[over.match] - C++14 → C++17

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@@ -5,14 +5,16 @@ call given a list of expressions that are to be the arguments of the
 call and a set of *candidate functions* that can be called based on the
 context of the call. The selection criteria for the best function are
 the number of arguments, how well the arguments match the
 parameter-type-list of the candidate function, how well (for non-static
 member functions) the object matches the implicit object parameter, and
-certain other properties of the candidate function. The function
-selected by overload resolution is not guaranteed to be appropriate for
-the context. Other restrictions, such as the accessibility of the
-function, can make its use in the calling context ill-formed.
 Overload resolution selects the function to call in seven distinct
 contexts within the language:
 - invocation of a function named in the function call syntax (
@@ -21,16 +23,16 @@ contexts within the language:
   conversion function, a reference-to-pointer-to-function conversion
   function, or a reference-to-function conversion function on a class
   object named in the function call syntax ([[over.call.object]]);
 - invocation of the operator referenced in an expression (
   [[over.match.oper]]);
-- invocation of a constructor for direct-initialization ([[dcl.init]])
-  of a class object ([[over.match.ctor]]);
 - invocation of a user-defined conversion for copy-initialization (
   [[dcl.init]]) of a class object ([[over.match.copy]]);
 - invocation of a conversion function for initialization of an object of
-  a nonclass type from an expression of class type (
   [[over.match.conv]]); and
 - invocation of a conversion function for conversion to a glvalue or
   class prvalue to which a reference ([[dcl.init.ref]]) will be
   directly bound ([[over.match.ref]]).
@@ -80,55 +82,56 @@ object parameter, if present, is always the first parameter and the
 implied object argument, if present, is always the first argument.
 For non-static member functions, the type of the implicit object
 parameter is
-- “lvalue reference to *cv* `X`” for functions declared without a
   *ref-qualifier* or with the `&` *ref-qualifier*
-- “rvalue reference to *cv* `X`” for functions declared with the `&&`
   *ref-qualifier*
-where `X` is the class of which the function is a member and *cv* is the
-cv-qualification on the member function declaration. for a `const`
-member function of class `X`, the extra parameter is assumed to have
-type “reference to `const X`”. For conversion functions, the function is
-considered to be a member of the class of the implied object argument
-for the purpose of defining the type of the implicit object parameter.
-For non-conversion functions introduced by a *using-declaration* into a
-derived class, the function is considered to be a member of the derived
-class for the purpose of defining the type of the implicit object
-parameter. For static member functions, the implicit object parameter is
-considered to match any object (since if the function is selected, the
-object is discarded). No actual type is established for the implicit
-object parameter of a static member function, and no attempt will be
-made to determine a conversion sequence for that parameter (
-[[over.match.best]]).
 During overload resolution, the implied object argument is
 indistinguishable from other arguments. The implicit object parameter,
-however, retains its identity since conversions on the corresponding
-argument shall obey these additional rules:
-- no temporary object can be introduced to hold the argument for the
-  implicit object parameter; and
-- no user-defined conversions can be applied to achieve a type match
-  with it.
-For non-static member functions declared without a *ref-qualifier*, an
-additional rule applies:
-- even if the implicit object parameter is not `const`-qualified, an
   rvalue can be bound to the parameter as long as in all other respects
   the argument can be converted to the type of the implicit object
-  parameter. The fact that such an argument is an rvalue does not affect
-  the ranking of implicit conversion sequences ([[over.ics.rank]]).
 Because other than in list-initialization only one user-defined
 conversion is allowed in an implicit conversion sequence, special rules
 apply when selecting the best user-defined conversion (
 [[over.match.best]], [[over.best.ics]]).
 ``` cpp
 class T {
 public:
   T();
 };
@@ -138,10 +141,12 @@ public:
   C(int);
 };
 T a = 1;            // ill-formed: T(C(1)) not tried
 ```
 In each case where a candidate is a function template, candidate
 function template specializations are generated using template argument
 deduction ([[temp.over]], [[temp.deduct]]). Those candidates are then
 handled as candidate functions in the usual way.[^2] A given name can
 refer to one or more function templates and also to a set of overloaded
@@ -169,12 +174,13 @@ class type, overload resolution is applied as specified in
 If the *postfix-expression* denotes the address of a set of overloaded
 functions and/or function templates, overload resolution is applied
 using that set as described above. If the function selected by overload
 resolution is a non-static member function, the program is ill-formed.
-The resolution of the address of an overload set in other contexts is
-described in [[over.over]].
 ##### Call to named function <a id="over.call.func">[[over.call.func]]</a>
 Of interest in  [[over.call.func]] are only those function calls in
 which the *postfix-expression* ultimately contains a name that denotes
@@ -197,12 +203,12 @@ In qualified function calls, the name to be resolved is an
 construct `A->B` is generally equivalent to `(*A).B`, the rest of
 Clause  [[over]] assumes, without loss of generality, that all member
 function calls have been normalized to the form that uses an object and
 the `.` operator. Furthermore, Clause  [[over]] assumes that the
 *postfix-expression* that is the left operand of the `.` operator has
-type “*cv* `T`” where `T` denotes a class[^3]. Under this assumption,
-the *id-expression* in the call is looked up as a member function of `T`
 following the rules for looking up names in classes (
 [[class.member.lookup]]). The function declarations found by that lookup
 constitute the set of candidate functions. The argument list is the
 *expression-list* in the call augmented by the addition of the left
 operand of the `.` operator in the normalized member function call as
@@ -228,32 +234,33 @@ and overload resolution selects one of the non-static member functions
 of `T`, the call is ill-formed.
 ##### Call to object of class type <a id="over.call.object">[[over.call.object]]</a>
 If the *primary-expression* `E` in the function call syntax evaluates to
-a class object of type “*cv* `T`”, then the set of candidate functions
 includes at least the function call operators of `T`. The function call
 operators of `T` are obtained by ordinary lookup of the name
 `operator()` in the context of `(E).operator()`.
 In addition, for each non-explicit conversion function declared in `T`
 of the form
 ``` bnf
-'operator' conversion-type-id '( )' cv-qualifier ref-qualifierₒₚₜ exception-specificationₒₚₜ attribute-specifier-seqₒₚₜ ';'
 ```
 where *cv-qualifier* is the same cv-qualification as, or a greater
-cv-qualification than, *cv*, and where *conversion-type-id* denotes the
-type “pointer to function of (`P1`,...,`Pn)` returning `R`”, or the type
-“reference to pointer to function of (`P1`,...,`Pn)` returning `R`”, or
-the type “reference to function of (`P1`,...,`Pn)` returning `R`”, a
 *surrogate call function* with the unique name *call-function* and
 having the form
 ``` bnf
-'R' call-function '(' conversion-type-id 'F, P1 a1, ... ,Pn an)' '{ return F (a1,... ,an); }'
 ```
 is also considered as a candidate function. Similarly, surrogate call
 functions are added to the set of candidate functions for each
 non-explicit conversion function declared in a base class of `T`
@@ -267,82 +274,92 @@ then be invoked with the arguments of the call. If the conversion
 function cannot be called (e.g., because of an ambiguity), the program
 is ill-formed.
 The argument list submitted to overload resolution consists of the
 argument expressions present in the function call syntax preceded by the
-implied object argument `(E)`. When comparing the call against the
-function call operators, the implied object argument is compared against
-the implicit object parameter of the function call operator. When
-comparing the call against a surrogate call function, the implied object
-argument is compared against the first parameter of the surrogate call
-function. The conversion function from which the surrogate call function
-was derived will be used in the conversion sequence for that parameter
-since it converts the implied object argument to the appropriate
-function pointer or reference required by that first parameter.
 ``` cpp
 int f1(int);
 int f2(float);
 typedef int (*fp1)(int);
 typedef int (*fp2)(float);
 struct A {
   operator fp1() { return f1; }
   operator fp2() { return f2; }
 } a;
-int i = a(1); // calls f1 via pointer returned from
-                    // conversion function
 ```
 #### Operators in expressions <a id="over.match.oper">[[over.match.oper]]</a>
 If no operand of an operator in an expression has a type that is a class
 or an enumeration, the operator is assumed to be a built-in operator and
-interpreted according to Clause  [[expr]]. Because `.`, `.*`, and `::`
-cannot be overloaded, these operators are always built-in operators
-interpreted according to Clause  [[expr]]. `?:` cannot be overloaded,
-but the rules in this subclause are used to determine the conversions to
-be applied to the second and third operands when they have class or
-enumeration type ([[expr.cond]]).
 ``` cpp
 struct String {
   String (const String&);
   String (const char*);
   operator const char* ();
 };
 String operator + (const String&, const String&);
-void f(void) {
- const char* p= "one" + "two";  // ill-formed because neither
- // operand has class or enumeration type
- int I = 1 + 1;                 // Always evaluates to 2 even if
-                                // class or enumeration types exist that
-                                // would perform the operation.
 }
 ```
 If either operand has a type that is a class or an enumeration, a
 user-defined operator function might be declared that implements this
 operator or a user-defined conversion can be necessary to convert the
 operand to a type that is appropriate for a built-in operator. In this
 case, overload resolution is used to determine which operator function
 or built-in operator is to be invoked to implement the operator.
 Therefore, the operator notation is first transformed to the equivalent
 function-call notation as summarized in Table  [[tab:over.rel.op.func]]
 (where `@` denotes one of the operators covered in the specified
-subclause).
 **Table: Relationship between operator and function call notation** <a id="tab:over.rel.op.func">[tab:over.rel.op.func]</a>
 | Subclause    | Expression | As member function  | As non-member function |
-| ------------ | ---------- | ------------------ | ---------------------- |
-| (a) |
-| (a, b) |
-| [[over.ass]] | a=b | (a).operator= (b) |                        |
-| [[over.sub]] | a[b] | (a).operator[](b) |                        |
-| [[over.ref]] | a-> | (a).operator-> ( ) |                        |
-| (a, 0) |
 For a unary operator `@` with an operand of a type whose cv-unqualified
 version is `T1`, and for a binary operator `@` with a left operand of a
 type whose cv-unqualified version is `T1` and a right operand of a type
@@ -358,14 +375,14 @@ candidates*, are constructed as follows:
   lookup of `operator@` in the context of the expression according to
   the usual rules for name lookup in unqualified function calls (
   [[basic.lookup.argdep]]) except that all member functions are ignored.
