[expr.compound] - C++20 → C++23

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@@ -1,24 +1,26 @@
 ## Compound expressions <a id="expr.compound">[[expr.compound]]</a>
 ### Postfix expressions <a id="expr.post">[[expr.post]]</a>
 Postfix expressions group left-to-right.
 ``` bnf
 postfix-expression:
     primary-expression
-    postfix-expression '[' expr-or-braced-init-list ']'
     postfix-expression '(' expression-listₒₚₜ ')'
     simple-type-specifier '(' expression-listₒₚₜ ')'
     typename-specifier '(' expression-listₒₚₜ ')'
     simple-type-specifier braced-init-list
     typename-specifier braced-init-list
     postfix-expression '.' 'template'ₒₚₜ id-expression
     postfix-expression '->' 'template'ₒₚₜ id-expression
     postfix-expression '++'
-    postfix-expression '-{-}'
     dynamic_cast '<' type-id '>' '(' expression ')'
     static_cast '<' type-id '>' '(' expression ')'
     reinterpret_cast '<' type-id '>' '(' expression ')'
     const_cast '<' type-id '>' '(' expression ')'
     typeid '(' expression ')'
@@ -29,38 +31,43 @@ postfix-expression:
 expression-list:
     initializer-list
 ```
 [*Note 1*: The `>` token following the *type-id* in a `dynamic_cast`,
-`static_cast`, `reinterpret_cast`, or `const_cast` may be the product of
-replacing a `>{>}` token by two consecutive `>` tokens
 [[temp.names]]. — *end note*]
 #### Subscripting <a id="expr.sub">[[expr.sub]]</a>
-A postfix expression followed by an expression in square brackets is a
-postfix expression. One of the expressions shall be a glvalue of type
-“array of `T`” or a prvalue of type “pointer to `T`” and the other shall
-be a prvalue of unscoped enumeration or integral type. The result is of
-type “`T`”. The type “`T`” shall be a completely-defined object
-type.[^11] The expression `E1[E2]` is identical (by definition) to
-`*((E1)+(E2))`, except that in the case of an array operand, the result
-is an lvalue if that operand is an lvalue and an xvalue otherwise. The
-expression `E1` is sequenced before the expression `E2`.
-[*Note 1*: A comma expression [[expr.comma]] appearing as the
-*expr-or-braced-init-list* of a subscripting expression is deprecated;
-see [[depr.comma.subscript]]. — *end note*]
-[*Note 2*: Despite its asymmetric appearance, subscripting is a
 commutative operation except for sequencing. See  [[expr.unary]] and
 [[expr.add]] for details of `*` and `+` and  [[dcl.array]] for details
 of array types. — *end note*]
-A *braced-init-list* shall not be used with the built-in subscript
-operator.
 #### Function call <a id="expr.call">[[expr.call]]</a>
 A function call is a postfix expression followed by parentheses
 containing a possibly empty, comma-separated list of
 *initializer-clause*s which constitute the arguments to the function.
@@ -74,72 +81,69 @@ type. For a call to a non-member function or to a static member
 function, the postfix expression shall either be an lvalue that refers
 to a function (in which case the function-to-pointer standard conversion
 [[conv.func]] is suppressed on the postfix expression), or have function
 pointer type.
-For a call to a non-static member function, the postfix expression shall
-be an implicit ([[class.mfct.non-static]], [[class.static]]) or
-explicit class member access [[expr.ref]] whose *id-expression* is a
-function member name, or a pointer-to-member expression
-[[expr.mptr.oper]] selecting a function member; the call is as a member
-of the class object referred to by the object expression. In the case of
-an implicit class member access, the implied object is the one pointed
-to by `this`.
-[*Note 2*: A member function call of the form `f()` is interpreted as
-`(*this).f()` (see  [[class.mfct.non-static]]). — *end note*]
 If the selected function is non-virtual, or if the *id-expression* in
 the class member access expression is a *qualified-id*, that function is
 called. Otherwise, its final overrider [[class.virtual]] in the dynamic
 type of the object expression is called; such a call is referred to as a
 *virtual function call*.
-[*Note 3*: The dynamic type is the type of the object referred to by
 the current value of the object expression. [[class.cdtor]] describes
 the behavior of virtual function calls when the object expression refers
 to an object under construction or destruction. — *end note*]
-[*Note 4*: If a function or member function name is used, and name
 lookup [[basic.lookup]] does not find a declaration of that name, the
 program is ill-formed. No function is implicitly declared by such a
 call. — *end note*]
 If the *postfix-expression* names a destructor or pseudo-destructor
 [[expr.prim.id.dtor]], the type of the function call expression is
 `void`; otherwise, the type of the function call expression is the
 return type of the statically chosen function (i.e., ignoring the
 `virtual` keyword), even if the type of the function actually called is
-different. This return type shall be an object type, a reference type or
-cv `void`. If the *postfix-expression* names a pseudo-destructor (in
 which case the *postfix-expression* is a possibly-parenthesized class
 member access), the function call destroys the object of scalar type
-denoted by the object expression of the class member access (
-[[expr.ref]], [[basic.life]]).
-Calling a function through an expression whose function type is
-different from the function type of the called function’s definition
-results in undefined behavior.
-When a function is called, each parameter [[dcl.fct]] is initialized (
-[[dcl.init]], [[class.copy.ctor]]) with its corresponding argument. If
-there is no corresponding argument, the default argument for the
-parameter is used.
 [*Example 1*:
 ``` cpp
 template<typename ...T> int f(int n = 0, T ...t);
 int x = f<int>();               // error: no argument for second function parameter
 ```
 — *end example*]
-If the function is a non-static member function, the `this` parameter of
-the function [[class.this]] is initialized with a pointer to the object
-of the call, converted as if by an explicit type conversion
-[[expr.cast]].
 [*Note 5*: There is no access or ambiguity checking on this conversion;
 the access checking and disambiguation are done as part of the (possibly
 implicit) class member access operator. See  [[class.member.lookup]],
 [[class.access.base]], and  [[expr.ref]]. — *end note*]
@@ -157,14 +161,14 @@ enclosing full-expression. The initialization and destruction of each
 parameter occurs within the context of the calling function.
 [*Example 2*: The access of the constructor, conversion functions or
 destructor is checked at the point of call in the calling function. If a
 constructor or destructor for a function parameter throws an exception,
-the search for a handler starts in the scope of the calling function; in
-particular, if the function called has a *function-try-block*
-[[except.pre]] with a handler that could handle the exception, this
-handler is not considered. — *end example*]
 The *postfix-expression* is sequenced before each *expression* in the
 *expression-list* and any default argument. The initialization of a
 parameter, including every associated value computation and side effect,
 is indeterminately sequenced with respect to that of any other
@@ -220,14 +224,14 @@ statically chosen function.
 parameters, but these changes cannot affect the values of the arguments
 except where a parameter is of a reference type [[dcl.ref]]; if the
 reference is to a const-qualified type, `const_cast` is required to be
 used to cast away the constness in order to modify the argument’s value.
 Where a parameter is of `const` reference type a temporary object is
-introduced if needed ([[dcl.type]], [[lex.literal]], [[lex.string]],
-[[dcl.array]], [[class.temporary]]). In addition, it is possible to
-modify the values of non-constant objects through pointer
-parameters. — *end note*]
 A function can be declared to accept fewer arguments (by declaring
 default arguments [[dcl.fct.default]]) or more arguments (by using the
 ellipsis, `...`, or a function parameter pack [[dcl.fct]]) than the
 number of parameters in the function definition [[dcl.fct.def]].
@@ -277,73 +281,93 @@ A *simple-type-specifier* [[dcl.type.simple]] or *typename-specifier*
 by a *braced-init-list* (the initializer) constructs a value of the
 specified type given the initializer. If the type is a placeholder for a
 deduced class type, it is replaced by the return type of the function
 selected by overload resolution for class template deduction
 [[over.match.class.deduct]] for the remainder of this subclause.
 If the initializer is a parenthesized single expression, the type
 conversion expression is equivalent to the corresponding cast expression
 [[expr.cast]]. Otherwise, if the type is cv `void` and the initializer
 is `()` or `{}` (after pack expansion, if any), the expression is a
-prvalue of the specified type that performs no initialization.
-Otherwise, the expression is a prvalue of the specified type whose
-result object is direct-initialized [[dcl.init]] with the initializer.
-If the initializer is a parenthesized optional *expression-list*, the
-specified type shall not be an array type.
 #### Class member access <a id="expr.ref">[[expr.ref]]</a>
 A postfix expression followed by a dot `.` or an arrow `->`, optionally
-followed by the keyword `template` [[temp.names]], and then followed by
-an *id-expression*, is a postfix expression. The postfix expression
-before the dot or arrow is evaluated;[^12] the result of that
-evaluation, together with the *id-expression*, determines the result of
-the entire postfix expression.
 For the first option (dot) the first expression shall be a glvalue. For
 the second option (arrow) the first expression shall be a prvalue having
 pointer type. The expression `E1->E2` is converted to the equivalent
 form `(*(E1)).E2`; the remainder of [[expr.ref]] will address only the
 first option (dot).[^13]
 Abbreviating *postfix-expression*`.`*id-expression* as `E1.E2`, `E1` is
 called the *object expression*. If the object expression is of scalar
 type, `E2` shall name the pseudo-destructor of that same type (ignoring
-cv-qualifications) and `E1.E2` is an lvalue of type “function of ()
 returning `void`”.
-[*Note 1*: This value can only be used for a notional function call
 [[expr.prim.id.dtor]]. — *end note*]
 Otherwise, the object expression shall be of class type. The class type
 shall be complete unless the class member access appears in the
 definition of that class.
-[*Note 2*: If the class is incomplete, lookup in the complete class
-type is required to refer to the same declaration
-[[basic.scope.class]]. — *end note*]
-The *id-expression* shall name a member of the class or of one of its
-base classes.
-[*Note 3*: Because the name of a class is inserted in its class scope
-[[class]], the name of a class is also considered a nested member of
-that class. — *end note*]
-[*Note 4*:  [[basic.lookup.classref]] describes how names are looked up
 after the `.` and `->` operators. — *end note*]
 If `E2` is a bit-field, `E1.E2` is a bit-field. The type and value
 category of `E1.E2` are determined as follows. In the remainder of
 [[expr.ref]], *cq* represents either `const` or the absence of `const`
 and *vq* represents either `volatile` or the absence of `volatile`. *cv*
 represents an arbitrary set of cv-qualifiers, as defined in
 [[basic.type.qualifier]].
 If `E2` is declared to have type “reference to `T`”, then `E1.E2` is an
-lvalue; the type of `E1.E2` is `T`. Otherwise, one of the following
-rules applies.
 - If `E2` is a static data member and the type of `E2` is `T`, then
   `E1.E2` is an lvalue; the expression designates the named member of
   the class. The type of `E1.E2` is `T`.
 - If `E2` is a non-static data member and the type of `E1` is “*cq1 vq1*
@@ -356,33 +380,53 @@ rules applies.
   *cq12* stand for the “union” of *cq1* and *cq2*; that is, if *cq1* or
   *cq2* is `const`, then *cq12* is `const`. If `E2` is declared to be a
   `mutable` member, then the type of `E1.E2` is “*vq12* `T`”. If `E2` is
   not declared to be a `mutable` member, then the type of `E1.E2` is
   “*cq12* *vq12* `T`”.
-- If `E2` is a (possibly overloaded) member function, function overload
- resolution [[over.match]] is used to select the function to which `E2`
- refers. The type of `E1.E2` is the type of `E2` and `E1.E2` refers to
- the function referred to by `E2`.
   - If `E2` refers to a static member function, `E1.E2` is an lvalue.
   - Otherwise (when `E2` refers to a non-static member function),
     `E1.E2` is a prvalue. The expression can be used only as the
     left-hand operand of a member function call [[class.mfct]].
     \[*Note 5*: Any redundant set of parentheses surrounding the
     expression is ignored [[expr.prim.paren]]. — *end note*]
 - If `E2` is a nested type, the expression `E1.E2` is ill-formed.
 - If `E2` is a member enumerator and the type of `E2` is `T`, the
-  expression `E1.E2` is a prvalue. The type of `E1.E2` is `T`.
-If `E2` is a non-static data member or a non-static member function, the
-program is ill-formed if the class of which `E2` is directly a member is
-an ambiguous base [[class.member.lookup]] of the naming class
-[[class.access.base]] of `E2`.
 [*Note 6*: The program is also ill-formed if the naming class is an
 ambiguous base of the class type of the object expression; see
 [[class.access.base]]. — *end note*]
 #### Increment and decrement <a id="expr.post.incr">[[expr.post.incr]]</a>
 The value of a postfix `++` expression is the value of its operand.
 [*Note 1*: The value obtained is a copy of the original
@@ -405,11 +449,11 @@ The result is a prvalue. The type of the result is the cv-unqualified
 version of the type of the operand. If the operand is a bit-field that
 cannot represent the incremented value, the resulting value of the
 bit-field is *implementation-defined*. See also  [[expr.add]] and
 [[expr.ass]].
-The operand of postfix `\dcr` is decremented analogously to the postfix
 `++` operator.
 [*Note 3*: For prefix increment and decrement, see
 [[expr.pre.incr]]. — *end note*]
@@ -435,13 +479,14 @@ If `T` is “pointer to *cv1* `B`” and `v` has type “pointer to *cv2* `D`”
 such that `B` is a base class of `D`, the result is a pointer to the
 unique `B` subobject of the `D` object pointed to by `v`, or a null
 pointer value if `v` is a null pointer value. Similarly, if `T` is
 “reference to *cv1* `B`” and `v` has type *cv2* `D` such that `B` is a
 base class of `D`, the result is the unique `B` subobject of the `D`
-object referred to by `v`.[^14] In both the pointer and reference cases,
-the program is ill-formed if `B` is an inaccessible or ambiguous base
-class of `D`.
 [*Example 1*:
 ``` cpp
 struct B { };
@@ -461,11 +506,11 @@ If `v` is a null pointer value, the result is a null pointer value.
 If `T` is “pointer to cv `void`”, then the result is a pointer to the
 most derived object pointed to by `v`. Otherwise, a runtime check is
 applied to see if the object pointed or referred to by `v` can be
 converted to the type pointed or referred to by `T`.
-If `C` is the class type to which `T` points or refers, the runtime
 check logically executes as follows:
 - If, in the most derived object pointed (referred) to by `v`, `v`
   points (refers) to a public base class subobject of a `C` object, and
   if only one object of type `C` is derived from the subobject pointed
@@ -519,40 +564,44 @@ destruction. — *end note*]
 The result of a `typeid` expression is an lvalue of static type `const`
 `std::type_info` [[type.info]] and dynamic type `const` `std::type_info`
 or `const` *name* where *name* is an *implementation-defined* class
 publicly derived from `std::type_info` which preserves the behavior
-described in  [[type.info]].[^15] The lifetime of the object referred to
-by the lvalue extends to the end of the program. Whether or not the
-destructor is called for the `std::type_info` object at the end of the
-program is unspecified.
 When `typeid` is applied to a glvalue whose type is a polymorphic class
 type [[class.virtual]], the result refers to a `std::type_info` object
 representing the type of the most derived object [[intro.object]] (that
 is, the dynamic type) to which the glvalue refers. If the glvalue is
-obtained by applying the unary `*` operator to a pointer[^16] and the
-pointer is a null pointer value [[basic.compound]], the `typeid`
 expression throws an exception [[except.throw]] of a type that would
 match a handler of type `std::bad_typeid` exception [[bad.typeid]].
