ * Returns: All members of $(D_PARAM T).
+ */
+template EnumMembers(T)
+if (is(T == enum))
+{
+    private template getEnumMembers(Args...)
+    {
+        static if (Args.length == 1)
+        {
+            enum T getEnumMembers = __traits(getMember, T, Args[0]);
+        }
+        else
+        {
+            alias getEnumMembers = AliasSeq!(__traits(getMember, T, Args[0]), getEnumMembers!(Args[1 .. $]));
+        }
+    }
+    alias EnumMembers = getEnumMembers!(__traits(allMembers, T));
+}
+
+///
+pure nothrow @nogc @safe unittest
+{
+    enum E : int
+    {
+        one,
+        two,
+        three,
+    }
+    static assert([E.one, E.two, E.three] == [ EnumMembers!E ]);
+}