   However, if no operand has a class type, only those non-member
   functions in the lookup set that have a first parameter of type `T1`
-  or “reference to (possibly cv-qualified) `T1`”, when `T1` is an
- enumeration type, or (if there is a right operand) a second parameter
- of type `T2` or “reference to (possibly cv-qualified) `T2`”, when `T2`
- is an enumeration type, are candidate functions.
 - For the operator `,`, the unary operator `&`, or the operator `->`,
   the built-in candidates set is empty. For all other operators, the
   built-in candidates include all of the candidate operator functions
   defined in  [[over.built]] that, compared to the given operator,
   - have the same operator name, and
@@ -389,10 +406,12 @@ the member candidates, the non-member candidates, and the built-in
 candidates. The argument list contains all of the operands of the
 operator. The best function from the set of candidate functions is
 selected according to  [[over.match.viable]] and
 [[over.match.best]].[^6]
 ``` cpp
 struct A {
   operator int();
 };
 A operator+(const A&, const A&);
@@ -400,18 +419,22 @@ void m() {
   A a, b;
   a + b;                        // operator+(a, b) chosen over int(a) + int(b)
 }
 ```
 If a built-in candidate is selected by overload resolution, the operands
 of class type are converted to the types of the corresponding parameters
 of the selected operation function, except that the second standard
 conversion sequence of a user-defined conversion sequence (
 [[over.ics.user]]) is not applied. Then the operator is treated as the
 corresponding built-in operator and interpreted according to Clause
 [[expr]].
 ``` cpp
 struct X {
   operator double();
 };
@@ -421,20 +444,24 @@ struct Y {
 int *a = Y() + 100.0;           // error: pointer arithmetic requires integral operand
 int *b = Y() + X();             // error: pointer arithmetic requires integral operand
 ```
 The second operand of operator `->` is ignored in selecting an
 `operator->` function, and is not an argument when the `operator->`
 function is called. When `operator->` returns, the operator `->` is
 applied to the value returned, with the original second operand.[^7]
 If the operator is the operator `,`, the unary operator `&`, or the
 operator `->`, and there are no viable functions, then the operator is
 assumed to be the built-in operator and interpreted according to Clause
 [[expr]].
 The lookup rules for operators in expressions are different than the
 lookup rules for operator function names in a function call, as shown in
 the following example:
 ``` cpp
@@ -452,64 +479,72 @@ void B::f() {
   operator+ (a,a);              // error: global operator hidden by member
   a + a;                        // OK: calls global operator+
 }
 ```
 #### Initialization by constructor <a id="over.match.ctor">[[over.match.ctor]]</a>
-When objects of class type are direct-initialized ([[dcl.init]]), or
 copy-initialized from an expression of the same or a derived class
-type ([[dcl.init]]), overload resolution selects the constructor. For
-direct-initialization, the candidate functions are all the constructors
-of the class of the object being initialized. For copy-initialization,
-the candidate functions are all the converting constructors (
 [[class.conv.ctor]]) of that class. The argument list is the
 *expression-list* or *assignment-expression* of the *initializer*.
 #### Copy-initialization of class by user-defined conversion <a id="over.match.copy">[[over.match.copy]]</a>
 Under the conditions specified in  [[dcl.init]], as part of a
 copy-initialization of an object of class type, a user-defined
 conversion can be invoked to convert an initializer expression to the
 type of the object being initialized. Overload resolution is used to
-select the user-defined conversion to be invoked. The conversion
-performed for indirect binding to a reference to a possibly cv-qualified
-class type is determined in terms of a corresponding non-reference
-copy-initialization. Assuming that “*cv1* `T`” is the type of the object
-being initialized, with `T` a class type, the candidate functions are
-selected as follows:
 - The converting constructors ([[class.conv.ctor]]) of `T` are
   candidate functions.
-- When the type of the initializer expression is a class type “*cv*
- `S`”, the non-explicit conversion functions of `S` and its base
- classes are considered. When initializing a temporary to be bound to
- the first parameter of a constructor that takes a reference to
-  possibly cv-qualified `T` as its first argument, called with a single
-  argument in the context of direct-initialization of an object of type
-  “*cv2* `T`”, explicit conversion functions are also considered. Those
-  that are not hidden within `S` and yield a type whose cv-unqualified
-  version is the same type as `T` or is a derived class thereof are
-  candidate functions. Conversion functions that return “reference to
-  `X`” return lvalues or xvalues, depending on the type of reference, of
-  type `X` and are therefore considered to yield `X` for this process of
-  selecting candidate functions.
 In both cases, the argument list has one argument, which is the
-initializer expression. This argument will be compared against the first
-parameter of the constructors and against the implicit object parameter
-of the conversion functions.
 #### Initialization by conversion function <a id="over.match.conv">[[over.match.conv]]</a>
 Under the conditions specified in  [[dcl.init]], as part of an
-initialization of an object of nonclass type, a conversion function can
 be invoked to convert an initializer expression of class type to the
 type of the object being initialized. Overload resolution is used to
 select the conversion function to be invoked. Assuming that “*cv1* `T`”
-is the type of the object being initialized, and “*cv* `S`” is the type
-of the initializer expression, with `S` a class type, the candidate
 functions are selected as follows:
 - The conversion functions of `S` and its base classes are considered.
   Those non-explicit conversion functions that are not hidden within `S`
   and yield type `T` or a type that can be converted to type `T` via a
@@ -524,46 +559,50 @@ functions are selected as follows:
   return lvalues or xvalues, depending on the type of reference, of type
   “*cv2* `X`” and are therefore considered to yield `X` for this process
   of selecting candidate functions.
 The argument list has one argument, which is the initializer expression.
-This argument will be compared against the implicit object parameter of
-the conversion functions.
 #### Initialization by conversion function for direct reference binding <a id="over.match.ref">[[over.match.ref]]</a>
 Under the conditions specified in  [[dcl.init.ref]], a reference can be
 bound directly to a glvalue or class prvalue that is the result of
 applying a conversion function to an initializer expression. Overload
 resolution is used to select the conversion function to be invoked.
-Assuming that “*cv1* `T`” is the underlying type of the reference being
-initialized, and “*cv* `S`” is the type of the initializer expression,
-with `S` a class type, the candidate functions are selected as follows:
 - The conversion functions of `S` and its base classes are considered.
   Those non-explicit conversion functions that are not hidden within `S`
   and yield type “lvalue reference to *cv2* `T2`” (when initializing an
-  lvalue reference or an rvalue reference to function) or “ `T2`” or
-  “rvalue reference to `T2`” (when initializing an rvalue reference or
-  an lvalue reference to function), where “*cv1* `T`” is
   reference-compatible ([[dcl.init.ref]]) with “*cv2* `T2`”, are
   candidate functions. For direct-initialization, those explicit
   conversion functions that are not hidden within `S` and yield type
   “lvalue reference to *cv2* `T2`” or “*cv2* `T2`” or “rvalue reference
-  to *cv2* `T2`,” respectively, where `T2` is the same type as `T` or
   can be converted to type `T` with a qualification conversion (
   [[conv.qual]]), are also candidate functions.
 The argument list has one argument, which is the initializer expression.
-This argument will be compared against the implicit object parameter of
-the conversion functions.
 #### Initialization by list-initialization <a id="over.match.list">[[over.match.list]]</a>
-When objects of non-aggregate class type `T` are list-initialized (
-[[dcl.init.list]]), overload resolution selects the constructor in two
-phases:
 - Initially, the candidate functions are the initializer-list
   constructors ([[dcl.init.list]]) of the class `T` and the argument
   list consists of the initializer list as a single argument.
 - If no viable initializer-list constructor is found, overload
@@ -572,14 +611,89 @@ phases:
   the elements of the initializer list.
 If the initializer list has no elements and `T` has a default
 constructor, the first phase is omitted. In copy-list-initialization, if
 an `explicit` constructor is chosen, the initialization is ill-formed.
-This differs from other situations ([[over.match.ctor]],
 [[over.match.copy]]), where only converting constructors are considered
 for copy-initialization. This restriction only applies if this
-initialization is part of the final result of overload resolution.
 ### Viable functions <a id="over.match.viable">[[over.match.viable]]</a>
 From the set of candidate functions constructed for a given context (
 [[over.match.funcs]]), a set of viable functions is chosen, from which
@@ -615,14 +729,14 @@ function (see  [[over.ics.ref]]).
 ### Best viable function <a id="over.match.best">[[over.match.best]]</a>
 Define ICS*i*(`F`) as follows:
-- if `F` is a static member function, ICS*1*(`F`) is defined such that
   ICS*1*(`F`) is neither better nor worse than ICS*1*(`G`) for any
   function `G`, and, symmetrically, ICS*1*(`G`) is neither better nor
-  worse than ICS*1*(`F`)[^9]; otherwise,
 - let ICS*i*(`F`) denote the implicit conversion sequence that converts
   the *i*-th argument in the list to the type of the *i*-th parameter of
   viable function `F`. [[over.best.ics]] defines the implicit conversion
   sequences and [[over.ics.rank]] defines what it means for one implicit
   conversion sequence to be a better conversion sequence or worse
@@ -638,30 +752,32 @@ and then
 - the context is an initialization by user-defined conversion (see
   [[dcl.init]], [[over.match.conv]], and  [[over.match.ref]]) and the
   standard conversion sequence from the return type of `F1` to the
   destination type (i.e., the type of the entity being initialized) is a
   better conversion sequence than the standard conversion sequence from
-  the return type of `F2` to the destination type.
   ``` cpp
   struct A {
     A();
     operator int();
     operator double();
   } a;
-  int i = a; // a.operator int() followed by no conversion
- // is better than a.operator double() followed by
-                                  // a conversion to int
   float x = a;        // ambiguous: both possibilities require conversions,
                       // and neither is better than the other
   ```
   or, if not that,
 - the context is an initialization by conversion function for direct
   reference binding ([[over.match.ref]]) of a reference to function
   type, the return type of `F1` is the same kind of reference (i.e.
   lvalue or rvalue) as the reference being initialized, and the return
   type of `F2` is not
   ``` cpp
   template <class T> struct A {
     operator T&();    // #1
     operator T&&();   // #2
   };
@@ -669,50 +785,87 @@ and then
   A<Fn> a;
   Fn& lf = a;         // calls #1
   Fn&& rf = a;        // calls #2
   ```
   or, if not that,
 - `F1` is not a function template specialization and `F2` is a function
   template specialization, or, if not that,
 - `F1` and `F2` are function template specializations, and the function
   template for `F1` is more specialized than the template for `F2`
   according to the partial ordering rules described in
-  [[temp.func.order]].
 If there is exactly one viable function that is a better function than
 all other viable functions, then it is the one selected by overload
-resolution; otherwise the call is ill-formed[^10].