 When `typeid` is applied to an expression other than a glvalue of a
 polymorphic class type, the result refers to a `std::type_info` object
 representing the static type of the expression. Lvalue-to-rvalue
 [[conv.lval]], array-to-pointer [[conv.array]], and function-to-pointer
 [[conv.func]] conversions are not applied to the expression. If the
 expression is a prvalue, the temporary materialization conversion
 [[conv.rval]] is applied. The expression is an unevaluated operand
-[[expr.prop]].
 When `typeid` is applied to a *type-id*, the result refers to a
 `std::type_info` object representing the type of the *type-id*. If the
 type of the *type-id* is a reference to a possibly cv-qualified type,
 the result of the `typeid` expression refers to a `std::type_info`
-object representing the cv-unqualified referenced type. If the type of
-the *type-id* is a class type or a reference to a class type, the class
-shall be completely-defined.
 [*Note 1*: The *type-id* cannot denote a function type with a
 *cv-qualifier-seq* or a *ref-qualifier* [[dcl.fct]]. — *end note*]
 If the type of the expression or *type-id* is a cv-qualified type, the
@@ -572,12 +621,14 @@ typeid(D)  == typeid(d2);       // yields true
 typeid(D)  == typeid(const D&); // yields true
 ```
 — *end example*]
-If the header `<typeinfo>` is not imported or included prior to a use of
-`typeid`, the program is ill-formed.
 [*Note 2*: Subclause [[class.cdtor]] describes the behavior of `typeid`
 applied to an object under construction or destruction. — *end note*]
 #### Static cast <a id="expr.static.cast">[[expr.static.cast]]</a>
@@ -613,19 +664,19 @@ B &br = d;
 static_cast<D&>(br);            // produces lvalue denoting the original d object
 ```
 — *end example*]
-An lvalue of type “*cv1* `T1`” can be cast to type “rvalue reference to
-*cv2* `T2`” if “*cv2* `T2`” is reference-compatible with “*cv1* `T1`”
-[[dcl.init.ref]]. If the value is not a bit-field, the result refers to
-the object or the specified base class subobject thereof; otherwise, the
-lvalue-to-rvalue conversion [[conv.lval]] is applied to the bit-field
-and the resulting prvalue is used as the *expression* of the
-`static_cast` for the remainder of this subclause. If `T2` is an
-inaccessible [[class.access]] or ambiguous [[class.member.lookup]] base
-class of `T1`, a program that necessitates such a cast is ill-formed.
 An expression E can be explicitly converted to a type `T` if there is an
 implicit conversion sequence [[over.best.ics]] from E to `T`, if
 overload resolution for a direct-initialization [[dcl.init]] of an
 object or reference of type `T` from E would find at least one viable
@@ -654,13 +705,16 @@ direct-initialization defines the type of the expression as
 Otherwise, the `static_cast` shall perform one of the conversions listed
 below. No other conversion shall be performed explicitly using a
 `static_cast`.
 Any expression can be explicitly converted to type cv `void`, in which
-case it becomes a discarded-value expression [[expr.prop]].
-[*Note 3*: However, if the value is in a temporary object
 [[class.temporary]], the destructor for that object is not executed
 until the usual time, and the value of the object is preserved for the
 purpose of executing the destructor. — *end note*]
 The inverse of any standard conversion sequence [[conv]] not containing
@@ -698,39 +752,48 @@ explicitly converted to a floating-point type; the result is the same as
 that of converting from the original value to the floating-point type.
 A value of integral or enumeration type can be explicitly converted to a
 complete enumeration type. If the enumeration type has a fixed
 underlying type, the value is first converted to that type by integral
-conversion, if necessary, and then to the enumeration type. If the
-enumeration type does not have a fixed underlying type, the value is
-unchanged if the original value is within the range of the enumeration
-values [[dcl.enum]], and otherwise, the behavior is undefined. A value
-of floating-point type can also be explicitly converted to an
-enumeration type. The resulting value is the same as converting the
-original value to the underlying type of the enumeration [[conv.fpint]],
-and subsequently to the enumeration type.
 A prvalue of type “pointer to *cv1* `B`”, where `B` is a class type, can
 be converted to a prvalue of type “pointer to *cv2* `D`”, where `D` is a
 complete class derived [[class.derived]] from `B`, if *cv2* is the same
 cv-qualification as, or greater cv-qualification than, *cv1*. If `B` is
 a virtual base class of `D` or a base class of a virtual base class of
 `D`, or if no valid standard conversion from “pointer to `D`” to
 “pointer to `B`” exists [[conv.ptr]], the program is ill-formed. The
 null pointer value [[basic.compound]] is converted to the null pointer
 value of the destination type. If the prvalue of type “pointer to *cv1*
-`B`” points to a `B` that is actually a subobject of an object of type
-`D`, the resulting pointer points to the enclosing object of type `D`.
-Otherwise, the behavior is undefined.
 A prvalue of type “pointer to member of `D` of type *cv1* `T`” can be
 converted to a prvalue of type “pointer to member of `B` of type *cv2*
 `T`”, where `D` is a complete class type and `B` is a base class
 [[class.derived]] of `D`, if *cv2* is the same cv-qualification as, or
 greater cv-qualification than, *cv1*.
-[*Note 4*: Function types (including those used in
 pointer-to-member-function types) are never cv-qualified
 [[dcl.fct]]. — *end note*]
 If no valid standard conversion from “pointer to member of `B` of type
 `T`” to “pointer to member of `D` of type `T`” exists [[conv.mem]], the
@@ -739,11 +802,11 @@ converted to the null member pointer value of the destination type. If
 class `B` contains the original member, or is a base or derived class of
 the class containing the original member, the resulting pointer to
 member points to the original member. Otherwise, the behavior is
 undefined.
-[*Note 5*: Although class `B` need not contain the original member, the
 dynamic type of the object with which indirection through the pointer to
 member is performed must contain the original member; see
 [[expr.mptr.oper]]. — *end note*]
 A prvalue of type “pointer to *cv1* `void`” can be converted to a
@@ -751,14 +814,13 @@ prvalue of type “pointer to *cv2* `T`”, where `T` is an object type and
 *cv2* is the same cv-qualification as, or greater cv-qualification than,
 *cv1*. If the original pointer value represents the address `A` of a
 byte in memory and `A` does not satisfy the alignment requirement of
 `T`, then the resulting pointer value is unspecified. Otherwise, if the
 original pointer value points to an object *a*, and there is an object
-*b* of type `T` (ignoring cv-qualification) that is
-pointer-interconvertible [[basic.compound]] with *a*, the result is a
-pointer to *b*. Otherwise, the pointer value is unchanged by the
-conversion.
 [*Example 3*:
 ``` cpp
 T* p1 = new T;
@@ -808,39 +870,37 @@ A value of integral type or enumeration type can be explicitly converted
 to a pointer. A pointer converted to an integer of sufficient size (if
 any such exists on the implementation) and back to the same pointer type
 will have its original value; mappings between pointers and integers are
 otherwise *implementation-defined*.
-[*Note 4*: Except as described in [[basic.stc.dynamic.safety]], the
-result of such a conversion will not be a safely-derived pointer
-value. — *end note*]
 A function pointer can be explicitly converted to a function pointer of
 a different type.
-[*Note 5*: The effect of calling a function through a pointer to a
 function type [[dcl.fct]] that is not the same as the type used in the
 definition of the function is undefined [[expr.call]]. — *end note*]
 Except that converting a prvalue of type “pointer to `T1`” to the type
 “pointer to `T2`” (where `T1` and `T2` are function types) and back to
 its original type yields the original pointer value, the result of such
 a pointer conversion is unspecified.
-[*Note 6*: See also  [[conv.ptr]] for more details of pointer
 conversions. — *end note*]
 An object pointer can be explicitly converted to an object pointer of a
-different type.[^17] When a prvalue `v` of object pointer type is
-converted to the object pointer type “pointer to cv `T`”, the result is
 `static_cast<cv T*>(static_cast<cv~void*>(v))`.
-[*Note 7*: Converting a prvalue of type “pointer to `T1`” to the type
-“pointer to `T2`” (where `T1` and `T2` are object types and where the
-alignment requirements of `T2` are no stricter than those of `T1`) and
-back to its original type yields the original pointer
-value. — *end note*]
 Converting a function pointer to an object pointer type or vice versa is
 conditionally-supported. The meaning of such a conversion is
 *implementation-defined*, except that if an implementation supports
 conversions in both directions, converting a prvalue of one type to the
@@ -848,21 +908,23 @@ other type and back, possibly with different cv-qualification, shall
 yield the original pointer value.
 The null pointer value [[basic.compound]] is converted to the null
 pointer value of the destination type.
-[*Note 8*: A null pointer constant of type `std::nullptr_t` cannot be
 converted to a pointer type, and a null pointer constant of integral
 type is not necessarily converted to a null pointer
 value. — *end note*]
 A prvalue of type “pointer to member of `X` of type `T1`” can be
 explicitly converted to a prvalue of a different type “pointer to member
 of `Y` of type `T2`” if `T1` and `T2` are both function types or both
-object types.[^18] The null member pointer value [[conv.mem]] is
-converted to the null member pointer value of the destination type. The
-result of this conversion is unspecified, except in the following cases:
 - Converting a prvalue of type “pointer to member function” to a
   different pointer-to-member-function type and back to its original
   type yields the original pointer-to-member value.
 - Converting a prvalue of type “pointer to data member of `X` of type
@@ -890,17 +952,17 @@ otherwise, the result is a prvalue and the lvalue-to-rvalue
 Conversions that can be performed explicitly using `const_cast` are
 listed below. No other conversion shall be performed explicitly using
 `const_cast`.
 [*Note 1*: Subject to the restrictions in this subclause, an expression
-may be cast to its own type using a `const_cast`
 operator. — *end note*]
 For two similar types `T1` and `T2` [[conv.qual]], a prvalue of type
 `T1` may be explicitly converted to the type `T2` using a `const_cast`
-if, considering the cv-decompositions of both types, each P¹ᵢ is the
-same as P²ᵢ for all i. The result of a `const_cast` refers to the
 original entity.
 [*Example 1*:
 ``` cpp
@@ -933,46 +995,56 @@ materialization conversion [[conv.rval]] otherwise.
 A null pointer value [[basic.compound]] is converted to the null pointer
 value of the destination type. The null member pointer value
 [[conv.mem]] is converted to the null member pointer value of the
 destination type.
-[*Note 2*: Depending on the type of the object, a write operation
-through the pointer, lvalue or pointer to data member resulting from a
-`const_cast` that casts away a const-qualifier[^20] may produce
-undefined behavior [[dcl.type.cv]]. — *end note*]
 A conversion from a type `T1` to a type `T2` *casts away constness* if
-`T1` and `T2` are different, there is a cv-decomposition [[conv.qual]]
-of `T1` yielding *n* such that `T2` has a cv-decomposition of the form
 and there is no qualification conversion that converts `T1` to
 Casting from an lvalue of type `T1` to an lvalue of type `T2` using an
 lvalue reference cast or casting from an expression of type `T1` to an
 xvalue of type `T2` using an rvalue reference cast casts away constness
 if a cast from a prvalue of type “pointer to `T1`” to the type “pointer
 to `T2`” casts away constness.
 [*Note 3*: Some conversions which involve only changes in
-cv-qualification cannot be done using `const_cast.` For instance,
 conversions between pointers to functions are not covered because such
 conversions lead to values whose use causes undefined behavior. For the
 same reasons, conversions between pointers to member functions, and in
 particular, the conversion from a pointer to a const member function to
 a pointer to a non-const member function, are not
 covered. — *end note*]
 ### Unary expressions <a id="expr.unary">[[expr.unary]]</a>
 Expressions with unary operators group right-to-left.
 ``` bnf
 unary-expression:
     postfix-expression
     unary-operator cast-expression
     '++' cast-expression
-    '-{-}' cast-expression
     await-expression
     sizeof unary-expression
     sizeof '(' type-id ')'
     sizeof '...' '(' identifier ')'
     alignof '(' type-id ')'
@@ -980,41 +1052,43 @@ unary-expression:
     new-expression
     delete-expression
 ```
 ``` bnf
 unary-operator: one of
     '* & + - ! ~'
 ```
 #### Unary operators <a id="expr.unary.op">[[expr.unary.op]]</a>
-The unary `*` operator performs *indirection*: the expression to which
-it is applied shall be a pointer to an object type, or a pointer to a
-function type and the result is an lvalue referring to the object or
-function to which the expression points. If the type of the expression
-is “pointer to `T`”, the type of the result is “`T`”.
 [*Note 1*:  Indirection through a pointer to an incomplete type (other
 than cv `void`) is valid. The lvalue thus obtained can be used in
 limited ways (to initialize a reference, for example); this lvalue must
 not be converted to a prvalue, see  [[conv.lval]]. — *end note*]
-The result of each of the following unary operators is a prvalue.
-The result of the unary `&` operator is a pointer to its operand.
 - If the operand is a *qualified-id* naming a non-static or variant
-  member `m` of some class `C` with type `T`, the result has type
-  “pointer to member of class `C` of type `T`” and is a prvalue
- designating `C::m`.
-- Otherwise, if the operand is an lvalue of type `T`, the resulting
- expression is a prvalue of type “pointer to `T`” whose result is a
- pointer to the designated object [[intro.memory]] or function.
-  \[*Note 2*: In particular, taking the address of a variable of type
- “cv `T`” yields a pointer of type “pointer to cv `T`”. — *end note*]
-- Otherwise, the program is ill-formed.
 [*Example 1*:
 ``` cpp
 struct A { int i; };
@@ -1047,44 +1121,53 @@ the *unqualified-id*’s class. — *end note*]
 If `&` is applied to an lvalue of incomplete class type and the complete
 type declares `operator&()`, it is unspecified whether the operator has
 the built-in meaning or the operator function is called. The operand of
 `&` shall not be a bit-field.
-[*Note 5*: The address of an overloaded function [[over]] can be taken
-only in a context that uniquely determines which version of the
-overloaded function is referred to (see  [[over.over]]). Since the
-context might determine whether the operand is a static or non-static
-member function, the context can also affect whether the expression has
-type “pointer to function” or “pointer to member
-function”. — *end note*]
 The operand of the unary `+` operator shall have arithmetic, unscoped
 enumeration, or pointer type and the result is the value of the
 argument. Integral promotion is performed on integral or enumeration
 operands. The type of the result is the type of the promoted operand.
 The operand of the unary `-` operator shall have arithmetic or unscoped
-enumeration type and the result is the negation of its operand. Integral
 promotion is performed on integral or enumeration operands. The negative
 of an unsigned quantity is computed by subtracting its value from 2ⁿ,
 where n is the number of bits in the promoted operand. The type of the
 result is the type of the promoted operand.
 The operand of the logical negation operator `!` is contextually
 converted to `bool` [[conv]]; its value is `true` if the converted
 operand is `false` and `false` otherwise. The type of the result is
 `bool`.
-The operand of `~` shall have integral or unscoped enumeration type; the
-result is the ones’ complement of its operand. Integral promotions are
-performed. The type of the result is the type of the promoted operand.
 There is an ambiguity in the grammar when `~` is followed by a
 *type-name* or *decltype-specifier*. The ambiguity is resolved by
-treating `~` as the unary complement operator rather than as the start
-of an *unqualified-id* naming a destructor.
-[*Note 6*: Because the grammar does not permit an operator to follow
 the `.`, `->`, or `::` tokens, a `~` followed by a *type-name* or
 *decltype-specifier* in a member access expression or *qualified-id* is
 unambiguously parsed as a destructor name. — *end note*]
 #### Increment and decrement <a id="expr.pre.incr">[[expr.pre.incr]]</a>
@@ -1098,12 +1181,12 @@ operand; it is an lvalue, and it is a bit-field if the operand is a
 bit-field. The expression `++x` is equivalent to `x+=1`.