 ``` cpp
 void Fcn(const int*,  short);
 void Fcn(int*, int);
 int i;
 short s = 0;
 void f() {
-  Fcn(&i, s); // is ambiguous because
-                                // &i → int* is better than &i → const int*
                     // but s → short is also better than s → int
-  Fcn(&i, 1L); // calls Fcn(int*, int), because
-                                // &i → int* is better than &i → const int*
                     // and 1L → short and 1L → int are indistinguishable
-  Fcn(&i,'c'); // calls Fcn(int*, int), because
-                                // &i → int* is better than &i → const int*
                     // and c → int is better than c → short
 }
 ```
 If the best viable function resolves to a function for which multiple
 declarations were found, and if at least two of these declarations — or
 the declarations they refer to in the case of *using-declaration*s —
 specify a default argument that made the function viable, the program is
 ill-formed.
 ``` cpp
 namespace A {
   extern "C" void f(int = 5);
 }
 namespace B {
@@ -726,10 +879,12 @@ void use() {
   f(3);             // OK, default argument was not used for viability
   f();              // Error: found default argument twice
 }
 ```
 #### Implicit conversion sequences <a id="over.best.ics">[[over.best.ics]]</a>
 An *implicit conversion sequence* is a sequence of conversions used to
 convert an argument in a function call to the type of the corresponding
 parameter of the function being called. The sequence of conversions is
@@ -738,16 +893,16 @@ governed by the rules for initialization of an object or reference by a
 single expression ([[dcl.init]], [[dcl.init.ref]]).
 Implicit conversion sequences are concerned only with the type,
 cv-qualification, and value category of the argument and how these are
 converted to match the corresponding properties of the parameter. Other
-properties, such as the lifetime, storage class, alignment, or
-accessibility of the argument and whether or not the argument is a
-bit-field are ignored. So, although an implicit conversion sequence can
-be defined for a given argument-parameter pair, the conversion from the
-argument to the parameter might still be ill-formed in the final
-analysis.
 A well-formed implicit conversion sequence is one of the following
 forms:
 - a *standard conversion sequence* ([[over.ics.scs]]),
@@ -765,17 +920,21 @@ by
 -  [[over.match.ctor]], when the argument is the temporary in the second
   step of a class copy-initialization,
 -  [[over.match.copy]], [[over.match.conv]], or [[over.match.ref]] (in
   all cases), or
 - the second phase of [[over.match.list]] when the initializer list has
-  exactly one element, and the target is the first parameter of a
- constructor of class `X`, and the conversion is to `X` or reference to
- (possibly cv-qualified) `X`,
-user-defined conversion sequences are not considered. These rules
-prevent more than one user-defined conversion from being applied during
-overload resolution, thereby avoiding infinite recursion.
 ``` cpp
   struct Y { Y(int); };
   struct A { operator int(); };
   Y y1 = A();       // error: A::operator int() is not a candidate
@@ -784,83 +943,120 @@ struct Y { Y(int); };
   struct B { operator X(); };
   B b;
   X x({b});         // error: B::operator X() is not a candidate
 ```
 For the case where the parameter type is a reference, see
 [[over.ics.ref]].
 When the parameter type is not a reference, the implicit conversion
 sequence models a copy-initialization of the parameter from the argument
 expression. The implicit conversion sequence is the one required to
 convert the argument expression to a prvalue of the type of the
-parameter. When the parameter has a class type, this is a conceptual
 conversion defined for the purposes of Clause  [[over]]; the actual
 initialization is defined in terms of constructors and is not a
-conversion. Any difference in top-level cv-qualification is subsumed by
-the initialization itself and does not constitute a conversion. a
-parameter of type `A` can be initialized from an argument of type
-`const A`. The implicit conversion sequence for that case is the
-identity sequence; it contains no “conversion” from `const A` to `A`.
 When the parameter has a class type and the argument expression has the
 same type, the implicit conversion sequence is an identity conversion.
 When the parameter has a class type and the argument expression has a
 derived class type, the implicit conversion sequence is a
 derived-to-base Conversion from the derived class to the base class.
-There is no such standard conversion; this derived-to-base Conversion
-exists only in the description of implicit conversion sequences. A
-derived-to-base Conversion has Conversion rank ([[over.ics.scs]]).
 In all contexts, when converting to the implicit object parameter or
 when converting to the left operand of an assignment operation only
-standard conversion sequences that create no temporary object for the
-result are allowed.
 If no conversions are required to match an argument to a parameter type,
 the implicit conversion sequence is the standard conversion sequence
 consisting of the identity conversion ([[over.ics.scs]]).
 If no sequence of conversions can be found to convert an argument to a
-parameter type or the conversion is otherwise ill-formed, an implicit
-conversion sequence cannot be formed.
 If several different sequences of conversions exist that each convert
 the argument to the parameter type, the implicit conversion sequence
 associated with the parameter is defined to be the unique conversion
 sequence designated the *ambiguous conversion sequence*. For the purpose
 of ranking implicit conversion sequences as described in
 [[over.ics.rank]], the ambiguous conversion sequence is treated as a
-user-defined sequence that is indistinguishable from any other
-user-defined conversion sequence[^11]. If a function that uses the
-ambiguous conversion sequence is selected as the best viable function,
-the call will be ill-formed because the conversion of one of the
-arguments in the call is ambiguous.
 The three forms of implicit conversion sequences mentioned above are
 defined in the following subclauses.
 ##### Standard conversion sequences <a id="over.ics.scs">[[over.ics.scs]]</a>
 Table  [[tab:over.conversions]] summarizes the conversions defined in
 Clause  [[conv]] and partitions them into four disjoint categories:
 Lvalue Transformation, Qualification Adjustment, Promotion, and
-Conversion. These categories are orthogonal with respect to value
 category, cv-qualification, and data representation: the Lvalue
 Transformations do not change the cv-qualification or data
 representation of the type; the Qualification Adjustments do not change
 the value category or data representation of the type; and the
 Promotions and Conversions do not change the value category or
-cv-qualification of the type.
-As described in Clause  [[conv]], a standard conversion sequence is
-either the Identity conversion by itself (that is, no conversion) or
-consists of one to three conversions from the other four categories. At
-most one conversion from each category is allowed in a single standard
-conversion sequence. If there are two or more conversions in the
-sequence, the conversions are applied in the canonical order: **Lvalue
 Transformation**, **Promotion** or **Conversion**, **Qualification
-Adjustment**.
 Each conversion in Table  [[tab:over.conversions]] also has an
 associated rank (Exact Match, Promotion, or Conversion). These are used
 to rank standard conversion sequences ([[over.ics.rank]]). The rank of
 a conversion sequence is determined by considering the rank of each
@@ -921,70 +1117,88 @@ When a parameter of reference type binds directly ([[dcl.init.ref]]) to
 an argument expression, the implicit conversion sequence is the identity
 conversion, unless the argument expression has a type that is a derived
 class of the parameter type, in which case the implicit conversion
 sequence is a derived-to-base Conversion ([[over.best.ics]]).
 ``` cpp
 struct A {};
 struct B : public A {} b;
 int f(A&);
 int f(B&);
-int i = f(b); // calls f(B&), an exact match, rather than
-                                // f(A&), a conversion
 ```
 If the parameter binds directly to the result of applying a conversion
 function to the argument expression, the implicit conversion sequence is
 a user-defined conversion sequence ([[over.ics.user]]), with the second
 standard conversion sequence either an identity conversion or, if the
 conversion function returns an entity of a type that is a derived class
 of the parameter type, a derived-to-base Conversion.
 When a parameter of reference type is not bound directly to an argument
 expression, the conversion sequence is the one required to convert the
-argument expression to the underlying type of the reference according
-to  [[over.best.ics]]. Conceptually, this conversion sequence
-corresponds to copy-initializing a temporary of the underlying type with
-the argument expression. Any difference in top-level cv-qualification is
-subsumed by the initialization itself and does not constitute a
-conversion.
 Except for an implicit object parameter, for which see
 [[over.match.funcs]], a standard conversion sequence cannot be formed if
 it requires binding an lvalue reference other than a reference to a
 non-volatile `const` type to an rvalue or binding an rvalue reference to
-an lvalue other than a function lvalue. This means, for example, that a
-candidate function cannot be a viable function if it has a non-`const`
-lvalue reference parameter (other than the implicit object parameter)
-and the corresponding argument is a temporary or would require one to be
-created to initialize the lvalue reference (see  [[dcl.init.ref]]).
 Other restrictions on binding a reference to a particular argument that
 are not based on the types of the reference and the argument do not
-affect the formation of a standard conversion sequence, however. a
-function with an “lvalue reference to `int`” parameter can be a viable
-candidate even if the corresponding argument is an `int` bit-field. The
-formation of implicit conversion sequences treats the `int` bit-field as
-an `int` lvalue and finds an exact match with the parameter. If the
-function is selected by overload resolution, the call will nonetheless
-be ill-formed because of the prohibition on binding a non-`const` lvalue
-reference to a bit-field ([[dcl.init.ref]]).
 ##### List-initialization sequence <a id="over.ics.list">[[over.ics.list]]</a>
 When an argument is an initializer list ([[dcl.init.list]]), it is not
 an expression and special rules apply for converting it to a parameter
 type.
-If the parameter type is `std::initializer_list<X>` and all the elements
-of the initializer list can be implicitly converted to `X`, the implicit
-conversion sequence is the worst conversion necessary to convert an
-element of the list to `X`, or if the initializer list has no elements,
-the identity conversion. This conversion can be a user-defined
 conversion even in the context of a call to an initializer-list
 constructor.
 ``` cpp
 void f(std::initializer_list<int>);
 f( {} );                // OK: f(initializer_list<int>) identity conversion
 f( {1,2,3} );           // OK: f(initializer_list<int>) identity conversion
 f( {'a','b'} );         // OK: f(initializer_list<int>) integral promotion
@@ -1003,27 +1217,38 @@ g({ "foo", "bar" });        // OK, uses #3
 typedef int IA[3];
 void h(const IA&);
 h({ 1, 2, 3 });         // OK: identity conversion
 ```
-Otherwise, if the parameter type is “array of `N` `X`”[^12], if the
-initializer list has exactly `N` elements or if it has fewer than `N`
-elements and `X` is default-constructible, and if all the elements of
-the initializer list can be implicitly converted to `X`, the implicit
-conversion sequence is the worst conversion necessary to convert an
-element of the list to `X`.