 [*Note 1*: See the discussions of addition [[expr.add]] and assignment
 operators [[expr.ass]] for information on conversions. — *end note*]
-The operand of prefix `\dcr` is modified [[defns.access]] by subtracting
-`1`. The requirements on the operand of prefix `\dcr` and the properties
 of its result are otherwise the same as those of prefix `++`.
 [*Note 2*: For postfix increment and decrement, see
 [[expr.post.incr]]. — *end note*]
@@ -1119,30 +1202,30 @@ await-expression:
 ```
 An *await-expression* shall appear only in a potentially-evaluated
 expression within the *compound-statement* of a *function-body* outside
 of a *handler* [[except.pre]]. In a *declaration-statement* or in the
-*simple-declaration* (if any) of a *for-init-statement*, an
 *await-expression* shall appear only in an *initializer* of that
 *declaration-statement* or *simple-declaration*. An *await-expression*
 shall not appear in a default argument [[dcl.fct.default]]. An
-*await-expression* shall not appear in the initializer of a block-scope
 variable with static or thread storage duration. A context within a
 function where an *await-expression* can appear is called a *suspension
 context* of the function.
 Evaluation of an *await-expression* involves the following auxiliary
 types, expressions, and objects:
 - *p* is an lvalue naming the promise object [[dcl.fct.def.coroutine]]
   of the enclosing coroutine and `P` is the type of that object.
-- *a* is the *cast-expression* if the *await-expression* was implicitly
- produced by a *yield-expression* [[expr.yield]], an initial suspend
- point, or a final suspend point [[dcl.fct.def.coroutine]]. Otherwise,
-  the *unqualified-id* `await_transform` is looked up within the scope
- of `P` by class member access lookup [[basic.lookup.classref]], and if
- this lookup finds at least one declaration, then *a* is
   *p*`.await_transform(`*cast-expression*`)`; otherwise, *a* is the
   *cast-expression*.
 - *o* is determined by enumerating the applicable `operator co_await`
   functions for an argument *a* [[over.match.oper]], and choosing the
   best one through overload resolution [[over.match]]. If overload
@@ -1170,25 +1253,31 @@ and the *await-ready* expression, then:
 - If the result of *await-ready* is `false`, the coroutine is considered
   suspended. Then:
   - If the type of *await-suspend* is `std::coroutine_handle<Z>`,
     *await-suspend*`.resume()` is evaluated. \[*Note 1*: This resumes
     the coroutine referred to by the result of *await-suspend*. Any
-    number of coroutines may be successively resumed in this fashion,
     eventually returning control flow to the current coroutine caller or
     resumer [[dcl.fct.def.coroutine]]. — *end note*]
   - Otherwise, if the type of *await-suspend* is `bool`, *await-suspend*
     is evaluated, and the coroutine is resumed if the result is `false`.
   - Otherwise, *await-suspend* is evaluated.
   If the evaluation of *await-suspend* exits via an exception, the
   exception is caught, the coroutine is resumed, and the exception is
-  immediately re-thrown [[except.throw]]. Otherwise, control flow
- returns to the current coroutine caller or resumer
- [[dcl.fct.def.coroutine]] without exiting any scopes [[stmt.jump]].
 - If the result of *await-ready* is `true`, or when the coroutine is
-  resumed, the *await-resume* expression is evaluated, and its result is
-  the result of the *await-expression*.
 [*Example 1*:
 ``` cpp
 template <typename T>
@@ -1215,11 +1304,11 @@ auto operator co_await(std::chrono::duration<Rep, Period> d) {
 using namespace std::chrono;
 my_future<int> h();
 my_future<void> g() {
-  std::cout << "just about go to sleep...\n";
   co_await 10ms;
   std::cout << "resumed\n";
   co_await h();
 }
@@ -1232,33 +1321,40 @@ int a[] = { co_await h() };     // error: await-expression outside of function s
 #### Sizeof <a id="expr.sizeof">[[expr.sizeof]]</a>
 The `sizeof` operator yields the number of bytes occupied by a
 non-potentially-overlapping object of the type of its operand. The
 operand is either an expression, which is an unevaluated operand
-[[expr.prop]], or a parenthesized *type-id*. The `sizeof` operator shall
-not be applied to an expression that has function or incomplete type, to
-the parenthesized name of such types, or to a glvalue that designates a
-bit-field. The result of `sizeof` applied to any of the narrow character
-types is `1`. The result of `sizeof` applied to any other fundamental
-type [[basic.fundamental]] is *implementation-defined*.
-[*Note 1*: In particular, `sizeof(bool)`, `sizeof(char16_t)`,
 `sizeof(char32_t)`, and `sizeof(wchar_t)` are
-implementation-defined.[^21] — *end note*]
 [*Note 2*: See  [[intro.memory]] for the definition of byte and
-[[basic.types]] for the definition of object
 representation. — *end note*]
 When applied to a reference type, the result is the size of the
 referenced type. When applied to a class, the result is the number of
 bytes in an object of that class including any padding required for
 placing objects of that type in an array. The result of applying
 `sizeof` to a potentially-overlapping subobject is the size of the type,
-not the size of the subobject. [^22] When applied to an array, the
-result is the total number of bytes in the array. This implies that the
-size of an array of n elements is n times the size of an element.
 The lvalue-to-rvalue [[conv.lval]], array-to-pointer [[conv.array]], and
 function-to-pointer [[conv.func]] standard conversions are not applied
 to the operand of `sizeof`. If the operand is a prvalue, the temporary
 materialization conversion [[conv.rval]] is applied.
@@ -1282,11 +1378,11 @@ struct count {
 The result of `sizeof` and `sizeof...` is a prvalue of type
 `std::size_t`.
 [*Note 3*: A `sizeof` expression is an integral constant expression
 [[expr.const]]. The type `std::size_t` is defined in the standard header
-`<cstddef>` ([[cstddef.syn]], [[support.types.layout]]). — *end note*]
 #### Alignof <a id="expr.alignof">[[expr.alignof]]</a>
 An `alignof` expression yields the alignment requirement of its operand
 type. The operand shall be a *type-id* representing a complete object
@@ -1294,21 +1390,21 @@ type, or an array thereof, or a reference to one of those types.
 The result is a prvalue of type `std::size_t`.
 [*Note 1*: An `alignof` expression is an integral constant expression
 [[expr.const]]. The type `std::size_t` is defined in the standard header
-`<cstddef>` ([[cstddef.syn]], [[support.types.layout]]). — *end note*]
 When `alignof` is applied to a reference type, the result is the
 alignment of the referenced type. When `alignof` is applied to an array
 type, the result is the alignment of the element type.
 #### `noexcept` operator <a id="expr.unary.noexcept">[[expr.unary.noexcept]]</a>
 The `noexcept` operator determines whether the evaluation of its
-operand, which is an unevaluated operand [[expr.prop]], can throw an
-exception [[except.throw]].
 ``` bnf
 noexcept-expression:
   noexcept '(' expression ')'
 ```
@@ -1324,17 +1420,17 @@ is potentially-throwing [[except.spec]].
 #### New <a id="expr.new">[[expr.new]]</a>
 The *new-expression* attempts to create an object of the *type-id*
 [[dcl.name]] or *new-type-id* to which it is applied. The type of that
 object is the *allocated type*. This type shall be a complete object
-type, but not an abstract class type or array thereof (
-[[intro.object]], [[basic.types]], [[class.abstract]]).
 [*Note 1*: Because references are not objects, references cannot be
 created by *new-expression*s. — *end note*]
-[*Note 2*: The *type-id* may be a cv-qualified type, in which case the
 object created by the *new-expression* has a cv-qualified
 type. — *end note*]
 ``` bnf
 new-expression:
@@ -1440,27 +1536,10 @@ returning `int`).
 — *end example*]
 — *end note*]
-Objects created by a *new-expression* have dynamic storage duration
-[[basic.stc.dynamic]].
-[*Note 5*:  The lifetime of such an object is not necessarily
-restricted to the scope in which it is created. — *end note*]
-When the allocated object is not an array, the result of the
-*new-expression* is a pointer to the object created.
-When the allocated object is an array (that is, the
-*noptr-new-declarator* syntax is used or the *new-type-id* or *type-id*
-denotes an array type), the *new-expression* yields a pointer to the
-initial element (if any) of the array.
-[*Note 6*: Both `new int` and `new int[10]` have type `int*` and the
-type of `new int[i][10]` is `int (*)[10]` — *end note*]
 The *attribute-specifier-seq* in a *noptr-new-declarator* appertains to
 the associated array type.
 Every *constant-expression* in a *noptr-new-declarator* shall be a
 converted constant expression [[expr.const]] of type `std::size_t` and
@@ -1472,12 +1551,12 @@ well-formed (because `n` is the *expression* of a
 `n` is not a constant expression). — *end example*]
 If the *type-id* or *new-type-id* denotes an array type of unknown bound
 [[dcl.array]], the *new-initializer* shall not be omitted; the allocated
 object is an array with `n` elements, where `n` is determined from the
-number of initial elements supplied in the *new-initializer* (
-[[dcl.init.aggr]], [[dcl.init.string]]).
 If the *expression* in a *noptr-new-declarator* is present, it is
 implicitly converted to `std::size_t`. The *expression* is erroneous if:
 - the expression is of non-class type and its value before converting to
@@ -1492,12 +1571,12 @@ implicitly converted to `std::size_t`. The *expression* is erroneous if:
   terminating `'\0'` in a *string-literal* [[lex.string]]) exceeds the
   number of elements to initialize.
 If the *expression* is erroneous after converting to `std::size_t`:
-- if the *expression* is a core constant expression, the program is
-  ill-formed;
 - otherwise, an allocation function is not called; instead
   - if the allocation function that would have been called has a
     non-throwing exception specification [[except.spec]], the value of
     the *new-expression* is the null pointer value of the required
     result type;
@@ -1506,10 +1585,26 @@ If the *expression* is erroneous after converting to `std::size_t`:
     `std::bad_array_new_length` [[new.badlength]].
 When the value of the *expression* is zero, the allocation function is
 called to allocate an array with no elements.
 A *new-expression* may obtain storage for the object by calling an
 allocation function [[basic.stc.dynamic.allocation]]. If the
 *new-expression* terminates by throwing an exception, it may release
 storage by calling a deallocation function
 [[basic.stc.dynamic.deallocation]]. If the allocated type is a non-array
@@ -1517,28 +1612,28 @@ type, the allocation function’s name is `operator new` and the
 deallocation function’s name is `operator delete`. If the allocated type
 is an array type, the allocation function’s name is `operator new[]` and
 the deallocation function’s name is `operator delete[]`.
 [*Note 7*: An implementation is required to provide default definitions
-for the global allocation functions ([[basic.stc.dynamic]],
-[[new.delete.single]], [[new.delete.array]]). A C++ program can provide
-alternative definitions of these functions [[replacement.functions]]
-and/or class-specific versions [[class.free]]. The set of allocation and
-deallocation functions that may be called by a *new-expression* may
-include functions that do not perform allocation or deallocation; for
-example, see [[new.delete.placement]]. — *end note*]
-If the *new-expression* begins with a unary `::` operator, the
-allocation function’s name is looked up in the global scope. Otherwise,
-if the allocated type is a class type `T` or array thereof, the
-allocation function’s name is looked up in the scope of `T`. If this
-lookup fails to find the name, or if the allocated type is not a class
-type, the allocation function’s name is looked up in the global scope.
 An implementation is allowed to omit a call to a replaceable global
-allocation function ([[new.delete.single]], [[new.delete.array]]). When
-it does so, the storage is instead provided by the implementation or
 provided by extending the allocation of another *new-expression*.
 During an evaluation of a constant expression, a call to an allocation
 function is always omitted.
@@ -1669,12 +1764,12 @@ from one invocation of `new` to another.
 — *end example*]
 [*Note 10*: Unless an allocation function has a non-throwing exception
 specification [[except.spec]], it indicates failure to allocate storage
-by throwing a `std::bad_alloc` exception (
-[[basic.stc.dynamic.allocation]], [[except]], [[bad.alloc]]); it returns
 a non-null pointer otherwise. If the allocation function has a
 non-throwing exception specification, it returns null to indicate
 failure to allocate storage and a non-null pointer
 otherwise. — *end note*]
@@ -1705,34 +1800,33 @@ evaluations of expressions in the *new-initializer*. Initialization of
 the allocated object is sequenced before the value computation of the
 *new-expression*.
 If the *new-expression* creates an object or an array of objects of
 class type, access and ambiguity control are done for the allocation
-function, the deallocation function [[class.free]], and the constructor
-[[class.ctor]] selected for the initialization (if any). If the
-*new-expression* creates an array of objects of class type, the
-destructor is potentially invoked [[class.dtor]].
-If any part of the object initialization described above[^24] terminates
-by throwing an exception and a suitable deallocation function can be
-found, the deallocation function is called to free the memory in which
-the object was being constructed, after which the exception continues to
-propagate in the context of the *new-expression*. If no unambiguous
-matching deallocation function can be found, propagating the exception
-does not cause the object’s memory to be freed.
 [*Note 13*: This is appropriate when the called allocation function
 does not allocate memory; otherwise, it is likely to result in a memory
 leak. — *end note*]
-If the *new-expression* begins with a unary `::` operator, the
-deallocation function’s name is looked up in the global scope.
-Otherwise, if the allocated type is a class type `T` or an array
-thereof, the deallocation function’s name is looked up in the scope of
-`T`. If this lookup fails to find the name, or if the allocated type is
-not a class type or array thereof, the deallocation function’s name is
-looked up in the global scope.
 A declaration of a placement deallocation function matches the
 declaration of a placement allocation function if it has the same number
 of parameters and, after parameter transformations [[dcl.fct]], all
 parameter types except the first are identical. If the lookup finds a
@@ -1783,26 +1877,32 @@ delete-expression:
 ```
 The first alternative is a *single-object delete expression*, and the
 second is an *array delete expression*. Whenever the `delete` keyword is
 immediately followed by empty square brackets, it shall be interpreted
-as the second alternative.[^25] The operand shall be of pointer to
-object type or of class type. If of class type, the operand is
-contextually implicitly converted [[conv]] to a pointer to object
-type.[^26] The *delete-expression*’s result has type `void`.
 If the operand has a class type, the operand is converted to a pointer
 type by calling the above-mentioned conversion function, and the
 converted operand is used in place of the original operand for the
 remainder of this subclause. In a single-object delete expression, the
 value of the operand of `delete` may be a null pointer value, a pointer
-to a non-array object created by a previous *new-expression*, or a
-pointer to a subobject [[intro.object]] representing a base class of
-such an object [[class.derived]]. If not, the behavior is undefined. In
-an array delete expression, the value of the operand of `delete` may be
-a null pointer value or a pointer value that resulted from a previous
-array *new-expression*.[^27] If not, the behavior is undefined.
 [*Note 1*: This means that the syntax of the *delete-expression* must
 match the type of the object allocated by `new`, not the syntax of the
 *new-expression*. — *end note*]
@@ -1810,17 +1910,17 @@ match the type of the object allocated by `new`, not the syntax of the
 *delete-expression*; it is not necessary to cast away the constness
 [[expr.const.cast]] of the pointer expression before it is used as the
 operand of the *delete-expression*. — *end note*]
 In a single-object delete expression, if the static type of the object
-to be deleted is different from its dynamic type and the selected
-deallocation function (see below) is not a destroying operator delete,
-the static type shall be a base class of the dynamic type of the object
-to be deleted and the static type shall have a virtual destructor or the
-behavior is undefined. In an array delete expression, if the dynamic
-type of the object to be deleted differs from its static type, the
-behavior is undefined.
 The *cast-expression* in a *delete-expression* shall be evaluated
 exactly once.