 Otherwise, if the parameter is a non-aggregate class `X` and overload
-resolution per  [[over.match.list]] chooses a single best constructor of
-`X` to perform the initialization of an object of type `X` from the
-argument initializer list, the implicit conversion sequence is a
-user-defined conversion sequence with the second standard conversion
-sequence an identity conversion. If multiple constructors are viable but
-none is better than the others, the implicit conversion sequence is the
-ambiguous conversion sequence. User-defined conversions are allowed for
-conversion of the initializer list elements to the constructor parameter
-types except as noted in  [[over.best.ics]].
 ``` cpp
 struct A {
   A(std::initializer_list<int>);
 };
@@ -1051,16 +1276,20 @@ struct D {
 };
 void i(D);
 i({ {1,2}, {"bar"} });  // OK: i(D(A(std::initializer_list<int>{1,2\), C(std::string("bar"))))}
 ```
 Otherwise, if the parameter has an aggregate type which can be
 initialized from the initializer list according to the rules for
 aggregate initialization ([[dcl.init.aggr]]), the implicit conversion
 sequence is a user-defined conversion sequence with the second standard
 conversion sequence an identity conversion.
 ``` cpp
 struct A {
   int m1;
   double m2;
 };
@@ -1068,13 +1297,18 @@ struct A {
 void f(A);
 f( {'a', 'b'} );        // OK: f(A(int,double)) user-defined conversion
 f( {1.0} );             // error: narrowing
 ```
-Otherwise, if the parameter is a reference, see  [[over.ics.ref]]. The
-rules in this section will apply for initializing the underlying
-temporary for the reference.
 ``` cpp
 struct A {
   int m1;
   double m2;
@@ -1086,33 +1320,41 @@ f( {1.0} );                 // error: narrowing
 void g(const double &);
 g({1});                 // same conversion as int to double
 ```
 Otherwise, if the parameter type is not a class:
-- if the initializer list has one element, the implicit conversion
- sequence is the one required to convert the element to the parameter
-  type;
   ``` cpp
   void f(int);
   f( {'a'} );             // OK: same conversion as char to int
   f( {1.0} );             // error: narrowing
   ```
 - if the initializer list has no elements, the implicit conversion
   sequence is the identity conversion.
   ``` cpp
   void f(int);
   f( { } );               // OK: identity conversion
   ```
 In all cases other than those enumerated above, no conversion is
 possible.
 #### Ranking implicit conversion sequences <a id="over.ics.rank">[[over.ics.rank]]</a>
-[[over.ics.rank]] defines a partial ordering of implicit conversion
 sequences based on the relationships *better conversion sequence* and
 *better conversion*. If an implicit conversion sequence S1 is defined by
 these rules to be a better conversion sequence than S2, then it is also
 the case that S2 is a *worse conversion sequence* than S1. If conversion
 sequence S1 is neither better than nor worse than conversion sequence
@@ -1129,10 +1371,31 @@ defined in  [[over.best.ics]])
   [[over.ics.ellipsis]]).
 Two implicit conversion sequences of the same form are indistinguishable
 conversion sequences unless one of the following rules applies:
 - Standard conversion sequence `S1` is a better conversion sequence than
   standard conversion sequence `S2` if
   - `S1` is a proper subsequence of `S2` (comparing the conversion
     sequences in the canonical form defined by  [[over.ics.scs]],
     excluding any Lvalue Transformation; the identity conversion
@@ -1142,11 +1405,12 @@ conversion sequences unless one of the following rules applies:
     have the same rank and are distinguishable by the rules in the
     paragraph below, or, if not that,
   - `S1` and `S2` are reference bindings ([[dcl.init.ref]]) and neither
     refers to an implicit object parameter of a non-static member
     function declared without a *ref-qualifier*, and `S1` binds an
-    rvalue reference to an rvalue and `S2` binds an lvalue reference.
     ``` cpp
     int i;
     int f1();
     int&& f2();
     int g(const int&);
@@ -1168,41 +1432,47 @@ conversion sequences unless one of the following rules applies:
     a << 'c';                       // calls A::operator<<(int)
     A().p();                        // calls A::p()&&
     a.p();                          // calls A::p()&
     ```
     or, if not that,
   - `S1` and `S2` are reference bindings ([[dcl.init.ref]]) and `S1`
     binds an lvalue reference to a function lvalue and `S2` binds an
-    rvalue reference to a function lvalue.
     ``` cpp
     int f(void(&)());               // #1
     int f(void(&&)());              // #2
     void g();
     int i1 = f(g);                  // calls #1
     ```
     or, if not that,
   - `S1`
     and `S2` differ only in their qualification conversion and yield
     similar types `T1` and `T2` ([[conv.qual]]), respectively, and the
     cv-qualification signature of type `T1` is a proper subset of the
-    cv-qualification signature of type `T2`.
     ``` cpp
     int f(const volatile int *);
     int f(const int *);
     int i;
     int j = f(&i);                  // calls f(const int*)
     ```
     or, if not that,
   - `S1`
     and `S2` are reference bindings ([[dcl.init.ref]]), and the types
     to which the references refer are the same type except for top-level
     cv-qualifiers, and the type to which the reference initialized by
     `S2` refers is more cv-qualified than the type to which the
     reference initialized by `S1` refers.
     ``` cpp
     int f(const int &);
     int f(int &);
     int g(const int &);
     int g(int);
@@ -1218,31 +1488,30 @@ conversion sequences unless one of the following rules applies:
     void g(const X& a, X b) {
       a.f();                        // calls X::f() const
       b.f();                        // calls X::f()
     }
     ```
 - User-defined conversion sequence `U1` is a better conversion sequence
   than another user-defined conversion sequence `U2` if they contain the
   same user-defined conversion function or constructor or they
   initialize the same class in an aggregate initialization and in either
   case the second standard conversion sequence of `U1` is better than
   the second standard conversion sequence of `U2`.
   ``` cpp
   struct A {
     operator short();
   } a;
   int f(int);
   int f(float);
   int i = f(a);                   // calls f(int), because short → int is
                                   // better than short → float.
   ```
-- List-initialization sequence `L1` is a better conversion sequence than
- list-initialization sequence `L2` if
-  - `L1` converts to `std::initializer_list<X>` for some `X` and `L2`
-    does not, or, if not that,
-  - `L1` converts to type “array of `N1` `T`”, `L2` converts to type
-    “array of `N2` `T`”, and `N1` is smaller than `N2`.
 Standard conversion sequences are ordered by their ranks: an Exact Match
 is a better conversion than a Promotion, which is a better conversion
 than a Conversion. Two conversion sequences with the same rank are
 indistinguishable unless one of the following rules applies:
@@ -1258,19 +1527,22 @@ indistinguishable unless one of the following rules applies:
   of `B*` to `void*`.
 - If class `B` is derived directly or indirectly from class `A` and
   class `C` is derived directly or indirectly from `B`,
   - conversion of `C*` to `B*` is better than conversion of `C*` to
     `A*`,
     ``` cpp
     struct A {};
     struct B : public A {};
     struct C : public B {};
     C* pc;
     int f(A*);
     int f(B*);
     int i = f(pc);                  // calls f(B*)
     ```
   - binding of an expression of type `C` to a reference to type `B` is
     better than binding an expression of type `C` to a reference to type
     `A`,
   - conversion of `A::*` to `B::*` is better than conversion of `A::*`
     to `C::*`,
@@ -1282,11 +1554,11 @@ indistinguishable unless one of the following rules applies:
     `A`,
   - conversion of `B::*` to `C::*` is better than conversion of `A::*`
     to `C::*`, and
   - conversion of `B` to `A` is better than conversion of `C` to `A`.
-  Compared conversion sequences will have different source types only in
-  the context of comparing the second standard conversion sequence of an
-  initialization by user-defined conversion (see  [[over.match.best]]);
-  in all other contexts, the source types will be the same and the
-  target types will be different.

 call and a set of *candidate functions* that can be called based on the
 context of the call. The selection criteria for the best function are
 the number of arguments, how well the arguments match the
 parameter-type-list of the candidate function, how well (for non-static
 member functions) the object matches the implicit object parameter, and
+certain other properties of the candidate function.
+[*Note 1*: The function selected by overload resolution is not
+guaranteed to be appropriate for the context. Other restrictions, such
+as the accessibility of the function, can make its use in the calling
+context ill-formed. — *end note*]
 Overload resolution selects the function to call in seven distinct
 contexts within the language:
 - invocation of a function named in the function call syntax (
   conversion function, a reference-to-pointer-to-function conversion
   function, or a reference-to-function conversion function on a class
   object named in the function call syntax ([[over.call.object]]);
 - invocation of the operator referenced in an expression (
   [[over.match.oper]]);
+- invocation of a constructor for default- or direct-initialization (
+ [[dcl.init]]) of a class object ([[over.match.ctor]]);
 - invocation of a user-defined conversion for copy-initialization (
   [[dcl.init]]) of a class object ([[over.match.copy]]);
 - invocation of a conversion function for initialization of an object of
+  a non-class type from an expression of class type (
   [[over.match.conv]]); and
 - invocation of a conversion function for conversion to a glvalue or
   class prvalue to which a reference ([[dcl.init.ref]]) will be
   directly bound ([[over.match.ref]]).
 implied object argument, if present, is always the first argument.
 For non-static member functions, the type of the implicit object
 parameter is
+- “lvalue reference to cv `X`” for functions declared without a
   *ref-qualifier* or with the `&` *ref-qualifier*
+- “rvalue reference to cv `X`” for functions declared with the `&&`
   *ref-qualifier*
+where `X` is the class of which the function is a member and cv is the
+cv-qualification on the member function declaration.
+[*Example 1*: For a `const` member function of class `X`, the extra
+parameter is assumed to have type “reference to
+`const X`”. — *end example*]
+For conversion functions, the function is considered to be a member of
+the class of the implied object argument for the purpose of defining the
+type of the implicit object parameter. For non-conversion functions
+introduced by a *using-declaration* into a derived class, the function
+is considered to be a member of the derived class for the purpose of
+defining the type of the implicit object parameter. For static member
+functions, the implicit object parameter is considered to match any
+object (since if the function is selected, the object is discarded).