 If the object being deleted has incomplete class type at the point of
@@ -1861,61 +1961,78 @@ exception. — *end note*]
 If the value of the operand of the *delete-expression* is a null pointer
 value, it is unspecified whether a deallocation function will be called
 as described above.
-[*Note 4*: An implementation provides default definitions of the global
-deallocation functions `operator delete` for non-arrays
-[[new.delete.single]] and `operator delete[]` for arrays
-[[new.delete.array]]. A C++ program can provide alternative definitions
-of these functions [[replacement.functions]], and/or class-specific
-versions [[class.free]]. — *end note*]
-When the keyword `delete` in a *delete-expression* is preceded by the
-unary `::` operator, the deallocation function’s name is looked up in
-global scope. Otherwise, the lookup considers class-specific
-deallocation functions [[class.free]]. If no class-specific deallocation
-function is found, the deallocation function’s name is looked up in
-global scope.
-If deallocation function lookup finds more than one usual deallocation
-function, the function to be called is selected as follows:
 - If any of the deallocation functions is a destroying operator delete,
   all deallocation functions that are not destroying operator deletes
   are eliminated from further consideration.
 - If the type has new-extended alignment, a function with a parameter of
   type `std::align_val_t` is preferred; otherwise a function without
   such a parameter is preferred. If any preferred functions are found,
   all non-preferred functions are eliminated from further consideration.
 - If exactly one function remains, that function is selected and the
   selection process terminates.
-- If the deallocation functions have class scope, the one without a
-  parameter of type `std::size_t` is selected.
 - If the type is complete and if, for an array delete expression only,
   the operand is a pointer to a class type with a non-trivial destructor
-  or a (possibly multi-dimensional) array thereof, the function with a
   parameter of type `std::size_t` is selected.
 - Otherwise, it is unspecified whether a deallocation function with a
   parameter of type `std::size_t` is selected.
 For a single-object delete expression, the deleted object is the object
-denoted by the operand if its static type does not have a virtual
-destructor, and its most-derived object otherwise.
-[*Note 5*: If the deallocation function is not a destroying operator
 delete and the deleted object is not the most derived object in the
 former case, the behavior is undefined, as stated above. — *end note*]
 For an array delete expression, the deleted object is the array object.
 When a *delete-expression* is executed, the selected deallocation
 function shall be called with the address of the deleted object in a
 single-object delete expression, or the address of the deleted object
 suitably adjusted for the array allocation overhead [[expr.new]] in an
 array delete expression, as its first argument.
-[*Note 6*: Any cv-qualifiers in the type of the deleted object are
 ignored when forming this argument. — *end note*]
 If a destroying operator delete is used, an unspecified value is passed
 as the argument corresponding to the parameter of type
 `std::destroying_delete_t`. If a deallocation function with a parameter
@@ -1924,19 +2041,18 @@ deleted object is passed as the corresponding argument. If a
 deallocation function with a parameter of type `std::size_t` is used,
 the size of the deleted object in a single-object delete expression, or
 of the array plus allocation overhead in an array delete expression, is
 passed as the corresponding argument.
-[*Note 7*: If this results in a call to a replaceable deallocation
 function, and either the first argument was not the result of a prior
 call to a replaceable allocation function or the second or third
 argument was not the corresponding argument in said call, the behavior
-is undefined ([[new.delete.single]],
-[[new.delete.array]]). — *end note*]
 Access and ambiguity control are done for both the deallocation function
-and the destructor ([[class.dtor]], [[class.free]]).
 ### Explicit type conversion (cast notation) <a id="expr.cast">[[expr.cast]]</a>
 The result of the expression `(T)` *cast-expression* is of type `T`. The
 result is an lvalue if `T` is an lvalue reference type or an rvalue
@@ -2040,13 +2156,14 @@ type “pointer to member of `T`” to its first operand, which shall be of
 type “pointer to `U`” where `U` is either `T` or a class of which `T` is
 an unambiguous and accessible base class. The expression `E1->*E2` is
 converted into the equivalent form `(*(E1)).*E2`.
 Abbreviating *pm-expression*`.*`*cast-expression* as `E1.*E2`, `E1` is
-called the *object expression*. If the dynamic type of `E1` does not
-contain the member to which `E2` refers, the behavior is undefined.
-Otherwise, the expression `E1` is sequenced before the expression `E2`.
 The restrictions on cv-qualification, and the manner in which the
 cv-qualifiers of the operands are combined to produce the cv-qualifiers
 of the result, are the same as the rules for `E1.E2` given in
 [[expr.ref]].
@@ -2118,13 +2235,15 @@ The binary `*` operator indicates multiplication.
 The binary `/` operator yields the quotient, and the binary `%` operator
 yields the remainder from the division of the first expression by the
 second. If the second operand of `/` or `%` is zero the behavior is
 undefined. For integral operands the `/` operator yields the algebraic
-quotient with any fractional part discarded;[^28] if the quotient `a/b`
-is representable in the type of the result, `(a/b)*b + a%b` is equal to
-`a`; otherwise, the behavior of both `a/b` and `a%b` is undefined.
 ### Additive operators <a id="expr.add">[[expr.add]]</a>
 The additive operators `+` and `-` group left-to-right. The usual
 arithmetic conversions [[expr.arith.conv]] are performed for operands of
@@ -2165,30 +2284,41 @@ from an expression `P` of pointer type, the result has the type of `P`.
   (possibly-hypothetical) array element i + j of `x` if 0 ≤ i + j ≤ n
   and the expression `P - J` points to the (possibly-hypothetical) array
   element i - j of `x` if 0 ≤ i - j ≤ n.
 - Otherwise, the behavior is undefined.
 When two pointer expressions `P` and `Q` are subtracted, the type of the
 result is an *implementation-defined* signed integral type; this type
 shall be the same type that is defined as `std::ptrdiff_t` in the
 `<cstddef>` header [[support.types.layout]].
 - If `P` and `Q` both evaluate to null pointer values, the result is 0.
 - Otherwise, if `P` and `Q` point to, respectively, array elements i and
   j of the same array object `x`, the expression `P - Q` has the value
   i - j.
-- Otherwise, the behavior is undefined. \[*Note 1*: If the value i - j
   is not in the range of representable values of type `std::ptrdiff_t`,
   the behavior is undefined. — *end note*]
 For addition or subtraction, if the expressions `P` or `Q` have type
 “pointer to cv `T`”, where `T` and the array element type are not
 similar [[conv.qual]], the behavior is undefined.
-[*Note 2*: In particular, a pointer to a base class cannot be used for
-pointer arithmetic when the array contains objects of a derived class
-type. — *end note*]
 ### Shift operators <a id="expr.shift">[[expr.shift]]</a>
 The shift operators `<<` and `>>` group left-to-right.
@@ -2257,37 +2387,41 @@ Then:
 If both operands have the same enumeration type `E`, the operator yields
 the result of converting the operands to the underlying type of `E` and
 applying `<=>` to the converted operands.
-If at least one of the operands is of pointer type and the other operand
-is of pointer or array type, array-to-pointer conversions
 [[conv.array]], pointer conversions [[conv.ptr]], and qualification
 conversions [[conv.qual]] are performed on both operands to bring them
 to their composite pointer type [[expr.type]]. After the conversions,
 the operands shall have the same type.
 [*Note 1*: If both of the operands are arrays, array-to-pointer
 conversions [[conv.array]] are not applied. — *end note*]
-If the composite pointer type is an object pointer type, `p <=> q` is of
-type `std::strong_ordering`. If two pointer operands `p` and `q` compare
-equal [[expr.eq]], `p <=> q` yields `std::strong_ordering::equal`; if
-`p` and `q` compare unequal, `p <=> q` yields
   `std::strong_ordering::less` if `q` compares greater than `p` and
   `std::strong_ordering::greater` if `p` compares greater than `q`
-[[expr.rel]]. Otherwise, the result is unspecified.
 Otherwise, the program is ill-formed.
 The three comparison category types [[cmp.categories]] (the types
 `std::strong_ordering`, `std::weak_ordering`, and
-`std::partial_ordering`) are not predefined; if the header `<compare>`
-is not imported or included prior to a use of such a class type – even
-an implicit use in which the type is not named (e.g., via the `auto`
 specifier [[dcl.spec.auto]] in a defaulted three-way comparison
-[[class.spaceship]] or use of the built-in operator) – the program is
 ill-formed.
 ### Relational operators <a id="expr.rel">[[expr.rel]]</a>
 The relational operators group left-to-right.
@@ -2319,30 +2453,36 @@ operands of arithmetic or enumeration type. If both operands are
 pointers, pointer conversions [[conv.ptr]] and qualification conversions
 [[conv.qual]] are performed to bring them to their composite pointer
 type [[expr.type]]. After conversions, the operands shall have the same
 type.
-The result of comparing unequal pointers to objects [^30] is defined in
-terms of a partial order consistent with the following rules:
 - If two pointers point to different elements of the same array, or to
   subobjects thereof, the pointer to the element with the higher
   subscript is required to compare greater.
 - If two pointers point to different non-static data members of the same
   object, or to subobjects of such members, recursively, the pointer to
-  the later declared member is required to compare greater provided the
- two members have the same access control [[class.access]], neither
- member is a subobject of zero size, and their class is not a union.
 - Otherwise, neither pointer is required to compare greater than the
   other.
 If two operands `p` and `q` compare equal [[expr.eq]], `p<=q` and `p>=q`
 both yield `true` and `p<q` and `p>q` both yield `false`. Otherwise, if
-a pointer `p` compares greater than a pointer `q`, `p>=q`, `p>q`,
-`q<=p`, and `q<p` all yield `true` and `p<=q`, `p<q`, `q>=p`, and `q>p`
-all yield `false`. Otherwise, the result of each of the operators is
-unspecified.
 If both operands (after conversions) are of arithmetic or enumeration
 type, each of the operators shall yield `true` if the specified
 relationship is true and `false` if it is false.
@@ -2480,11 +2620,11 @@ exclusive-or-expression:
 The `^` operator groups left-to-right. The operands shall be of integral
 or unscoped enumeration type. The usual arithmetic conversions
 [[expr.arith.conv]] are performed. Given the coefficients `xᵢ` and `yᵢ`
 of the base-2 representation [[basic.fundamental]] of the converted
 operands `x` and `y`, the coefficient `rᵢ` of the base-2 representation
-of the result `r` is 1 if either (but not both) of `xᵢ` and `yᵢ` are 1,
 and 0 otherwise.
 [*Note 1*: The result is the bitwise exclusive function of the
 operands. — *end note*]
@@ -2499,11 +2639,11 @@ inclusive-or-expression:
 The `|` operator groups left-to-right. The operands shall be of integral
 or unscoped enumeration type. The usual arithmetic conversions
 [[expr.arith.conv]] are performed. Given the coefficients `xᵢ` and `yᵢ`
 of the base-2 representation [[basic.fundamental]] of the converted
 operands `x` and `y`, the coefficient `rᵢ` of the base-2 representation
-of the result `r` is 1 if at least one of `xᵢ` and `yᵢ` are 1, and 0
 otherwise.
 [*Note 1*: The result is the bitwise inclusive function of the
 operands. — *end note*]
@@ -2588,14 +2728,15 @@ that determination. — *end note*]
 Attempts are made to form an implicit conversion sequence from an
 operand expression `E1` of type `T1` to a target type related to the
 type `T2` of the operand expression `E2` as follows:
 - If `E2` is an lvalue, the target type is “lvalue reference to `T2`”,
- subject to the constraint that in the conversion the reference must
-  bind directly [[dcl.init.ref]] to a glvalue.
 - If `E2` is an xvalue, the target type is “rvalue reference to `T2`”,
- subject to the constraint that the reference must bind directly.
 - If `E2` is a prvalue or if neither of the conversion sequences above
   can be formed and at least one of the operands has (possibly
   cv-qualified) class type:
   - if `T1` and `T2` are the same class type (ignoring cv-qualification)
     and `T2` is at least as cv-qualified as `T1`, the target type is
@@ -2627,11 +2768,11 @@ and it is a bit-field if the second or the third operand is a bit-field,
 or if both are bit-fields.
 Otherwise, the result is a prvalue. If the second and third operands do
 not have the same type, and either has (possibly cv-qualified) class
 type, overload resolution is used to determine the conversions (if any)
-to be applied to the operands ([[over.match.oper]], [[over.built]]). If
 the overload resolution fails, the program is ill-formed. Otherwise, the
 conversions thus determined are applied, and the converted operands are
 used in place of the original operands for the remainder of this
 subclause.
@@ -2671,11 +2812,11 @@ yield-expression:
 A *yield-expression* shall appear only within a suspension context of a
 function [[expr.await]]. Let *e* be the operand of the
 *yield-expression* and *p* be an lvalue naming the promise object of the
 enclosing coroutine [[dcl.fct.def.coroutine]], then the
 *yield-expression* is equivalent to the expression
-`co_await `*p*`.yield_value(`*e*`)`.
 [*Example 1*:
 ``` cpp
 template <typename T>
@@ -2692,14 +2833,14 @@ struct my_generator {
   iterator begin();
   iterator end();
 };
 my_generator<pair<int,int>> g1() {
-  for (int i = i; i < 10; ++i) co_yield {i,i};
 }
 my_generator<pair<int,int>> g2() {
-  for (int i = i; i < 10; ++i) co_yield make_pair(i,i);
 }
 auto f(int x = co_yield 5);     // error: yield-expression outside of function suspension context
 int a[] = { co_yield 1 };       // error: yield-expression outside of function suspension context
@@ -2732,12 +2873,12 @@ exception [[except.handle]]. The exception is reactivated with the
 existing exception object; no new exception object is created. The
 exception is no longer considered to be caught.
 [*Example 1*:
-Code that must be executed because of an exception, but cannot
-completely handle the exception itself, can be written like this:
 ``` cpp
 try {
   // ...
 } catch (...) {     // catch all exceptions
@@ -2754,17 +2895,18 @@ If no exception is presently being handled, evaluating a
 ### Assignment and compound assignment operators <a id="expr.ass">[[expr.ass]]</a>
 The assignment operator (`=`) and the compound assignment operators all
 group right-to-left. All require a modifiable lvalue as their left
-operand; their result is an lvalue referring to the left operand. The
-result in all cases is a bit-field if the left operand is a bit-field.
-In all cases, the assignment is sequenced after the value computation of
-the right and left operands, and before the value computation of the
-assignment expression. The right operand is sequenced before the left
-operand. With respect to an indeterminately-sequenced function call, the
-operation of a compound assignment is a single evaluation.
 [*Note 1*: Therefore, a function call cannot intervene between the
 lvalue-to-rvalue conversion and the side effect associated with any
 single compound assignment operator. — *end note*]
@@ -2790,42 +2932,44 @@ If the right operand is an expression, it is implicitly converted
 When the left operand of an assignment operator is a bit-field that
 cannot represent the value of the expression, the resulting value of the
 bit-field is *implementation-defined*.
-A simple assignment whose left operand is of a volatile-qualified type
-is deprecated [[depr.volatile.type]] unless the (possibly parenthesized)
-assignment is a discarded-value expression or an unevaluated operand.
 The behavior of an expression of the form `E1 op= E2` is equivalent to
-`E1 = E1 op E2` except that `E1` is evaluated only once. Such
-expressions are deprecated if `E1` has volatile-qualified type; see
-[[depr.volatile.type]]. For `+=` and `-=`, `E1` shall either have
-arithmetic type or be a pointer to a possibly cv-qualified
-completely-defined object type. In all other cases, `E1` shall have
-arithmetic type.
 If the value being stored in an object is read via another object that
 overlaps in any way the storage of the first object, then the overlap
 shall be exact and the two objects shall have the same type, otherwise
 the behavior is undefined.