+[*Note 1*: No actual type is established for the implicit object
+parameter of a static member function, and no attempt will be made to
+determine a conversion sequence for that parameter (
+[[over.match.best]]). — *end note*]
 During overload resolution, the implied object argument is
 indistinguishable from other arguments. The implicit object parameter,
+however, retains its identity since no user-defined conversions can be
+applied to achieve a type match with it. For non-static member functions
+declared without a *ref-qualifier*, an additional rule applies:
+- even if the implicit object parameter is not const-qualified, an
   rvalue can be bound to the parameter as long as in all other respects
   the argument can be converted to the type of the implicit object
+  parameter. \[*Note 2*: The fact that such an argument is an rvalue
+ does not affect the ranking of implicit conversion sequences (
+  [[over.ics.rank]]). — *end note*]
 Because other than in list-initialization only one user-defined
 conversion is allowed in an implicit conversion sequence, special rules
 apply when selecting the best user-defined conversion (
 [[over.match.best]], [[over.best.ics]]).
+[*Example 2*:
 ``` cpp
 class T {
 public:
   T();
 };
   C(int);
 };
 T a = 1;            // ill-formed: T(C(1)) not tried
 ```
+— *end example*]
 In each case where a candidate is a function template, candidate
 function template specializations are generated using template argument
 deduction ([[temp.over]], [[temp.deduct]]). Those candidates are then
 handled as candidate functions in the usual way.[^2] A given name can
 refer to one or more function templates and also to a set of overloaded
 If the *postfix-expression* denotes the address of a set of overloaded
 functions and/or function templates, overload resolution is applied
 using that set as described above. If the function selected by overload
 resolution is a non-static member function, the program is ill-formed.
+[*Note 1*: The resolution of the address of an overload set in other
+contexts is described in [[over.over]]. — *end note*]
 ##### Call to named function <a id="over.call.func">[[over.call.func]]</a>
 Of interest in  [[over.call.func]] are only those function calls in
 which the *postfix-expression* ultimately contains a name that denotes
 construct `A->B` is generally equivalent to `(*A).B`, the rest of
 Clause  [[over]] assumes, without loss of generality, that all member
 function calls have been normalized to the form that uses an object and
 the `.` operator. Furthermore, Clause  [[over]] assumes that the
 *postfix-expression* that is the left operand of the `.` operator has
+type “cv `T`” where `T` denotes a class[^3]. Under this assumption, the
+*id-expression* in the call is looked up as a member function of `T`
 following the rules for looking up names in classes (
 [[class.member.lookup]]). The function declarations found by that lookup
 constitute the set of candidate functions. The argument list is the
 *expression-list* in the call augmented by the addition of the left
 operand of the `.` operator in the normalized member function call as
 of `T`, the call is ill-formed.
 ##### Call to object of class type <a id="over.call.object">[[over.call.object]]</a>
 If the *primary-expression* `E` in the function call syntax evaluates to
+a class object of type “cv `T`”, then the set of candidate functions
 includes at least the function call operators of `T`. The function call
 operators of `T` are obtained by ordinary lookup of the name
 `operator()` in the context of `(E).operator()`.
 In addition, for each non-explicit conversion function declared in `T`
 of the form
 ``` bnf
+'operator' conversion-type-id '( )' cv-qualifier ref-qualifierₒₚₜ noexcept-specifierₒₚₜ attribute-specifier-seqₒₚₜ ';'
 ```
 where *cv-qualifier* is the same cv-qualification as, or a greater
+cv-qualification than, cv, and where *conversion-type-id* denotes the
+type “pointer to function of (`P₁`, …, `Pₙ`) returning `R`”, or the type
+“reference to pointer to function of (`P₁`, …, `Pₙ`) returning `R`”, or
+the type “reference to function of (`P₁`, …, `Pₙ`) returning `R`”, a
 *surrogate call function* with the unique name *call-function* and
 having the form
 ``` bnf
+'R' call-function '(' conversion-type-id \ %
+'F, P₁ a₁, …, Pₙ aₙ)' '{ return F (a₁, …, aₙ); }'
 ```
 is also considered as a candidate function. Similarly, surrogate call
 functions are added to the set of candidate functions for each
 non-explicit conversion function declared in a base class of `T`
 function cannot be called (e.g., because of an ambiguity), the program
 is ill-formed.
 The argument list submitted to overload resolution consists of the
 argument expressions present in the function call syntax preceded by the
+implied object argument `(E)`.
+[*Note 2*: When comparing the call against the function call operators,
+the implied object argument is compared against the implicit object
+parameter of the function call operator. When comparing the call against
+a surrogate call function, the implied object argument is compared
+against the first parameter of the surrogate call function. The
+conversion function from which the surrogate call function was derived
+will be used in the conversion sequence for that parameter since it
+converts the implied object argument to the appropriate function pointer
+or reference required by that first parameter. — *end note*]
+[*Example 1*:
 ``` cpp
 int f1(int);
 int f2(float);
 typedef int (*fp1)(int);
 typedef int (*fp2)(float);
 struct A {
   operator fp1() { return f1; }
   operator fp2() { return f2; }
 } a;
+int i = a(1); // calls f1 via pointer returned from conversion function
 ```
+— *end example*]
 #### Operators in expressions <a id="over.match.oper">[[over.match.oper]]</a>
 If no operand of an operator in an expression has a type that is a class
 or an enumeration, the operator is assumed to be a built-in operator and
+interpreted according to Clause  [[expr]].
+[*Note 1*: Because `.`, `.*`, and `::` cannot be overloaded, these
+operators are always built-in operators interpreted according to Clause
+[[expr]]. `?:` cannot be overloaded, but the rules in this subclause are
+used to determine the conversions to be applied to the second and third
+operands when they have class or enumeration type (
+[[expr.cond]]). — *end note*]
+[*Example 1*:
 ``` cpp
 struct String {
   String (const String&);
   String (const char*);
   operator const char* ();
 };
 String operator + (const String&, const String&);
+void f() {
+ const char* p= "one" + "two";  // ill-formed because neither operand has class or enumeration type
+ int I = 1 + 1;                 // always evaluates to 2 even if class or enumeration types exist
+ // that would perform the operation.
 }
 ```
+— *end example*]
 If either operand has a type that is a class or an enumeration, a
 user-defined operator function might be declared that implements this
 operator or a user-defined conversion can be necessary to convert the
 operand to a type that is appropriate for a built-in operator. In this
 case, overload resolution is used to determine which operator function
 or built-in operator is to be invoked to implement the operator.
 Therefore, the operator notation is first transformed to the equivalent
 function-call notation as summarized in Table  [[tab:over.rel.op.func]]
 (where `@` denotes one of the operators covered in the specified
+subclause). However, the operands are sequenced in the order prescribed
+for the built-in operator (Clause  [[expr]]).
 **Table: Relationship between operator and function call notation** <a id="tab:over.rel.op.func">[tab:over.rel.op.func]</a>
 | Subclause    | Expression | As member function  | As non-member function |
+| ------------ | ---------- | ------------------- | ---------------------- |
+| (a)}         |
+| (a, b)}      |
+| [[over.ass]] | `a=b`      | `(a).operator= (b)` |                        |
+| [[over.sub]] | `a[b]`     | `(a).operator[](b)` |                        |
+| [[over.ref]] | `a->`      | `(a).operator->( )` |                        |
+| (a, 0)}      |
 For a unary operator `@` with an operand of a type whose cv-unqualified
 version is `T1`, and for a binary operator `@` with a left operand of a
 type whose cv-unqualified version is `T1` and a right operand of a type
   lookup of `operator@` in the context of the expression according to
   the usual rules for name lookup in unqualified function calls (
   [[basic.lookup.argdep]]) except that all member functions are ignored.
   However, if no operand has a class type, only those non-member
   functions in the lookup set that have a first parameter of type `T1`
+  or “reference to cv `T1`”, when `T1` is an enumeration type, or (if
+  there is a right operand) a second parameter of type `T2` or
+  “reference to cv `T2`”, when `T2` is an enumeration type, are
+  candidate functions.
 - For the operator `,`, the unary operator `&`, or the operator `->`,
   the built-in candidates set is empty. For all other operators, the
   built-in candidates include all of the candidate operator functions
   defined in  [[over.built]] that, compared to the given operator,
   - have the same operator name, and
 candidates. The argument list contains all of the operands of the
 operator. The best function from the set of candidate functions is
 selected according to  [[over.match.viable]] and
 [[over.match.best]].[^6]
+[*Example 2*:
 ``` cpp
 struct A {
   operator int();
 };
 A operator+(const A&, const A&);
   A a, b;
   a + b;                        // operator+(a, b) chosen over int(a) + int(b)
 }
 ```
+— *end example*]
 If a built-in candidate is selected by overload resolution, the operands
 of class type are converted to the types of the corresponding parameters
 of the selected operation function, except that the second standard
 conversion sequence of a user-defined conversion sequence (
 [[over.ics.user]]) is not applied. Then the operator is treated as the
 corresponding built-in operator and interpreted according to Clause
 [[expr]].
+[*Example 3*:
 ``` cpp
 struct X {
   operator double();
 };
 int *a = Y() + 100.0;           // error: pointer arithmetic requires integral operand
 int *b = Y() + X();             // error: pointer arithmetic requires integral operand
 ```
+— *end example*]
 The second operand of operator `->` is ignored in selecting an
 `operator->` function, and is not an argument when the `operator->`
 function is called. When `operator->` returns, the operator `->` is
 applied to the value returned, with the original second operand.[^7]
 If the operator is the operator `,`, the unary operator `&`, or the
 operator `->`, and there are no viable functions, then the operator is
 assumed to be the built-in operator and interpreted according to Clause
 [[expr]].
+[*Note 2*:
 The lookup rules for operators in expressions are different than the
 lookup rules for operator function names in a function call, as shown in
 the following example:
 ``` cpp
   operator+ (a,a);              // error: global operator hidden by member
   a + a;                        // OK: calls global operator+
 }
 ```
+— *end note*]
 #### Initialization by constructor <a id="over.match.ctor">[[over.match.ctor]]</a>
+When objects of class type are direct-initialized ([[dcl.init]]),
 copy-initialized from an expression of the same or a derived class
+type ([[dcl.init]]), or default-initialized ([[dcl.init]]), overload
+resolution selects the constructor. For direct-initialization or
+default-initialization that is not in the context of
+copy-initialization, the candidate functions are all the constructors of
+the class of the object being initialized. For copy-initialization, the
+candidate functions are all the converting constructors (
 [[class.conv.ctor]]) of that class. The argument list is the
 *expression-list* or *assignment-expression* of the *initializer*.
 #### Copy-initialization of class by user-defined conversion <a id="over.match.copy">[[over.match.copy]]</a>
 Under the conditions specified in  [[dcl.init]], as part of a
 copy-initialization of an object of class type, a user-defined
 conversion can be invoked to convert an initializer expression to the
 type of the object being initialized. Overload resolution is used to
+select the user-defined conversion to be invoked.