-[*Note 2*: This restriction applies to the relationship between the
 left and right sides of the assignment operation; it is not a statement
-about how the target of the assignment may be aliased in general. See
 [[basic.lval]]. — *end note*]
 A *braced-init-list* may appear on the right-hand side of
 - an assignment to a scalar, in which case the initializer list shall
   have at most a single element. The meaning of `x = {v}`, where `T` is
   the scalar type of the expression `x`, is that of `x = T{v}`. The
   meaning of `x = {}` is `x = T{}`.
 - an assignment to an object of class type, in which case the
   initializer list is passed as the argument to the assignment operator
-  function selected by overload resolution ([[over.ass]],
-  [[over.match]]).
 [*Example 1*:
 ``` cpp
 complex<double> z;
@@ -2854,27 +2998,25 @@ left expression is sequenced before the right expression
 [[intro.execution]]. The type and value of the result are the type and
 value of the right operand; the result is of the same value category as
 its right operand, and is a bit-field if its right operand is a
 bit-field.
-In contexts where comma is given a special meaning,
-[*Example 1*: in lists of arguments to functions [[expr.call]] and
-lists of initializers [[dcl.init]] — *end example*]
-the comma operator as described in this subclause can appear only in
-parentheses.
-[*Example 2*:
 ``` cpp
 f(a, (t=3, t+2), c);
 ```
 has three arguments, the second of which has the value `5`.
 — *end example*]
-[*Note 1*: A comma expression appearing as the
-*expr-or-braced-init-list* of a subscripting expression [[expr.sub]] is
-deprecated; see [[depr.comma.subscript]]. — *end note*]

 ## Compound expressions <a id="expr.compound">[[expr.compound]]</a>
 ### Postfix expressions <a id="expr.post">[[expr.post]]</a>
+#### General <a id="expr.post.general">[[expr.post.general]]</a>
 Postfix expressions group left-to-right.
 ``` bnf
 postfix-expression:
     primary-expression
+    postfix-expression '[' expression-listₒₚₜ ']'
     postfix-expression '(' expression-listₒₚₜ ')'
     simple-type-specifier '(' expression-listₒₚₜ ')'
     typename-specifier '(' expression-listₒₚₜ ')'
     simple-type-specifier braced-init-list
     typename-specifier braced-init-list
     postfix-expression '.' 'template'ₒₚₜ id-expression
     postfix-expression '->' 'template'ₒₚₜ id-expression
     postfix-expression '++'
+    postfix-expression '--'
     dynamic_cast '<' type-id '>' '(' expression ')'
     static_cast '<' type-id '>' '(' expression ')'
     reinterpret_cast '<' type-id '>' '(' expression ')'
     const_cast '<' type-id '>' '(' expression ')'
     typeid '(' expression ')'
 expression-list:
     initializer-list
 ```
 [*Note 1*: The `>` token following the *type-id* in a `dynamic_cast`,
+`static_cast`, `reinterpret_cast`, or `const_cast` can be the product of
+replacing a `>>` token by two consecutive `>` tokens
 [[temp.names]]. — *end note*]
 #### Subscripting <a id="expr.sub">[[expr.sub]]</a>
+A *subscript expression* is a postfix expression followed by square
+brackets containing a possibly empty, comma-separated list of
+*initializer-clause*s that constitute the arguments to the subscript
+operator. The *postfix-expression* and the initialization of the object
+parameter of any applicable subscript operator function is sequenced
+before each expression in the *expression-list* and also before any
+default argument. The initialization of a non-object parameter of a
+subscript operator function `S` [[over.sub]], including every associated
+value computation and side effect, is indeterminately sequenced with
+respect to that of any other non-object parameter of `S`.
+With the built-in subscript operator, an *expression-list* shall be
+present, consisting of a single *assignment-expression*. One of the
+expressions shall be a glvalue of type “array of `T`” or a prvalue of
+type “pointer to `T`” and the other shall be a prvalue of unscoped
+enumeration or integral type. The result is of type “`T`”. The type
+“`T`” shall be a completely-defined object type.[^11]
+The expression `E1[E2]` is identical (by definition) to `*((E1)+(E2))`,
+except that in the case of an array operand, the result is an lvalue if
+that operand is an lvalue and an xvalue otherwise.
+[*Note 1*: Despite its asymmetric appearance, subscripting is a
 commutative operation except for sequencing. See  [[expr.unary]] and
 [[expr.add]] for details of `*` and `+` and  [[dcl.array]] for details
 of array types. — *end note*]
 #### Function call <a id="expr.call">[[expr.call]]</a>
 A function call is a postfix expression followed by parentheses
 containing a possibly empty, comma-separated list of
 *initializer-clause*s which constitute the arguments to the function.
 function, the postfix expression shall either be an lvalue that refers
 to a function (in which case the function-to-pointer standard conversion
 [[conv.func]] is suppressed on the postfix expression), or have function
 pointer type.
 If the selected function is non-virtual, or if the *id-expression* in
 the class member access expression is a *qualified-id*, that function is
 called. Otherwise, its final overrider [[class.virtual]] in the dynamic
 type of the object expression is called; such a call is referred to as a
 *virtual function call*.
+[*Note 2*: The dynamic type is the type of the object referred to by
 the current value of the object expression. [[class.cdtor]] describes
 the behavior of virtual function calls when the object expression refers
 to an object under construction or destruction. — *end note*]
+[*Note 3*: If a function or member function name is used, and name
 lookup [[basic.lookup]] does not find a declaration of that name, the
 program is ill-formed. No function is implicitly declared by such a
 call. — *end note*]
 If the *postfix-expression* names a destructor or pseudo-destructor
 [[expr.prim.id.dtor]], the type of the function call expression is
 `void`; otherwise, the type of the function call expression is the
 return type of the statically chosen function (i.e., ignoring the
 `virtual` keyword), even if the type of the function actually called is
+different. If the *postfix-expression* names a pseudo-destructor (in
 which case the *postfix-expression* is a possibly-parenthesized class
 member access), the function call destroys the object of scalar type
+denoted by the object expression of the class member access
+[[expr.ref]], [[basic.life]].
+Calling a function through an expression whose function type `E` is
+different from the function type `F` of the called function’s definition
+results in undefined behavior unless the type “pointer to `F`” can be
+converted to the type “pointer to `E`” via a function pointer conversion
+[[conv.fctptr]].
+[*Note 4*: The exception applies when the expression has the type of a
+potentially-throwing function, but the called function has a
+non-throwing exception specification, and the function types are
+otherwise the same. — *end note*]
+When a function is called, each parameter [[dcl.fct]] is initialized
+[[dcl.init]], [[class.copy.ctor]] with its corresponding argument. If
+the function is an explicit object member function and there is an
+implied object argument [[over.call.func]], the list of provided
+arguments is preceded by the implied object argument for the purposes of
+this correspondence. If there is no corresponding argument, the default
+argument for the parameter is used.
 [*Example 1*:
 ``` cpp
 template<typename ...T> int f(int n = 0, T ...t);
 int x = f<int>();               // error: no argument for second function parameter
 ```
 — *end example*]
+If the function is an implicit object member function, the `this`
+parameter of the function [[expr.prim.this]] is initialized with a
+pointer to the object of the call, converted as if by an explicit type
+conversion [[expr.cast]].
 [*Note 5*: There is no access or ambiguity checking on this conversion;
 the access checking and disambiguation are done as part of the (possibly
 implicit) class member access operator. See  [[class.member.lookup]],
 [[class.access.base]], and  [[expr.ref]]. — *end note*]
 parameter occurs within the context of the calling function.
 [*Example 2*: The access of the constructor, conversion functions or
 destructor is checked at the point of call in the calling function. If a
 constructor or destructor for a function parameter throws an exception,
+the search for a handler starts in the calling function; in particular,
+if the function called has a *function-try-block* [[except.pre]] with a
+handler that can handle the exception, this handler is not
+considered. — *end example*]
 The *postfix-expression* is sequenced before each *expression* in the
 *expression-list* and any default argument. The initialization of a
 parameter, including every associated value computation and side effect,
 is indeterminately sequenced with respect to that of any other
 parameters, but these changes cannot affect the values of the arguments
 except where a parameter is of a reference type [[dcl.ref]]; if the
 reference is to a const-qualified type, `const_cast` is required to be
 used to cast away the constness in order to modify the argument’s value.
 Where a parameter is of `const` reference type a temporary object is
+introduced if needed
+[[dcl.type]], [[lex.literal]], [[lex.string]], [[dcl.array]], [[class.temporary]].
+In addition, it is possible to modify the values of non-constant objects
+through pointer parameters. — *end note*]
 A function can be declared to accept fewer arguments (by declaring
 default arguments [[dcl.fct.default]]) or more arguments (by using the
 ellipsis, `...`, or a function parameter pack [[dcl.fct]]) than the
 number of parameters in the function definition [[dcl.fct.def]].
 by a *braced-init-list* (the initializer) constructs a value of the
 specified type given the initializer. If the type is a placeholder for a
 deduced class type, it is replaced by the return type of the function
 selected by overload resolution for class template deduction
 [[over.match.class.deduct]] for the remainder of this subclause.
+Otherwise, if the type contains a placeholder type, it is replaced by
+the type determined by placeholder type deduction
+[[dcl.type.auto.deduct]].
+[*Example 1*:
+``` cpp
+struct A {};
+void f(A&);             // #1
+void f(A&&);            // #2
+A& g();
+void h() {
+  f(g());               // calls #1
+  f(A(g()));            // calls #2 with a temporary object
+  f(auto(g()));         // calls #2 with a temporary object
+}
+```
+— *end example*]
 If the initializer is a parenthesized single expression, the type
 conversion expression is equivalent to the corresponding cast expression
 [[expr.cast]]. Otherwise, if the type is cv `void` and the initializer
 is `()` or `{}` (after pack expansion, if any), the expression is a
+prvalue of type `void` that performs no initialization. Otherwise, the
+expression is a prvalue of the specified type whose result object is
+direct-initialized [[dcl.init]] with the initializer. If the initializer
+is a parenthesized optional *expression-list*, the specified type shall
+not be an array type.
 #### Class member access <a id="expr.ref">[[expr.ref]]</a>
 A postfix expression followed by a dot `.` or an arrow `->`, optionally
+followed by the keyword `template`, and then followed by an
+*id-expression*, is a postfix expression. The postfix expression before
+the dot or arrow is evaluated;[^12]
+the result of that evaluation, together with the *id-expression*,
+determines the result of the entire postfix expression.
+[*Note 1*: If the keyword `template` is used, the following unqualified
+name is considered to refer to a template [[temp.names]]. If a
+*simple-template-id* results and is followed by a `::`, the
+*id-expression* is a *qualified-id*. — *end note*]
 For the first option (dot) the first expression shall be a glvalue. For
 the second option (arrow) the first expression shall be a prvalue having
 pointer type. The expression `E1->E2` is converted to the equivalent
 form `(*(E1)).E2`; the remainder of [[expr.ref]] will address only the
 first option (dot).[^13]
 Abbreviating *postfix-expression*`.`*id-expression* as `E1.E2`, `E1` is
 called the *object expression*. If the object expression is of scalar
 type, `E2` shall name the pseudo-destructor of that same type (ignoring
+cv-qualifications) and `E1.E2` is a prvalue of type “function of ()
 returning `void`”.
+[*Note 2*: This value can only be used for a notional function call
 [[expr.prim.id.dtor]]. — *end note*]
 Otherwise, the object expression shall be of class type. The class type
 shall be complete unless the class member access appears in the
 definition of that class.
+[*Note 3*: The program is ill-formed if the result differs from that
+when the class is complete [[class.member.lookup]]. — *end note*]
+[*Note 4*:  [[basic.lookup.qual]] describes how names are looked up
 after the `.` and `->` operators. — *end note*]
 If `E2` is a bit-field, `E1.E2` is a bit-field. The type and value
 category of `E1.E2` are determined as follows. In the remainder of
 [[expr.ref]], *cq* represents either `const` or the absence of `const`
 and *vq* represents either `volatile` or the absence of `volatile`. *cv*
 represents an arbitrary set of cv-qualifiers, as defined in
 [[basic.type.qualifier]].
 If `E2` is declared to have type “reference to `T`”, then `E1.E2` is an
+lvalue of type `T`. If `E2` is a static data member, `E1.E2` designates
+the object or function to which the reference is bound, otherwise
+`E1.E2` designates the object or function to which the corresponding
+reference member of `E1` is bound. Otherwise, one of the following rules
+applies.
 - If `E2` is a static data member and the type of `E2` is `T`, then
   `E1.E2` is an lvalue; the expression designates the named member of
   the class. The type of `E1.E2` is `T`.
 - If `E2` is a non-static data member and the type of `E1` is “*cq1 vq1*
   *cq12* stand for the “union” of *cq1* and *cq2*; that is, if *cq1* or
   *cq2* is `const`, then *cq12* is `const`. If `E2` is declared to be a
   `mutable` member, then the type of `E1.E2` is “*vq12* `T`”. If `E2` is
   not declared to be a `mutable` member, then the type of `E1.E2` is
   “*cq12* *vq12* `T`”.
+- If `E2` is an overload set, function overload resolution
+  [[over.match]] is used to select the function to which `E2` refers.
+  The type of `E1.E2` is the type of `E2` and `E1.E2` refers to the
+  function referred to by `E2`.
   - If `E2` refers to a static member function, `E1.E2` is an lvalue.
   - Otherwise (when `E2` refers to a non-static member function),
     `E1.E2` is a prvalue. The expression can be used only as the
     left-hand operand of a member function call [[class.mfct]].
     \[*Note 5*: Any redundant set of parentheses surrounding the
     expression is ignored [[expr.prim.paren]]. — *end note*]
 - If `E2` is a nested type, the expression `E1.E2` is ill-formed.
 - If `E2` is a member enumerator and the type of `E2` is `T`, the
+  expression `E1.E2` is a prvalue of type `T` whose value is the value
+  of the enumerator.
+If `E2` is a non-static member, the program is ill-formed if the class
+of which `E2` is directly a member is an ambiguous base
+[[class.member.lookup]] of the naming class [[class.access.base]] of
+`E2`.
 [*Note 6*: The program is also ill-formed if the naming class is an
 ambiguous base of the class type of the object expression; see
 [[class.access.base]]. — *end note*]
+If `E2` is a non-static member and the result of `E1` is an object whose
+type is not similar [[conv.qual]] to the type of `E1`, the behavior is
+undefined.
+[*Example 1*:
+``` cpp
+struct A { int i; };
+struct B { int j; };
+struct D : A, B {};
+void f() {
+  D d;
+  static_cast<B&>(d).j;             // OK, object expression designates the B subobject of d
+  reinterpret_cast<B&>(d).j;        // undefined behavior
+}
+```
+— *end example*]
 #### Increment and decrement <a id="expr.post.incr">[[expr.post.incr]]</a>
 The value of a postfix `++` expression is the value of its operand.
 [*Note 1*: The value obtained is a copy of the original
 version of the type of the operand. If the operand is a bit-field that
 cannot represent the incremented value, the resulting value of the
 bit-field is *implementation-defined*. See also  [[expr.add]] and
 [[expr.ass]].
+The operand of postfix `--` is decremented analogously to the postfix
 `++` operator.
 [*Note 3*: For prefix increment and decrement, see
 [[expr.pre.incr]]. — *end note*]
 such that `B` is a base class of `D`, the result is a pointer to the
 unique `B` subobject of the `D` object pointed to by `v`, or a null
 pointer value if `v` is a null pointer value. Similarly, if `T` is
 “reference to *cv1* `B`” and `v` has type *cv2* `D` such that `B` is a
 base class of `D`, the result is the unique `B` subobject of the `D`
+object referred to by `v`.[^14]
+In both the pointer and reference cases, the program is ill-formed if
+`B` is an inaccessible or ambiguous base class of `D`.