+[*Note 1*: The conversion performed for indirect binding to a reference
+to a possibly cv-qualified class type is determined in terms of a
+corresponding non-reference copy-initialization. — *end note*]
+Assuming that “*cv1* `T`” is the type of the object being initialized,
+with `T` a class type, the candidate functions are selected as follows:
 - The converting constructors ([[class.conv.ctor]]) of `T` are
   candidate functions.
+- When the type of the initializer expression is a class type “cv `S`”,
+  the non-explicit conversion functions of `S` and its base classes are
+  considered. When initializing a temporary to be bound to the first
+  parameter of a constructor where the parameter is of type “reference
+ to possibly cv-qualified `T`” and the constructor is called with a
+ single argument in the context of direct-initialization of an object
+ of type “*cv2* `T`”, explicit conversion functions are also
+ considered. Those that are not hidden within `S` and yield a type
+ whose cv-unqualified version is the same type as `T` or is a derived
+ class thereof are candidate functions. Conversion functions that
+ return “reference to `X`” return lvalues or xvalues, depending on the
+  type of reference, of type `X` and are therefore considered to yield
+ `X` for this process of selecting candidate functions.
 In both cases, the argument list has one argument, which is the
+initializer expression.
+[*Note 2*: This argument will be compared against the first parameter
+of the constructors and against the implicit object parameter of the
+conversion functions. — *end note*]
 #### Initialization by conversion function <a id="over.match.conv">[[over.match.conv]]</a>
 Under the conditions specified in  [[dcl.init]], as part of an
+initialization of an object of non-class type, a conversion function can
 be invoked to convert an initializer expression of class type to the
 type of the object being initialized. Overload resolution is used to
 select the conversion function to be invoked. Assuming that “*cv1* `T`”
+is the type of the object being initialized, and “cv `S`” is the type of
+the initializer expression, with `S` a class type, the candidate
 functions are selected as follows:
 - The conversion functions of `S` and its base classes are considered.
   Those non-explicit conversion functions that are not hidden within `S`
   and yield type `T` or a type that can be converted to type `T` via a
   return lvalues or xvalues, depending on the type of reference, of type
   “*cv2* `X`” and are therefore considered to yield `X` for this process
   of selecting candidate functions.
 The argument list has one argument, which is the initializer expression.
+[*Note 1*: This argument will be compared against the implicit object
+parameter of the conversion functions. — *end note*]
 #### Initialization by conversion function for direct reference binding <a id="over.match.ref">[[over.match.ref]]</a>
 Under the conditions specified in  [[dcl.init.ref]], a reference can be
 bound directly to a glvalue or class prvalue that is the result of
 applying a conversion function to an initializer expression. Overload
 resolution is used to select the conversion function to be invoked.
+Assuming that “reference to *cv1* `T`” is the type of the reference
+being initialized, and “cv `S`” is the type of the initializer
+expression, with `S` a class type, the candidate functions are selected
+as follows:
 - The conversion functions of `S` and its base classes are considered.
   Those non-explicit conversion functions that are not hidden within `S`
   and yield type “lvalue reference to *cv2* `T2`” (when initializing an
+  lvalue reference or an rvalue reference to function) or “*cv2* `T2`”
+ or “rvalue reference to *cv2* `T2`” (when initializing an rvalue
+ reference or an lvalue reference to function), where “*cv1* `T`” is
   reference-compatible ([[dcl.init.ref]]) with “*cv2* `T2`”, are
   candidate functions. For direct-initialization, those explicit
   conversion functions that are not hidden within `S` and yield type
   “lvalue reference to *cv2* `T2`” or “*cv2* `T2`” or “rvalue reference
+  to *cv2* `T2`”, respectively, where `T2` is the same type as `T` or
   can be converted to type `T` with a qualification conversion (
   [[conv.qual]]), are also candidate functions.
 The argument list has one argument, which is the initializer expression.
+[*Note 1*: This argument will be compared against the implicit object
+parameter of the conversion functions. — *end note*]
 #### Initialization by list-initialization <a id="over.match.list">[[over.match.list]]</a>
+When objects of non-aggregate class type `T` are list-initialized such
+that [[dcl.init.list]] specifies that overload resolution is performed
+according to the rules in this section, overload resolution selects the
+constructor in two phases:
 - Initially, the candidate functions are the initializer-list
   constructors ([[dcl.init.list]]) of the class `T` and the argument
   list consists of the initializer list as a single argument.
 - If no viable initializer-list constructor is found, overload
   the elements of the initializer list.
 If the initializer list has no elements and `T` has a default
 constructor, the first phase is omitted. In copy-list-initialization, if
 an `explicit` constructor is chosen, the initialization is ill-formed.
+[*Note 1*: This differs from other situations ([[over.match.ctor]],
 [[over.match.copy]]), where only converting constructors are considered
 for copy-initialization. This restriction only applies if this
+initialization is part of the final result of overload
+resolution. — *end note*]
+#### Class template argument deduction <a id="over.match.class.deduct">[[over.match.class.deduct]]</a>
+A set of functions and function templates is formed comprising:
+- For each constructor of the primary class template designated by the
+  *template-name*, if the template is defined, a function template with
+  the following properties:
+  - The template parameters are the template parameters of the class
+    template followed by the template parameters (including default
+    template arguments) of the constructor, if any.
+  - The types of the function parameters are those of the constructor.
+  - The return type is the class template specialization designated by
+    the *template-name* and template arguments corresponding to the
+    template parameters obtained from the class template.
+- If the primary class template `C` is not defined or does not declare
+  any constructors, an additional function template derived as above
+  from a hypothetical constructor `C()`.
+- An additional function template derived as above from a hypothetical
+  constructor `C(C)`, called the *copy deduction candidate*.
+- For each *deduction-guide*, a function or function template with the
+  following properties:
+  - The template parameters, if any, and function parameters are those
+    of the *deduction-guide*.
+  - The return type is the *simple-template-id* of the
+    *deduction-guide*.
+Initialization and overload resolution are performed as described in
+[[dcl.init]] and [[over.match.ctor]], [[over.match.copy]], or
+[[over.match.list]] (as appropriate for the type of initialization
+performed) for an object of a hypothetical class type, where the
+selected functions and function templates are considered to be the
+constructors of that class type for the purpose of forming an overload
+set, and the initializer is provided by the context in which class
+template argument deduction was performed. Each such notional
+constructor is considered to be explicit if the function or function
+template was generated from a constructor or *deduction-guide* that was
+declared `explicit`. All such notional constructors are considered to be
+public members of the hypothetical class type.
+[*Example 1*:
+``` cpp
+template <class T> struct A {
+  explicit A(const T&, ...) noexcept;  // #1
+  A(T&&, ...);                         // #2
+};
+int i;
+A a1 = { i, i };    // error: explicit constructor #1 selected in copy-list-initialization during deduction,
+                    // cannot deduce from non-forwarding rvalue reference in #2
+A a2{i, i};         // OK, #1 deduces to A<int> and also initializes
+A a3{0, i};         // OK, #2 deduces to A<int> and also initializes
+A a4 = {0, i};      // OK, #2 deduces to A<int> and also initializes
+template <class T> A(const T&, const T&) -> A<T&>;  // #3
+template <class T> explicit A(T&&, T&&) -> A<T>;    // #4
+A a5 = {0, 1};      // error: explicit deduction guide #4 selected in copy-list-initialization during deduction
+A a6{0,1};          // OK, #4 deduces to A<int> and #2 initializes
+A a7 = {0, i};      // error: #3 deduces to A<int&>, #1 and #2 declare same constructor
+A a8{0,i};          // error: #3 deduces to A<int&>, #1 and #2 declare same constructor
+template <class T> struct B {
+  template <class U> using TA = T;
+  template <class U> B(U, TA<U>);
+};
+B b{(int*)0, (char*)0};         // OK, deduces B<char*>
+```
+— *end example*]
 ### Viable functions <a id="over.match.viable">[[over.match.viable]]</a>
 From the set of candidate functions constructed for a given context (
 [[over.match.funcs]]), a set of viable functions is chosen, from which
 ### Best viable function <a id="over.match.best">[[over.match.best]]</a>
 Define ICS*i*(`F`) as follows:
+- If `F` is a static member function, ICS*1*(`F`) is defined such that
   ICS*1*(`F`) is neither better nor worse than ICS*1*(`G`) for any
   function `G`, and, symmetrically, ICS*1*(`G`) is neither better nor
+  worse than ICS*1*(`F`);[^9] otherwise,
 - let ICS*i*(`F`) denote the implicit conversion sequence that converts
   the *i*-th argument in the list to the type of the *i*-th parameter of
   viable function `F`. [[over.best.ics]] defines the implicit conversion
   sequences and [[over.ics.rank]] defines what it means for one implicit
   conversion sequence to be a better conversion sequence or worse
 - the context is an initialization by user-defined conversion (see
   [[dcl.init]], [[over.match.conv]], and  [[over.match.ref]]) and the
   standard conversion sequence from the return type of `F1` to the
   destination type (i.e., the type of the entity being initialized) is a
   better conversion sequence than the standard conversion sequence from
+  the return type of `F2` to the destination type
+  \[*Example 1*:
   ``` cpp
   struct A {
     A();
     operator int();
     operator double();
   } a;
+  int i = a; // a.operator int() followed by no conversion is better than
+ // a.operator double() followed by a conversion to int
   float x = a;        // ambiguous: both possibilities require conversions,
                       // and neither is better than the other
   ```
+  — *end example*]
   or, if not that,
 - the context is an initialization by conversion function for direct
   reference binding ([[over.match.ref]]) of a reference to function
   type, the return type of `F1` is the same kind of reference (i.e.
   lvalue or rvalue) as the reference being initialized, and the return
   type of `F2` is not
+  \[*Example 2*:
   ``` cpp
   template <class T> struct A {
     operator T&();    // #1
     operator T&&();   // #2
   };
   A<Fn> a;
   Fn& lf = a;         // calls #1
   Fn&& rf = a;        // calls #2
   ```
+  — *end example*]
   or, if not that,
 - `F1` is not a function template specialization and `F2` is a function
   template specialization, or, if not that,
 - `F1` and `F2` are function template specializations, and the function
   template for `F1` is more specialized than the template for `F2`
   according to the partial ordering rules described in
+  [[temp.func.order]], or, if not that,
+- `F1` is generated from a *deduction-guide* (
+  [[over.match.class.deduct]]) and `F2` is not, or, if not that,
+- `F1` is the copy deduction candidate ([[over.match.class.deduct]])
+  and `F2` is not, or, if not that,
+- `F1` is generated from a non-template constructor and `F2` is
+  generated from a constructor template.