 [*Example 1*:
 ``` cpp
 struct B { };
 If `T` is “pointer to cv `void`”, then the result is a pointer to the
 most derived object pointed to by `v`. Otherwise, a runtime check is
 applied to see if the object pointed or referred to by `v` can be
 converted to the type pointed or referred to by `T`.
+Let `C` be the class type to which `T` points or refers. The runtime
 check logically executes as follows:
 - If, in the most derived object pointed (referred) to by `v`, `v`
   points (refers) to a public base class subobject of a `C` object, and
   if only one object of type `C` is derived from the subobject pointed
 The result of a `typeid` expression is an lvalue of static type `const`
 `std::type_info` [[type.info]] and dynamic type `const` `std::type_info`
 or `const` *name* where *name* is an *implementation-defined* class
 publicly derived from `std::type_info` which preserves the behavior
+described in  [[type.info]].[^15]
+The lifetime of the object referred to by the lvalue extends to the end
+of the program. Whether or not the destructor is called for the
+`std::type_info` object at the end of the program is unspecified.
+If the type of the *expression* or *type-id* operand is a (possibly
+cv-qualified) class type or a reference to (possibly cv-qualified) class
+type, that class shall be completely defined.
 When `typeid` is applied to a glvalue whose type is a polymorphic class
 type [[class.virtual]], the result refers to a `std::type_info` object
 representing the type of the most derived object [[intro.object]] (that
 is, the dynamic type) to which the glvalue refers. If the glvalue is
+obtained by applying the unary `*` operator to a pointer[^16]
+and the pointer is a null pointer value [[basic.compound]], the `typeid`
 expression throws an exception [[except.throw]] of a type that would
 match a handler of type `std::bad_typeid` exception [[bad.typeid]].
 When `typeid` is applied to an expression other than a glvalue of a
 polymorphic class type, the result refers to a `std::type_info` object
 representing the static type of the expression. Lvalue-to-rvalue
 [[conv.lval]], array-to-pointer [[conv.array]], and function-to-pointer
 [[conv.func]] conversions are not applied to the expression. If the
 expression is a prvalue, the temporary materialization conversion
 [[conv.rval]] is applied. The expression is an unevaluated operand
+[[term.unevaluated.operand]].
 When `typeid` is applied to a *type-id*, the result refers to a
 `std::type_info` object representing the type of the *type-id*. If the
 type of the *type-id* is a reference to a possibly cv-qualified type,
 the result of the `typeid` expression refers to a `std::type_info`
+object representing the cv-unqualified referenced type.
 [*Note 1*: The *type-id* cannot denote a function type with a
 *cv-qualifier-seq* or a *ref-qualifier* [[dcl.fct]]. — *end note*]
 If the type of the expression or *type-id* is a cv-qualified type, the
 typeid(D)  == typeid(const D&); // yields true
 ```
 — *end example*]
+The type `std::type_info` [[type.info]] is not predefined; if a standard
+library declaration [[typeinfo.syn]], [[std.modules]] of
+`std::type_info` does not precede [[basic.lookup.general]] a `typeid`
+expression, the program is ill-formed.
 [*Note 2*: Subclause [[class.cdtor]] describes the behavior of `typeid`
 applied to an object under construction or destruction. — *end note*]
 #### Static cast <a id="expr.static.cast">[[expr.static.cast]]</a>
 static_cast<D&>(br);            // produces lvalue denoting the original d object
 ```
 — *end example*]
+An lvalue of type `T1` can be cast to type “rvalue reference to `T2`” if
+`T2` is reference-compatible with `T1` [[dcl.init.ref]]. If the value is
+not a bit-field, the result refers to the object or the specified base
+class subobject thereof; otherwise, the lvalue-to-rvalue conversion
+[[conv.lval]] is applied to the bit-field and the resulting prvalue is
+used as the operand of the `static_cast` for the remainder of this
+subclause. If `T2` is an inaccessible [[class.access]] or ambiguous
+[[class.member.lookup]] base class of `T1`, a program that necessitates
+such a cast is ill-formed.
 An expression E can be explicitly converted to a type `T` if there is an
 implicit conversion sequence [[over.best.ics]] from E to `T`, if
 overload resolution for a direct-initialization [[dcl.init]] of an
 object or reference of type `T` from E would find at least one viable
 Otherwise, the `static_cast` shall perform one of the conversions listed
 below. No other conversion shall be performed explicitly using a
 `static_cast`.
 Any expression can be explicitly converted to type cv `void`, in which
+case the operand is a discarded-value expression [[expr.prop]].
+[*Note 3*: Such a `static_cast` has no result as it is a prvalue of
+type `void`; see  [[basic.lval]]. — *end note*]
+[*Note 4*: However, if the value is in a temporary object
 [[class.temporary]], the destructor for that object is not executed
 until the usual time, and the value of the object is preserved for the
 purpose of executing the destructor. — *end note*]
 The inverse of any standard conversion sequence [[conv]] not containing
 that of converting from the original value to the floating-point type.
 A value of integral or enumeration type can be explicitly converted to a
 complete enumeration type. If the enumeration type has a fixed
 underlying type, the value is first converted to that type by integral
+promotion [[conv.prom]] or integral conversion [[conv.integral]], if
+necessary, and then to the enumeration type. If the enumeration type
+does not have a fixed underlying type, the value is unchanged if the
+original value is within the range of the enumeration values
+[[dcl.enum]], and otherwise, the behavior is undefined. A value of
+floating-point type can also be explicitly converted to an enumeration
+type. The resulting value is the same as converting the original value
+to the underlying type of the enumeration [[conv.fpint]], and
+subsequently to the enumeration type.
+A prvalue of floating-point type can be explicitly converted to any
+other floating-point type. If the source value can be exactly
+represented in the destination type, the result of the conversion has
+that exact representation. If the source value is between two adjacent
+destination values, the result of the conversion is an
+*implementation-defined* choice of either of those values. Otherwise,
+the behavior is undefined.
 A prvalue of type “pointer to *cv1* `B`”, where `B` is a class type, can
 be converted to a prvalue of type “pointer to *cv2* `D`”, where `D` is a
 complete class derived [[class.derived]] from `B`, if *cv2* is the same
 cv-qualification as, or greater cv-qualification than, *cv1*. If `B` is
 a virtual base class of `D` or a base class of a virtual base class of
 `D`, or if no valid standard conversion from “pointer to `D`” to
 “pointer to `B`” exists [[conv.ptr]], the program is ill-formed. The
 null pointer value [[basic.compound]] is converted to the null pointer
 value of the destination type. If the prvalue of type “pointer to *cv1*
+`B`” points to a `B` that is actually a base class subobject of an
+object of type `D`, the resulting pointer points to the enclosing object
+of type `D`. Otherwise, the behavior is undefined.
 A prvalue of type “pointer to member of `D` of type *cv1* `T`” can be
 converted to a prvalue of type “pointer to member of `B` of type *cv2*
 `T`”, where `D` is a complete class type and `B` is a base class
 [[class.derived]] of `D`, if *cv2* is the same cv-qualification as, or
 greater cv-qualification than, *cv1*.
+[*Note 5*: Function types (including those used in
 pointer-to-member-function types) are never cv-qualified
 [[dcl.fct]]. — *end note*]
 If no valid standard conversion from “pointer to member of `B` of type
 `T`” to “pointer to member of `D` of type `T`” exists [[conv.mem]], the
 class `B` contains the original member, or is a base or derived class of
 the class containing the original member, the resulting pointer to
 member points to the original member. Otherwise, the behavior is
 undefined.
+[*Note 6*: Although class `B` need not contain the original member, the
 dynamic type of the object with which indirection through the pointer to
 member is performed must contain the original member; see
 [[expr.mptr.oper]]. — *end note*]
 A prvalue of type “pointer to *cv1* `void`” can be converted to a
 *cv2* is the same cv-qualification as, or greater cv-qualification than,
 *cv1*. If the original pointer value represents the address `A` of a
 byte in memory and `A` does not satisfy the alignment requirement of
 `T`, then the resulting pointer value is unspecified. Otherwise, if the
 original pointer value points to an object *a*, and there is an object
+*b* of type similar to `T` that is pointer-interconvertible
+[[basic.compound]] with *a*, the result is a pointer to *b*. Otherwise,
+the pointer value is unchanged by the conversion.
 [*Example 3*:
 ``` cpp
 T* p1 = new T;
 to a pointer. A pointer converted to an integer of sufficient size (if
 any such exists on the implementation) and back to the same pointer type
 will have its original value; mappings between pointers and integers are
 otherwise *implementation-defined*.
 A function pointer can be explicitly converted to a function pointer of
 a different type.
+[*Note 4*: The effect of calling a function through a pointer to a
 function type [[dcl.fct]] that is not the same as the type used in the
 definition of the function is undefined [[expr.call]]. — *end note*]
 Except that converting a prvalue of type “pointer to `T1`” to the type
 “pointer to `T2`” (where `T1` and `T2` are function types) and back to
 its original type yields the original pointer value, the result of such
 a pointer conversion is unspecified.
+[*Note 5*: See also  [[conv.ptr]] for more details of pointer
 conversions. — *end note*]
 An object pointer can be explicitly converted to an object pointer of a
+different type.[^17]
+When a prvalue `v` of object pointer type is converted to the object
+pointer type “pointer to cv `T`”, the result is
 `static_cast<cv T*>(static_cast<cv~void*>(v))`.
+[*Note 6*: Converting a pointer of type “pointer to `T1`” that points
+to an object of type `T1` to the type “pointer to `T2`” (where `T2` is
+an object type and the alignment requirements of `T2` are no stricter
+than those of `T1`) and back to its original type yields the original
+pointer value. — *end note*]
 Converting a function pointer to an object pointer type or vice versa is
 conditionally-supported. The meaning of such a conversion is
 *implementation-defined*, except that if an implementation supports
 conversions in both directions, converting a prvalue of one type to the
 yield the original pointer value.
 The null pointer value [[basic.compound]] is converted to the null
 pointer value of the destination type.
+[*Note 7*: A null pointer constant of type `std::nullptr_t` cannot be
 converted to a pointer type, and a null pointer constant of integral
 type is not necessarily converted to a null pointer
 value. — *end note*]
 A prvalue of type “pointer to member of `X` of type `T1`” can be
 explicitly converted to a prvalue of a different type “pointer to member
 of `Y` of type `T2`” if `T1` and `T2` are both function types or both
+object types.[^18]
+The null member pointer value [[conv.mem]] is converted to the null
+member pointer value of the destination type. The result of this
+conversion is unspecified, except in the following cases:
 - Converting a prvalue of type “pointer to member function” to a
   different pointer-to-member-function type and back to its original
   type yields the original pointer-to-member value.
 - Converting a prvalue of type “pointer to data member of `X` of type
 Conversions that can be performed explicitly using `const_cast` are
 listed below. No other conversion shall be performed explicitly using
 `const_cast`.
 [*Note 1*: Subject to the restrictions in this subclause, an expression
+can be cast to its own type using a `const_cast`
 operator. — *end note*]
 For two similar types `T1` and `T2` [[conv.qual]], a prvalue of type
 `T1` may be explicitly converted to the type `T2` using a `const_cast`
+if, considering the qualification-decompositions of both types, each P¹ᵢ
+is the same as P²ᵢ for all i. The result of a `const_cast` refers to the
 original entity.
 [*Example 1*:
 ``` cpp
 A null pointer value [[basic.compound]] is converted to the null pointer
 value of the destination type. The null member pointer value
 [[conv.mem]] is converted to the null member pointer value of the
 destination type.
+[*Note 2*:
+Depending on the type of the object, a write operation through the
+pointer, lvalue or pointer to data member resulting from a `const_cast`
+that casts away a const-qualifier[^20]
+can produce undefined behavior [[dcl.type.cv]].
+— *end note*]
 A conversion from a type `T1` to a type `T2` *casts away constness* if
+`T1` and `T2` are different, there is a qualification-decomposition
+[[conv.qual]] of `T1` yielding *n* such that `T2` has a
+qualification-decomposition of the form
 and there is no qualification conversion that converts `T1` to
 Casting from an lvalue of type `T1` to an lvalue of type `T2` using an
 lvalue reference cast or casting from an expression of type `T1` to an
 xvalue of type `T2` using an rvalue reference cast casts away constness
 if a cast from a prvalue of type “pointer to `T1`” to the type “pointer
 to `T2`” casts away constness.
 [*Note 3*: Some conversions which involve only changes in
+cv-qualification cannot be done using `const_cast`. For instance,
 conversions between pointers to functions are not covered because such
 conversions lead to values whose use causes undefined behavior. For the
 same reasons, conversions between pointers to member functions, and in
 particular, the conversion from a pointer to a const member function to
 a pointer to a non-const member function, are not
 covered. — *end note*]
 ### Unary expressions <a id="expr.unary">[[expr.unary]]</a>
+#### General <a id="expr.unary.general">[[expr.unary.general]]</a>
 Expressions with unary operators group right-to-left.
 ``` bnf
+%% Ed. note: character protrusion would misalign operators.
 unary-expression:
     postfix-expression
     unary-operator cast-expression
     '++' cast-expression
+    '--' cast-expression
     await-expression
     sizeof unary-expression
     sizeof '(' type-id ')'
     sizeof '...' '(' identifier ')'
     alignof '(' type-id ')'
     new-expression
     delete-expression
 ```
 ``` bnf
+%% Ed. note: character protrusion would misalign operators.
 unary-operator: one of
     '* & + - ! ~'
 ```
 #### Unary operators <a id="expr.unary.op">[[expr.unary.op]]</a>
+The unary `*` operator performs *indirection*. Its operand shall be a
+prvalue of type “pointer to `T`”, where `T` is an object or function
+type. The operator yields an lvalue of type `T` denoting the object or
+function to which the operand points.
 [*Note 1*:  Indirection through a pointer to an incomplete type (other
 than cv `void`) is valid. The lvalue thus obtained can be used in
 limited ways (to initialize a reference, for example); this lvalue must
 not be converted to a prvalue, see  [[conv.lval]]. — *end note*]
+Each of the following unary operators yields a prvalue.
+The operand of the unary `&` operator shall be an lvalue of some type
+`T`. The result is a prvalue.
 - If the operand is a *qualified-id* naming a non-static or variant
+  member `m` of some class `C`, other than an explicit object member
+ function, the result has type “pointer to member of class `C` of type
+ `T`” and designates `C::m`.
+- Otherwise, the result has type “pointer to `T`” and points to the
+ designated object [[intro.memory]] or function [[basic.compound]]. If
+ the operand names an explicit object member function [[dcl.fct]], the
+ operand shall be a *qualified-id*. \[*Note 2*: In particular, taking
+ the address of a variable of type “cv `T`” yields a pointer of type
+  “pointer to cv `T`”. — *end note*]
 [*Example 1*:
 ``` cpp
 struct A { int i; };
 If `&` is applied to an lvalue of incomplete class type and the complete
 type declares `operator&()`, it is unspecified whether the operator has
 the built-in meaning or the operator function is called. The operand of
 `&` shall not be a bit-field.
+[*Note 5*: The address of an overload set [[over]] can be taken only in
+a context that uniquely determines which function is referred to (see
+[[over.over]]). Since the context can affect whether the operand is a
+static or non-static member function, the context can also affect
+whether the expression has type “pointer to function” or “pointer to
+member function”. — *end note*]
 The operand of the unary `+` operator shall have arithmetic, unscoped
 enumeration, or pointer type and the result is the value of the
 argument. Integral promotion is performed on integral or enumeration
 operands. The type of the result is the type of the promoted operand.