+  \[*Example 3*:
+  ``` cpp
+  template <class T> struct A {
+    using value_type = T;
+    A(value_type);    // #1
+    A(const A&);      // #2
+    A(T, T, int);     // #3
+    template<class U>
+      A(int, T, U);   // #4
+    // #5 is the copy deduction candidate, A(A)
+  };
+  A x(1, 2, 3);       // uses #3, generated from a non-template constructor
+  template <class T>
+  A(T) -> A<T>;       // #6, less specialized than #5
+  A a(42);            // uses #6 to deduce A<int> and #1 to initialize
+  A b = a;            // uses #5 to deduce A<int> and #2 to initialize
+  template <class T>
+  A(A<T>) -> A<A<T>>; // #7, as specialized as #5
+  A b2 = a;           // uses #7 to deduce A<A<int>> and #1 to initialize
+  ```
+  — *end example*]
 If there is exactly one viable function that is a better function than
 all other viable functions, then it is the one selected by overload
+resolution; otherwise the call is ill-formed.[^10]
+[*Example 4*:
 ``` cpp
 void Fcn(const int*,  short);
 void Fcn(int*, int);
 int i;
 short s = 0;
 void f() {
+  Fcn(&i, s); // is ambiguous because &i → int* is better than &i → const int*
                     // but s → short is also better than s → int
+  Fcn(&i, 1L); // calls Fcn(int*, int), because &i → int* is better than &i → const int*
                     // and 1L → short and 1L → int are indistinguishable
+  Fcn(&i, 'c'); // calls Fcn(int*, int), because &i → int* is better than &i → const int*
                     // and c → int is better than c → short
 }
 ```
+— *end example*]
 If the best viable function resolves to a function for which multiple
 declarations were found, and if at least two of these declarations — or
 the declarations they refer to in the case of *using-declaration*s —
 specify a default argument that made the function viable, the program is
 ill-formed.
+[*Example 5*:
 ``` cpp
 namespace A {
   extern "C" void f(int = 5);
 }
 namespace B {
   f(3);             // OK, default argument was not used for viability
   f();              // Error: found default argument twice
 }
 ```
+— *end example*]
 #### Implicit conversion sequences <a id="over.best.ics">[[over.best.ics]]</a>
 An *implicit conversion sequence* is a sequence of conversions used to
 convert an argument in a function call to the type of the corresponding
 parameter of the function being called. The sequence of conversions is
 single expression ([[dcl.init]], [[dcl.init.ref]]).
 Implicit conversion sequences are concerned only with the type,
 cv-qualification, and value category of the argument and how these are
 converted to match the corresponding properties of the parameter. Other
+properties, such as the lifetime, storage class, alignment,
+accessibility of the argument, whether the argument is a bit-field, and
+whether a function is deleted ([[dcl.fct.def.delete]]), are ignored.
+So, although an implicit conversion sequence can be defined for a given
+argument-parameter pair, the conversion from the argument to the
+parameter might still be ill-formed in the final analysis.
 A well-formed implicit conversion sequence is one of the following
 forms:
 - a *standard conversion sequence* ([[over.ics.scs]]),
 -  [[over.match.ctor]], when the argument is the temporary in the second
   step of a class copy-initialization,
 -  [[over.match.copy]], [[over.match.conv]], or [[over.match.ref]] (in
   all cases), or
 - the second phase of [[over.match.list]] when the initializer list has
+  exactly one element that is itself an initializer list, and the target
+ is the first parameter of a constructor of class `X`, and the
+ conversion is to `X` or reference to cv `X`,
+user-defined conversion sequences are not considered.
+[*Note 1*: These rules prevent more than one user-defined conversion
+from being applied during overload resolution, thereby avoiding infinite
+recursion. — *end note*]
+[*Example 1*:
 ``` cpp
   struct Y { Y(int); };
   struct A { operator int(); };
   Y y1 = A();       // error: A::operator int() is not a candidate
   struct B { operator X(); };
   B b;
   X x({b});         // error: B::operator X() is not a candidate
 ```
+— *end example*]
 For the case where the parameter type is a reference, see
 [[over.ics.ref]].
 When the parameter type is not a reference, the implicit conversion
 sequence models a copy-initialization of the parameter from the argument
 expression. The implicit conversion sequence is the one required to
 convert the argument expression to a prvalue of the type of the
+parameter.
+[*Note 2*: When the parameter has a class type, this is a conceptual
 conversion defined for the purposes of Clause  [[over]]; the actual
 initialization is defined in terms of constructors and is not a
+conversion. — *end note*]
+Any difference in top-level cv-qualification is subsumed by the
+initialization itself and does not constitute a conversion.
+[*Example 2*: A parameter of type `A` can be initialized from an
+argument of type `const A`. The implicit conversion sequence for that
+case is the identity sequence; it contains no “conversion” from
+`const A` to `A`. — *end example*]
 When the parameter has a class type and the argument expression has the
 same type, the implicit conversion sequence is an identity conversion.
 When the parameter has a class type and the argument expression has a
 derived class type, the implicit conversion sequence is a
 derived-to-base Conversion from the derived class to the base class.
+[*Note 3*: There is no such standard conversion; this derived-to-base
+Conversion exists only in the description of implicit conversion
+sequences. — *end note*]
+A derived-to-base Conversion has Conversion rank ([[over.ics.scs]]).
 In all contexts, when converting to the implicit object parameter or
 when converting to the left operand of an assignment operation only
+standard conversion sequences are allowed.
 If no conversions are required to match an argument to a parameter type,
 the implicit conversion sequence is the standard conversion sequence
 consisting of the identity conversion ([[over.ics.scs]]).
 If no sequence of conversions can be found to convert an argument to a
+parameter type, an implicit conversion sequence cannot be formed.
 If several different sequences of conversions exist that each convert
 the argument to the parameter type, the implicit conversion sequence
 associated with the parameter is defined to be the unique conversion
 sequence designated the *ambiguous conversion sequence*. For the purpose
 of ranking implicit conversion sequences as described in
 [[over.ics.rank]], the ambiguous conversion sequence is treated as a
+user-defined conversion sequence that is indistinguishable from any
+other user-defined conversion sequence.
+[*Note 4*:
+This rule prevents a function from becoming non-viable because of an
+ambiguous conversion sequence for one of its parameters.
+[*Example 3*:
+``` cpp
+class B;
+class A { A (B&);};
+class B { operator A (); };
+class C { C (B&); };
+void f(A) { }
+void f(C) { }
+B b;
+f(b);               // ill-formed: ambiguous because there is a conversion b → C (via constructor)
+                    // and an (ambiguous) conversion b → A (via constructor or conversion function)
+void f(B) { }
+f(b);               // OK, unambiguous
+```
+— *end example*]
+— *end note*]
+If a function that uses the ambiguous conversion sequence is selected as
+the best viable function, the call will be ill-formed because the
+conversion of one of the arguments in the call is ambiguous.
 The three forms of implicit conversion sequences mentioned above are
 defined in the following subclauses.
 ##### Standard conversion sequences <a id="over.ics.scs">[[over.ics.scs]]</a>
 Table  [[tab:over.conversions]] summarizes the conversions defined in
 Clause  [[conv]] and partitions them into four disjoint categories:
 Lvalue Transformation, Qualification Adjustment, Promotion, and
+Conversion.
+[*Note 5*: These categories are orthogonal with respect to value
 category, cv-qualification, and data representation: the Lvalue
 Transformations do not change the cv-qualification or data
 representation of the type; the Qualification Adjustments do not change
 the value category or data representation of the type; and the
 Promotions and Conversions do not change the value category or
+cv-qualification of the type. — *end note*]
+[*Note 6*: As described in Clause  [[conv]], a standard conversion
+sequence is either the Identity conversion by itself (that is, no
+conversion) or consists of one to three conversions from the other four
+categories. If there are two or more conversions in the sequence, the
+conversions are applied in the canonical order: **Lvalue
 Transformation**, **Promotion** or **Conversion**, **Qualification
+Adjustment**. — *end note*]
 Each conversion in Table  [[tab:over.conversions]] also has an
 associated rank (Exact Match, Promotion, or Conversion). These are used
 to rank standard conversion sequences ([[over.ics.rank]]). The rank of
 a conversion sequence is determined by considering the rank of each
 an argument expression, the implicit conversion sequence is the identity
 conversion, unless the argument expression has a type that is a derived
 class of the parameter type, in which case the implicit conversion
 sequence is a derived-to-base Conversion ([[over.best.ics]]).
+[*Example 4*:
 ``` cpp
 struct A {};
 struct B : public A {} b;
 int f(A&);
 int f(B&);
+int i = f(b); // calls f(B&), an exact match, rather than f(A&), a conversion
 ```
+— *end example*]
 If the parameter binds directly to the result of applying a conversion
 function to the argument expression, the implicit conversion sequence is
 a user-defined conversion sequence ([[over.ics.user]]), with the second
 standard conversion sequence either an identity conversion or, if the
 conversion function returns an entity of a type that is a derived class
 of the parameter type, a derived-to-base Conversion.
 When a parameter of reference type is not bound directly to an argument
 expression, the conversion sequence is the one required to convert the
+argument expression to the referenced type according to
+[[over.best.ics]]. Conceptually, this conversion sequence corresponds to
+copy-initializing a temporary of the referenced type with the argument
+expression. Any difference in top-level cv-qualification is subsumed by
+the initialization itself and does not constitute a conversion.
 Except for an implicit object parameter, for which see
 [[over.match.funcs]], a standard conversion sequence cannot be formed if
 it requires binding an lvalue reference other than a reference to a
 non-volatile `const` type to an rvalue or binding an rvalue reference to
+an lvalue other than a function lvalue.
+[*Note 7*: This means, for example, that a candidate function cannot be
+a viable function if it has a non-`const` lvalue reference parameter
+(other than the implicit object parameter) and the corresponding
+argument would require a temporary to be created to initialize the
+lvalue reference (see  [[dcl.init.ref]]). — *end note*]
 Other restrictions on binding a reference to a particular argument that
 are not based on the types of the reference and the argument do not
+affect the formation of a standard conversion sequence, however.