 The operand of the unary `-` operator shall have arithmetic or unscoped
+enumeration type and the result is the negative of its operand. Integral
 promotion is performed on integral or enumeration operands. The negative
 of an unsigned quantity is computed by subtracting its value from 2ⁿ,
 where n is the number of bits in the promoted operand. The type of the
 result is the type of the promoted operand.
+[*Note 6*: The result is the two’s complement of the operand (where
+operand and result are considered as unsigned). — *end note*]
 The operand of the logical negation operator `!` is contextually
 converted to `bool` [[conv]]; its value is `true` if the converted
 operand is `false` and `false` otherwise. The type of the result is
 `bool`.
+The operand of the `~` operator shall have integral or unscoped
+enumeration type. Integral promotions are performed. The type of the
+result is the type of the promoted operand. Given the coefficients `xᵢ`
+of the base-2 representation [[basic.fundamental]] of the promoted
+operand `x`, the coefficient `rᵢ` of the base-2 representation of the
+result `r` is 1 if `xᵢ` is 0, and 0 otherwise.
+[*Note 7*: The result is the ones’ complement of the operand (where
+operand and result are considered as unsigned). — *end note*]
 There is an ambiguity in the grammar when `~` is followed by a
 *type-name* or *decltype-specifier*. The ambiguity is resolved by
+treating `~` as the operator rather than as the start of an
+*unqualified-id* naming a destructor.
+[*Note 8*: Because the grammar does not permit an operator to follow
 the `.`, `->`, or `::` tokens, a `~` followed by a *type-name* or
 *decltype-specifier* in a member access expression or *qualified-id* is
 unambiguously parsed as a destructor name. — *end note*]
 #### Increment and decrement <a id="expr.pre.incr">[[expr.pre.incr]]</a>
 bit-field. The expression `++x` is equivalent to `x+=1`.
 [*Note 1*: See the discussions of addition [[expr.add]] and assignment
 operators [[expr.ass]] for information on conversions. — *end note*]
+The operand of prefix `--` is modified [[defns.access]] by subtracting
+`1`. The requirements on the operand of prefix `--` and the properties
 of its result are otherwise the same as those of prefix `++`.
 [*Note 2*: For postfix increment and decrement, see
 [[expr.post.incr]]. — *end note*]
 ```
 An *await-expression* shall appear only in a potentially-evaluated
 expression within the *compound-statement* of a *function-body* outside
 of a *handler* [[except.pre]]. In a *declaration-statement* or in the
+*simple-declaration* (if any) of an *init-statement*, an
 *await-expression* shall appear only in an *initializer* of that
 *declaration-statement* or *simple-declaration*. An *await-expression*
 shall not appear in a default argument [[dcl.fct.default]]. An
+*await-expression* shall not appear in the initializer of a block
 variable with static or thread storage duration. A context within a
 function where an *await-expression* can appear is called a *suspension
 context* of the function.
 Evaluation of an *await-expression* involves the following auxiliary
 types, expressions, and objects:
 - *p* is an lvalue naming the promise object [[dcl.fct.def.coroutine]]
   of the enclosing coroutine and `P` is the type of that object.
+- Unless the *await-expression* was implicitly produced by a
+  *yield-expression* [[expr.yield]], an initial await expression, or a
+  final await expression [[dcl.fct.def.coroutine]], a search is
+ performed for the name `await_transform` in the scope of `P`
+  [[class.member.lookup]]. If this search is performed and finds at
+  least one declaration, then *a* is
   *p*`.await_transform(`*cast-expression*`)`; otherwise, *a* is the
   *cast-expression*.
 - *o* is determined by enumerating the applicable `operator co_await`
   functions for an argument *a* [[over.match.oper]], and choosing the
   best one through overload resolution [[over.match]]. If overload
 - If the result of *await-ready* is `false`, the coroutine is considered
   suspended. Then:
   - If the type of *await-suspend* is `std::coroutine_handle<Z>`,
     *await-suspend*`.resume()` is evaluated. \[*Note 1*: This resumes
     the coroutine referred to by the result of *await-suspend*. Any
+    number of coroutines can be successively resumed in this fashion,
     eventually returning control flow to the current coroutine caller or
     resumer [[dcl.fct.def.coroutine]]. — *end note*]
   - Otherwise, if the type of *await-suspend* is `bool`, *await-suspend*
     is evaluated, and the coroutine is resumed if the result is `false`.
   - Otherwise, *await-suspend* is evaluated.
   If the evaluation of *await-suspend* exits via an exception, the
   exception is caught, the coroutine is resumed, and the exception is
+  immediately rethrown [[except.throw]]. Otherwise, control flow returns
+  to the current coroutine caller or resumer [[dcl.fct.def.coroutine]]
+  without exiting any scopes [[stmt.jump]]. The point in the coroutine
+  immediately prior to control returning to its caller or resumer is a
+  coroutine *suspend point*.
 - If the result of *await-ready* is `true`, or when the coroutine is
+  resumed other than by rethrowing an exception from *await-suspend*,
+  the *await-resume* expression is evaluated, and its result is the
+  result of the *await-expression*.
+[*Note 2*: With respect to sequencing, an *await-expression* is
+indivisible [[intro.execution]]. — *end note*]
 [*Example 1*:
 ``` cpp
 template <typename T>
 using namespace std::chrono;
 my_future<int> h();
 my_future<void> g() {
+  std::cout << "just about to go to sleep...\n";
   co_await 10ms;
   std::cout << "resumed\n";
   co_await h();
 }
 #### Sizeof <a id="expr.sizeof">[[expr.sizeof]]</a>
 The `sizeof` operator yields the number of bytes occupied by a
 non-potentially-overlapping object of the type of its operand. The
 operand is either an expression, which is an unevaluated operand
+[[term.unevaluated.operand]], or a parenthesized *type-id*. The `sizeof`
+operator shall not be applied to an expression that has function or
+incomplete type, to the parenthesized name of such types, or to a
+glvalue that designates a bit-field. The result of `sizeof` applied to
+any of the narrow character types is `1`. The result of `sizeof` applied
+to any other fundamental type [[basic.fundamental]] is
+*implementation-defined*.
+[*Note 1*:
+In particular, the values of `sizeof(bool)`, `sizeof(char16_t)`,
 `sizeof(char32_t)`, and `sizeof(wchar_t)` are
+implementation-defined.[^21]
+— *end note*]
 [*Note 2*: See  [[intro.memory]] for the definition of byte and
+[[term.object.representation]] for the definition of object
 representation. — *end note*]
 When applied to a reference type, the result is the size of the
 referenced type. When applied to a class, the result is the number of
 bytes in an object of that class including any padding required for
 placing objects of that type in an array. The result of applying
 `sizeof` to a potentially-overlapping subobject is the size of the type,
+not the size of the subobject.[^22]
+When applied to an array, the result is the total number of bytes in the
+array. This implies that the size of an array of n elements is n times
+the size of an element.
 The lvalue-to-rvalue [[conv.lval]], array-to-pointer [[conv.array]], and
 function-to-pointer [[conv.func]] standard conversions are not applied
 to the operand of `sizeof`. If the operand is a prvalue, the temporary
 materialization conversion [[conv.rval]] is applied.
 The result of `sizeof` and `sizeof...` is a prvalue of type
 `std::size_t`.
 [*Note 3*: A `sizeof` expression is an integral constant expression
 [[expr.const]]. The type `std::size_t` is defined in the standard header
+`<cstddef>` [[cstddef.syn]], [[support.types.layout]]. — *end note*]
 #### Alignof <a id="expr.alignof">[[expr.alignof]]</a>
 An `alignof` expression yields the alignment requirement of its operand
 type. The operand shall be a *type-id* representing a complete object
 The result is a prvalue of type `std::size_t`.
 [*Note 1*: An `alignof` expression is an integral constant expression
 [[expr.const]]. The type `std::size_t` is defined in the standard header
+`<cstddef>` [[cstddef.syn]], [[support.types.layout]]. — *end note*]
 When `alignof` is applied to a reference type, the result is the
 alignment of the referenced type. When `alignof` is applied to an array
 type, the result is the alignment of the element type.
 #### `noexcept` operator <a id="expr.unary.noexcept">[[expr.unary.noexcept]]</a>
 The `noexcept` operator determines whether the evaluation of its
+operand, which is an unevaluated operand [[term.unevaluated.operand]],
+can throw an exception [[except.throw]].
 ``` bnf
 noexcept-expression:
   noexcept '(' expression ')'
 ```
 #### New <a id="expr.new">[[expr.new]]</a>
 The *new-expression* attempts to create an object of the *type-id*
 [[dcl.name]] or *new-type-id* to which it is applied. The type of that
 object is the *allocated type*. This type shall be a complete object
+type [[term.incomplete.type]], but not an abstract class type
+[[class.abstract]] or array thereof [[intro.object]].
 [*Note 1*: Because references are not objects, references cannot be
 created by *new-expression*s. — *end note*]
+[*Note 2*: The *type-id* can be a cv-qualified type, in which case the
 object created by the *new-expression* has a cv-qualified
 type. — *end note*]
 ``` bnf
 new-expression:
 — *end example*]
 — *end note*]
 The *attribute-specifier-seq* in a *noptr-new-declarator* appertains to
 the associated array type.
 Every *constant-expression* in a *noptr-new-declarator* shall be a
 converted constant expression [[expr.const]] of type `std::size_t` and
 `n` is not a constant expression). — *end example*]
 If the *type-id* or *new-type-id* denotes an array type of unknown bound
 [[dcl.array]], the *new-initializer* shall not be omitted; the allocated
 object is an array with `n` elements, where `n` is determined from the
+number of initial elements supplied in the *new-initializer*
+[[dcl.init.aggr]], [[dcl.init.string]].
 If the *expression* in a *noptr-new-declarator* is present, it is
 implicitly converted to `std::size_t`. The *expression* is erroneous if:
 - the expression is of non-class type and its value before converting to
   terminating `'\0'` in a *string-literal* [[lex.string]]) exceeds the
   number of elements to initialize.
 If the *expression* is erroneous after converting to `std::size_t`:
+- if the *expression* is a potentially-evaluated core constant
+ expression, the program is ill-formed;
 - otherwise, an allocation function is not called; instead
   - if the allocation function that would have been called has a
     non-throwing exception specification [[except.spec]], the value of
     the *new-expression* is the null pointer value of the required
     result type;
     `std::bad_array_new_length` [[new.badlength]].
 When the value of the *expression* is zero, the allocation function is
 called to allocate an array with no elements.
+Objects created by a *new-expression* have dynamic storage duration
+[[basic.stc.dynamic]].
+[*Note 5*:  The lifetime of such an object is not necessarily
+restricted to the scope in which it is created. — *end note*]
+When the allocated type is “array of `N` `T`” (that is, the
+*noptr-new-declarator* syntax is used or the *new-type-id* or *type-id*
+denotes an array type), the *new-expression* yields a prvalue of type
+“pointer to `T`” that points to the initial element (if any) of the
+array. Otherwise, let `T` be the allocated type; the *new-expression* is
+a prvalue of type “pointer to T” that points to the object created.
+[*Note 6*: Both `new int` and `new int[10]` have type `int*` and the
+type of `new int[i][10]` is `int (*)[10]`. — *end note*]
 A *new-expression* may obtain storage for the object by calling an
 allocation function [[basic.stc.dynamic.allocation]]. If the
 *new-expression* terminates by throwing an exception, it may release
 storage by calling a deallocation function
 [[basic.stc.dynamic.deallocation]]. If the allocated type is a non-array
 deallocation function’s name is `operator delete`. If the allocated type
 is an array type, the allocation function’s name is `operator new[]` and
 the deallocation function’s name is `operator delete[]`.
 [*Note 7*: An implementation is required to provide default definitions
+for the global allocation functions
+[[basic.stc.dynamic]], [[new.delete.single]], [[new.delete.array]]. A
+C++ program can provide alternative definitions of these functions
+[[replacement.functions]] and/or class-specific versions [[class.free]].
+The set of allocation and deallocation functions that can be called by a
+*new-expression* can include functions that do not perform allocation or
+deallocation; for example, see [[new.delete.placement]]. — *end note*]
+If the *new-expression* does not begin with a unary `::` operator and
+the allocated type is a class type `T` or array thereof, a search is
+performed for the allocation function’s name in the scope of `T`
+[[class.member.lookup]]. Otherwise, or if nothing is found, the
+allocation function’s name is looked up by searching for it in the
+global scope.
 An implementation is allowed to omit a call to a replaceable global
+allocation function [[new.delete.single]], [[new.delete.array]]. When it
+does so, the storage is instead provided by the implementation or
 provided by extending the allocation of another *new-expression*.
 During an evaluation of a constant expression, a call to an allocation
 function is always omitted.
 — *end example*]
 [*Note 10*: Unless an allocation function has a non-throwing exception
 specification [[except.spec]], it indicates failure to allocate storage
+by throwing a `std::bad_alloc` exception
+[[basic.stc.dynamic.allocation]], [[except]], [[bad.alloc]]; it returns
 a non-null pointer otherwise. If the allocation function has a
 non-throwing exception specification, it returns null to indicate
 failure to allocate storage and a non-null pointer
 otherwise. — *end note*]
 the allocated object is sequenced before the value computation of the
 *new-expression*.
 If the *new-expression* creates an object or an array of objects of
 class type, access and ambiguity control are done for the allocation
+function, the deallocation function [[basic.stc.dynamic.deallocation]],
+and the constructor [[class.ctor]] selected for the initialization (if
+any). If the *new-expression* creates an array of objects of class type,
+the destructor is potentially invoked [[class.dtor]].
+If any part of the object initialization described above[^24]
+terminates by throwing an exception and a suitable deallocation function
+can be found, the deallocation function is called to free the memory in
+which the object was being constructed, after which the exception
+continues to propagate in the context of the *new-expression*. If no
+unambiguous matching deallocation function can be found, propagating the
+exception does not cause the object’s memory to be freed.
 [*Note 13*: This is appropriate when the called allocation function
 does not allocate memory; otherwise, it is likely to result in a memory
 leak. — *end note*]
+If the *new-expression* does not begin with a unary `::` operator and
+the allocated type is a class type `T` or an array thereof, a search is
+performed for the deallocation function’s name in the scope of `T`.
+Otherwise, or if nothing is found, the deallocation function’s name is
+looked up by searching for it in the global scope.
 A declaration of a placement deallocation function matches the
 declaration of a placement allocation function if it has the same number
 of parameters and, after parameter transformations [[dcl.fct]], all
 parameter types except the first are identical. If the lookup finds a
 ```
 The first alternative is a *single-object delete expression*, and the
 second is an *array delete expression*. Whenever the `delete` keyword is
 immediately followed by empty square brackets, it shall be interpreted
+as the second alternative.[^25]
+The operand shall be of pointer to object type or of class type. If of
+class type, the operand is contextually implicitly converted [[conv]] to
+a pointer to object type.[^26]
+The *delete-expression* has type `void`.
 If the operand has a class type, the operand is converted to a pointer
 type by calling the above-mentioned conversion function, and the
 converted operand is used in place of the original operand for the
 remainder of this subclause. In a single-object delete expression, the
 value of the operand of `delete` may be a null pointer value, a pointer
+value that resulted from a previous non-array *new-expression*, or a
+pointer to a base class subobject of an object created by such a
+*new-expression*. If not, the behavior is undefined. In an array delete
+expression, the value of the operand of `delete` may be a null pointer
+value or a pointer value that resulted from a previous array
+*new-expression* whose allocation function was not a non-allocating form
+[[new.delete.placement]].[^27]
+If not, the behavior is undefined.