+[*Example 5*: A function with an “lvalue reference to `int`” parameter
+can be a viable candidate even if the corresponding argument is an `int`
+bit-field. The formation of implicit conversion sequences treats the
+`int` bit-field as an `int` lvalue and finds an exact match with the
+parameter. If the function is selected by overload resolution, the call
+will nonetheless be ill-formed because of the prohibition on binding a
+non-`const` lvalue reference to a bit-field (
+[[dcl.init.ref]]). — *end example*]
 ##### List-initialization sequence <a id="over.ics.list">[[over.ics.list]]</a>
 When an argument is an initializer list ([[dcl.init.list]]), it is not
 an expression and special rules apply for converting it to a parameter
 type.
+If the parameter type is an aggregate class `X` and the initializer list
+has a single element of type cv `U`, where `U` is `X` or a class derived
+from `X`, the implicit conversion sequence is the one required to
+convert the element to the parameter type.
+Otherwise, if the parameter type is a character array [^11] and the
+initializer list has a single element that is an appropriately-typed
+string literal ([[dcl.init.string]]), the implicit conversion sequence
+is the identity conversion.
+Otherwise, if the parameter type is `std::initializer_list<X>` and all
+the elements of the initializer list can be implicitly converted to `X`,
+the implicit conversion sequence is the worst conversion necessary to
+convert an element of the list to `X`, or if the initializer list has no
+elements, the identity conversion. This conversion can be a user-defined
 conversion even in the context of a call to an initializer-list
 constructor.
+[*Example 6*:
 ``` cpp
 void f(std::initializer_list<int>);
 f( {} );                // OK: f(initializer_list<int>) identity conversion
 f( {1,2,3} );           // OK: f(initializer_list<int>) identity conversion
 f( {'a','b'} );         // OK: f(initializer_list<int>) integral promotion
 typedef int IA[3];
 void h(const IA&);
 h({ 1, 2, 3 });         // OK: identity conversion
 ```
+— *end example*]
+Otherwise, if the parameter type is “array of `N` `X`”, if there exists
+an implicit conversion sequence for each element of the array from the
+corresponding element of the initializer list (or from `{}` if there is
+no such element), the implicit conversion sequence is the worst such
+implicit conversion sequence.
 Otherwise, if the parameter is a non-aggregate class `X` and overload
+resolution per  [[over.match.list]] chooses a single best constructor
+`C` of `X` to perform the initialization of an object of type `X` from
+the argument initializer list:
+- If `C` is not an initializer-list constructor and the initializer list
+  has a single element of type cv `U`, where `U` is `X` or a class
+  derived from `X`, the implicit conversion sequence has Exact Match
+  rank if `U` is `X`, or Conversion rank if `U` is derived from `X`.
+- Otherwise, the implicit conversion sequence is a user-defined
+  conversion sequence with the second standard conversion sequence an
+  identity conversion.
+If multiple constructors are viable but none is better than the others,
+the implicit conversion sequence is the ambiguous conversion sequence.
+User-defined conversions are allowed for conversion of the initializer
+list elements to the constructor parameter types except as noted in
+[[over.best.ics]].
+[*Example 7*:
 ``` cpp
 struct A {
   A(std::initializer_list<int>);
 };
 };
 void i(D);
 i({ {1,2}, {"bar"} });  // OK: i(D(A(std::initializer_list<int>{1,2\), C(std::string("bar"))))}
 ```
+— *end example*]
 Otherwise, if the parameter has an aggregate type which can be
 initialized from the initializer list according to the rules for
 aggregate initialization ([[dcl.init.aggr]]), the implicit conversion
 sequence is a user-defined conversion sequence with the second standard
 conversion sequence an identity conversion.
+[*Example 8*:
 ``` cpp
 struct A {
   int m1;
   double m2;
 };
 void f(A);
 f( {'a', 'b'} );        // OK: f(A(int,double)) user-defined conversion
 f( {1.0} );             // error: narrowing
 ```
+— *end example*]
+Otherwise, if the parameter is a reference, see  [[over.ics.ref]].
+[*Note 8*: The rules in this section will apply for initializing the
+underlying temporary for the reference. — *end note*]
+[*Example 9*:
 ``` cpp
 struct A {
   int m1;
   double m2;
 void g(const double &);
 g({1});                 // same conversion as int to double
 ```
+— *end example*]
 Otherwise, if the parameter type is not a class:
+- if the initializer list has one element that is not itself an
+ initializer list, the implicit conversion sequence is the one required
+ to convert the element to the parameter type;
+  \[*Example 10*:
   ``` cpp
   void f(int);
   f( {'a'} );             // OK: same conversion as char to int
   f( {1.0} );             // error: narrowing
   ```
+  — *end example*]
 - if the initializer list has no elements, the implicit conversion
   sequence is the identity conversion.
+  \[*Example 11*:
   ``` cpp
   void f(int);
   f( { } );               // OK: identity conversion
   ```
+  — *end example*]
 In all cases other than those enumerated above, no conversion is
 possible.
 #### Ranking implicit conversion sequences <a id="over.ics.rank">[[over.ics.rank]]</a>
+This subclause defines a partial ordering of implicit conversion
 sequences based on the relationships *better conversion sequence* and
 *better conversion*. If an implicit conversion sequence S1 is defined by
 these rules to be a better conversion sequence than S2, then it is also
 the case that S2 is a *worse conversion sequence* than S1. If conversion
 sequence S1 is neither better than nor worse than conversion sequence
   [[over.ics.ellipsis]]).
 Two implicit conversion sequences of the same form are indistinguishable
 conversion sequences unless one of the following rules applies:
+- List-initialization sequence `L1` is a better conversion sequence than
+  list-initialization sequence `L2` if
+  - `L1` converts to `std::initializer_list<X>` for some `X` and `L2`
+    does not, or, if not that,
+  - `L1` converts to type “array of `N1` `T`”, `L2` converts to type
+    “array of `N2` `T`”, and `N1` is smaller than `N2`,
+  even if one of the other rules in this paragraph would otherwise
+  apply.
+  \[*Example 1*:
+  ``` cpp
+    void f1(int);                                 // #1
+    void f1(std::initializer_list<long>);         // #2
+    void g1() { f1({42}); }                       // chooses #2
+    void f2(std::pair<const char*, const char*>); // #3
+    void f2(std::initializer_list<std::string>);  // #4
+    void g2() { f2({"foo","bar"}); }              // chooses #4
+  ```
+  — *end example*]
 - Standard conversion sequence `S1` is a better conversion sequence than
   standard conversion sequence `S2` if
   - `S1` is a proper subsequence of `S2` (comparing the conversion
     sequences in the canonical form defined by  [[over.ics.scs]],
     excluding any Lvalue Transformation; the identity conversion
     have the same rank and are distinguishable by the rules in the
     paragraph below, or, if not that,
   - `S1` and `S2` are reference bindings ([[dcl.init.ref]]) and neither
     refers to an implicit object parameter of a non-static member
     function declared without a *ref-qualifier*, and `S1` binds an
+    rvalue reference to an rvalue and `S2` binds an lvalue reference
+    \[*Example 2*:
     ``` cpp
     int i;
     int f1();
     int&& f2();
     int g(const int&);
     a << 'c';                       // calls A::operator<<(int)
     A().p();                        // calls A::p()&&
     a.p();                          // calls A::p()&
     ```
+    — *end example*]
     or, if not that,
   - `S1` and `S2` are reference bindings ([[dcl.init.ref]]) and `S1`
     binds an lvalue reference to a function lvalue and `S2` binds an
+    rvalue reference to a function lvalue
+    \[*Example 3*:
     ``` cpp
     int f(void(&)());               // #1
     int f(void(&&)());              // #2
     void g();
     int i1 = f(g);                  // calls #1
     ```
+    — *end example*]
     or, if not that,
   - `S1`
     and `S2` differ only in their qualification conversion and yield
     similar types `T1` and `T2` ([[conv.qual]]), respectively, and the
     cv-qualification signature of type `T1` is a proper subset of the
+    cv-qualification signature of type `T2`
+    \[*Example 4*:
     ``` cpp
     int f(const volatile int *);
     int f(const int *);
     int i;
     int j = f(&i);                  // calls f(const int*)
     ```
+    — *end example*]
     or, if not that,
   - `S1`
     and `S2` are reference bindings ([[dcl.init.ref]]), and the types
     to which the references refer are the same type except for top-level
     cv-qualifiers, and the type to which the reference initialized by
     `S2` refers is more cv-qualified than the type to which the
     reference initialized by `S1` refers.
+    \[*Example 5*:
     ``` cpp
     int f(const int &);
     int f(int &);
     int g(const int &);
     int g(int);
     void g(const X& a, X b) {
       a.f();                        // calls X::f() const
       b.f();                        // calls X::f()
     }
     ```
+    — *end example*]
 - User-defined conversion sequence `U1` is a better conversion sequence
   than another user-defined conversion sequence `U2` if they contain the
   same user-defined conversion function or constructor or they
   initialize the same class in an aggregate initialization and in either
   case the second standard conversion sequence of `U1` is better than
   the second standard conversion sequence of `U2`.
+  \[*Example 6*:
   ``` cpp
   struct A {
     operator short();
   } a;
   int f(int);
   int f(float);
   int i = f(a);                   // calls f(int), because short → int is
                                   // better than short → float.
   ```
+ — *end example*]
 Standard conversion sequences are ordered by their ranks: an Exact Match
 is a better conversion than a Promotion, which is a better conversion
 than a Conversion. Two conversion sequences with the same rank are
 indistinguishable unless one of the following rules applies:
   of `B*` to `void*`.
 - If class `B` is derived directly or indirectly from class `A` and
   class `C` is derived directly or indirectly from `B`,
   - conversion of `C*` to `B*` is better than conversion of `C*` to
     `A*`,
+    \[*Example 7*:
     ``` cpp
     struct A {};
     struct B : public A {};
     struct C : public B {};
     C* pc;
     int f(A*);
     int f(B*);
     int i = f(pc);                  // calls f(B*)
     ```
+    — *end example*]
   - binding of an expression of type `C` to a reference to type `B` is
     better than binding an expression of type `C` to a reference to type
     `A`,
   - conversion of `A::*` to `B::*` is better than conversion of `A::*`
     to `C::*`,
     `A`,
   - conversion of `B::*` to `C::*` is better than conversion of `A::*`
     to `C::*`, and
   - conversion of `B` to `A` is better than conversion of `C` to `A`.
+ \[*Note 1*: Compared conversion sequences will have different source
+ types only in the context of comparing the second standard conversion
+ sequence of an initialization by user-defined conversion (see
+ [[over.match.best]]); in all other contexts, the source types will be
+ the same and the target types will be different. — *end note*]

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