 [*Note 1*: This means that the syntax of the *delete-expression* must
 match the type of the object allocated by `new`, not the syntax of the
 *new-expression*. — *end note*]
 *delete-expression*; it is not necessary to cast away the constness
 [[expr.const.cast]] of the pointer expression before it is used as the
 operand of the *delete-expression*. — *end note*]
 In a single-object delete expression, if the static type of the object
+to be deleted is not similar [[conv.qual]] to its dynamic type and the
+selected deallocation function (see below) is not a destroying operator
+delete, the static type shall be a base class of the dynamic type of the
+object to be deleted and the static type shall have a virtual destructor
+or the behavior is undefined. In an array delete expression, if the
+dynamic type of the object to be deleted is not similar to its static
+type, the behavior is undefined.
 The *cast-expression* in a *delete-expression* shall be evaluated
 exactly once.
 If the object being deleted has incomplete class type at the point of
 If the value of the operand of the *delete-expression* is a null pointer
 value, it is unspecified whether a deallocation function will be called
 as described above.
+If a deallocation function is called, it is `operator delete` for a
+single-object delete expression or `operator delete[]` for an array
+delete expression.
+[*Note 4*:  An implementation provides default definitions of the
+global deallocation functions
+[[new.delete.single]], [[new.delete.array]]. A C++ program can provide
+alternative definitions of these functions [[replacement.functions]],
+and/or class-specific versions [[class.free]]. — *end note*]
+If the keyword `delete` in a *delete-expression* is not preceded by the
+unary `::` operator and the type of the operand is a pointer to a
+(possibly cv-qualified) class type `T` or (possibly multidimensional)
+array thereof:
+- For a single-object delete expression, if the operand is a pointer to
+  cv `T` and `T` has a virtual destructor, the deallocation function is
+  the one selected at the point of definition of the dynamic type’s
+  virtual destructor [[class.dtor]].
+- Otherwise, a search is performed for the deallocation function’s name
+  in the scope of `T`.
+Otherwise, or if nothing is found, the deallocation function’s name is
+looked up by searching for it in the global scope. In any case, any
+declarations other than of usual deallocation functions
+[[basic.stc.dynamic.deallocation]] are discarded.
+[*Note 5*: If only a placement deallocation function is found in a
+class, the program is ill-formed because the lookup set is empty
+[[basic.lookup]]. — *end note*]
+If more than one deallocation function is found, the function to be
+called is selected as follows:
 - If any of the deallocation functions is a destroying operator delete,
   all deallocation functions that are not destroying operator deletes
   are eliminated from further consideration.
 - If the type has new-extended alignment, a function with a parameter of
   type `std::align_val_t` is preferred; otherwise a function without
   such a parameter is preferred. If any preferred functions are found,
   all non-preferred functions are eliminated from further consideration.
 - If exactly one function remains, that function is selected and the
   selection process terminates.
+- If the deallocation functions belong to a class scope, the one without
+ a parameter of type `std::size_t` is selected.
 - If the type is complete and if, for an array delete expression only,
   the operand is a pointer to a class type with a non-trivial destructor
+  or a (possibly multidimensional) array thereof, the function with a
   parameter of type `std::size_t` is selected.
 - Otherwise, it is unspecified whether a deallocation function with a
   parameter of type `std::size_t` is selected.
 For a single-object delete expression, the deleted object is the object
+A pointed to by the operand if the static type of A does not have a
+virtual destructor, and the most-derived object of A otherwise.
+[*Note 6*: If the deallocation function is not a destroying operator
 delete and the deleted object is not the most derived object in the
 former case, the behavior is undefined, as stated above. — *end note*]
 For an array delete expression, the deleted object is the array object.
 When a *delete-expression* is executed, the selected deallocation
 function shall be called with the address of the deleted object in a
 single-object delete expression, or the address of the deleted object
 suitably adjusted for the array allocation overhead [[expr.new]] in an
 array delete expression, as its first argument.
+[*Note 7*: Any cv-qualifiers in the type of the deleted object are
 ignored when forming this argument. — *end note*]
 If a destroying operator delete is used, an unspecified value is passed
 as the argument corresponding to the parameter of type
 `std::destroying_delete_t`. If a deallocation function with a parameter
 deallocation function with a parameter of type `std::size_t` is used,
 the size of the deleted object in a single-object delete expression, or
 of the array plus allocation overhead in an array delete expression, is
 passed as the corresponding argument.
+[*Note 8*: If this results in a call to a replaceable deallocation
 function, and either the first argument was not the result of a prior
 call to a replaceable allocation function or the second or third
 argument was not the corresponding argument in said call, the behavior
+is undefined [[new.delete.single]], [[new.delete.array]]. — *end note*]
 Access and ambiguity control are done for both the deallocation function
+and the destructor [[class.dtor]], [[class.free]].
 ### Explicit type conversion (cast notation) <a id="expr.cast">[[expr.cast]]</a>
 The result of the expression `(T)` *cast-expression* is of type `T`. The
 result is an lvalue if `T` is an lvalue reference type or an rvalue
 type “pointer to `U`” where `U` is either `T` or a class of which `T` is
 an unambiguous and accessible base class. The expression `E1->*E2` is
 converted into the equivalent form `(*(E1)).*E2`.
 Abbreviating *pm-expression*`.*`*cast-expression* as `E1.*E2`, `E1` is
+called the *object expression*. If the result of `E1` is an object whose
+type is not similar to the type of `E1`, or whose most derived object
+does not contain the member to which `E2` refers, the behavior is
+undefined. The expression `E1` is sequenced before the expression `E2`.
 The restrictions on cv-qualification, and the manner in which the
 cv-qualifiers of the operands are combined to produce the cv-qualifiers
 of the result, are the same as the rules for `E1.E2` given in
 [[expr.ref]].
 The binary `/` operator yields the quotient, and the binary `%` operator
 yields the remainder from the division of the first expression by the
 second. If the second operand of `/` or `%` is zero the behavior is
 undefined. For integral operands the `/` operator yields the algebraic
+quotient with any fractional part discarded;[^28]
+if the quotient `a/b` is representable in the type of the result,
+`(a/b)*b + a%b` is equal to `a`; otherwise, the behavior of both `a/b`
+and `a%b` is undefined.
 ### Additive operators <a id="expr.add">[[expr.add]]</a>
 The additive operators `+` and `-` group left-to-right. The usual
 arithmetic conversions [[expr.arith.conv]] are performed for operands of
   (possibly-hypothetical) array element i + j of `x` if 0 ≤ i + j ≤ n
   and the expression `P - J` points to the (possibly-hypothetical) array
   element i - j of `x` if 0 ≤ i - j ≤ n.
 - Otherwise, the behavior is undefined.
+[*Note 1*: Adding a value other than 0 or 1 to a pointer to a base
+class subobject, a member subobject, or a complete object results in
+undefined behavior. — *end note*]
 When two pointer expressions `P` and `Q` are subtracted, the type of the
 result is an *implementation-defined* signed integral type; this type
 shall be the same type that is defined as `std::ptrdiff_t` in the
 `<cstddef>` header [[support.types.layout]].
 - If `P` and `Q` both evaluate to null pointer values, the result is 0.
 - Otherwise, if `P` and `Q` point to, respectively, array elements i and
   j of the same array object `x`, the expression `P - Q` has the value
   i - j.
+- Otherwise, the behavior is undefined. \[*Note 2*: If the value i - j
   is not in the range of representable values of type `std::ptrdiff_t`,
   the behavior is undefined. — *end note*]
 For addition or subtraction, if the expressions `P` or `Q` have type
 “pointer to cv `T`”, where `T` and the array element type are not
 similar [[conv.qual]], the behavior is undefined.
+[*Example 1*:
+``` cpp
+int arr[5] = {1, 2, 3, 4, 5};
+unsigned int *p = reinterpret_cast<unsigned int*>(arr + 1);
+unsigned int k = *p;            // OK, value of k is 2[conv.lval]
+unsigned int *q = p + 1;        // undefined behavior: p points to an int, not an unsigned int object
+```
+— *end example*]
 ### Shift operators <a id="expr.shift">[[expr.shift]]</a>
 The shift operators `<<` and `>>` group left-to-right.
 If both operands have the same enumeration type `E`, the operator yields
 the result of converting the operands to the underlying type of `E` and
 applying `<=>` to the converted operands.
+If at least one of the operands is of object pointer type and the other
+operand is of object pointer or array type, array-to-pointer conversions
 [[conv.array]], pointer conversions [[conv.ptr]], and qualification
 conversions [[conv.qual]] are performed on both operands to bring them
 to their composite pointer type [[expr.type]]. After the conversions,
 the operands shall have the same type.
 [*Note 1*: If both of the operands are arrays, array-to-pointer
 conversions [[conv.array]] are not applied. — *end note*]
+In this case, `p <=> q` is of type `std::strong_ordering` and the result
+is defined by the following rules:
+- If two pointer operands `p` and `q` compare equal [[expr.eq]],
+  `p <=> q` yields `std::strong_ordering::equal`;
+- otherwise, if `p` and `q` compare unequal, `p <=> q` yields
   `std::strong_ordering::less` if `q` compares greater than `p` and
   `std::strong_ordering::greater` if `p` compares greater than `q`
+ [[expr.rel]];
+- otherwise, the result is unspecified.
 Otherwise, the program is ill-formed.
 The three comparison category types [[cmp.categories]] (the types
 `std::strong_ordering`, `std::weak_ordering`, and
+`std::partial_ordering`) are not predefined; if a standard library
+declaration [[compare.syn]], [[std.modules]] of such a class type does
+not precede [[basic.lookup.general]] a use of that type — even an
+implicit use in which the type is not named (e.g., via the `auto`
 specifier [[dcl.spec.auto]] in a defaulted three-way comparison
+[[class.spaceship]] or use of the built-in operator) — the program is
 ill-formed.
 ### Relational operators <a id="expr.rel">[[expr.rel]]</a>
 The relational operators group left-to-right.
 pointers, pointer conversions [[conv.ptr]] and qualification conversions
 [[conv.qual]] are performed to bring them to their composite pointer
 type [[expr.type]]. After conversions, the operands shall have the same
 type.
+The result of comparing unequal pointers to objects[^30]
+is defined in terms of a partial order consistent with the following
+rules:
 - If two pointers point to different elements of the same array, or to
   subobjects thereof, the pointer to the element with the higher
   subscript is required to compare greater.
 - If two pointers point to different non-static data members of the same
   object, or to subobjects of such members, recursively, the pointer to
+  the later declared member is required to compare greater provided
+ neither member is a subobject of zero size and their class is not a
+  union.
 - Otherwise, neither pointer is required to compare greater than the
   other.
 If two operands `p` and `q` compare equal [[expr.eq]], `p<=q` and `p>=q`
 both yield `true` and `p<q` and `p>q` both yield `false`. Otherwise, if
+a pointer to object `p` compares greater than a pointer `q`, `p>=q`,
+`p>q`, `q<=p`, and `q<p` all yield `true` and `p<=q`, `p<q`, `q>=p`, and
+`q>p` all yield `false`. Otherwise, the result of each of the operators
+is unspecified.
+[*Note 1*: A relational operator applied to unequal function pointers
+or to unequal pointers to `void` yields an unspecified
+result. — *end note*]
 If both operands (after conversions) are of arithmetic or enumeration
 type, each of the operators shall yield `true` if the specified
 relationship is true and `false` if it is false.
 The `^` operator groups left-to-right. The operands shall be of integral
 or unscoped enumeration type. The usual arithmetic conversions
 [[expr.arith.conv]] are performed. Given the coefficients `xᵢ` and `yᵢ`
 of the base-2 representation [[basic.fundamental]] of the converted
 operands `x` and `y`, the coefficient `rᵢ` of the base-2 representation
+of the result `r` is 1 if either (but not both) of `xᵢ` and `yᵢ` is 1,
 and 0 otherwise.
 [*Note 1*: The result is the bitwise exclusive function of the
 operands. — *end note*]
 The `|` operator groups left-to-right. The operands shall be of integral
 or unscoped enumeration type. The usual arithmetic conversions
 [[expr.arith.conv]] are performed. Given the coefficients `xᵢ` and `yᵢ`
 of the base-2 representation [[basic.fundamental]] of the converted
 operands `x` and `y`, the coefficient `rᵢ` of the base-2 representation
+of the result `r` is 1 if at least one of `xᵢ` and `yᵢ` is 1, and 0
 otherwise.
 [*Note 1*: The result is the bitwise inclusive function of the
 operands. — *end note*]
 Attempts are made to form an implicit conversion sequence from an
 operand expression `E1` of type `T1` to a target type related to the
 type `T2` of the operand expression `E2` as follows:
 - If `E2` is an lvalue, the target type is “lvalue reference to `T2`”,
+ but an implicit conversion sequence can only be formed if the
+ reference would bind directly [[dcl.init.ref]] to a glvalue.
 - If `E2` is an xvalue, the target type is “rvalue reference to `T2`”,
+ but an implicit conversion sequence can only be formed if the
+  reference would bind directly.
 - If `E2` is a prvalue or if neither of the conversion sequences above
   can be formed and at least one of the operands has (possibly
   cv-qualified) class type:
   - if `T1` and `T2` are the same class type (ignoring cv-qualification)
     and `T2` is at least as cv-qualified as `T1`, the target type is
 or if both are bit-fields.
 Otherwise, the result is a prvalue. If the second and third operands do
 not have the same type, and either has (possibly cv-qualified) class
 type, overload resolution is used to determine the conversions (if any)
+to be applied to the operands [[over.match.oper]], [[over.built]]. If
 the overload resolution fails, the program is ill-formed. Otherwise, the
 conversions thus determined are applied, and the converted operands are
 used in place of the original operands for the remainder of this
 subclause.
 A *yield-expression* shall appear only within a suspension context of a
 function [[expr.await]]. Let *e* be the operand of the
 *yield-expression* and *p* be an lvalue naming the promise object of the
 enclosing coroutine [[dcl.fct.def.coroutine]], then the
 *yield-expression* is equivalent to the expression
+`co_await p.yield_value(e)`.
 [*Example 1*:
 ``` cpp
 template <typename T>
   iterator begin();
   iterator end();
 };
 my_generator<pair<int,int>> g1() {
+  for (int i = 0; i < 10; ++i) co_yield {i,i};
 }
 my_generator<pair<int,int>> g2() {
+  for (int i = 0; i < 10; ++i) co_yield make_pair(i,i);
 }
 auto f(int x = co_yield 5);     // error: yield-expression outside of function suspension context
 int a[] = { co_yield 1 };       // error: yield-expression outside of function suspension context
 existing exception object; no new exception object is created. The
 exception is no longer considered to be caught.
 [*Example 1*:
+An exception handler that cannot completely handle the exception itself
+can be written like this:
 ``` cpp
 try {
   // ...
 } catch (...) {     // catch all exceptions
 ### Assignment and compound assignment operators <a id="expr.ass">[[expr.ass]]</a>
 The assignment operator (`=`) and the compound assignment operators all
 group right-to-left. All require a modifiable lvalue as their left
+operand; their result is an lvalue of the type of the left operand,
+referring to the left operand. The result in all cases is a bit-field if
+the left operand is a bit-field. In all cases, the assignment is
+sequenced after the value computation of the right and left operands,
+and before the value computation of the assignment expression. The right
+operand is sequenced before the left operand. With respect to an
+indeterminately-sequenced function call, the operation of a compound
+assignment is a single evaluation.
 [*Note 1*: Therefore, a function call cannot intervene between the
 lvalue-to-rvalue conversion and the side effect associated with any
 single compound assignment operator. — *end note*]
 When the left operand of an assignment operator is a bit-field that
 cannot represent the value of the expression, the resulting value of the
 bit-field is *implementation-defined*.
+An assignment whose left operand is of a volatile-qualified type is
+deprecated [[depr.volatile.type]] unless the (possibly parenthesized)
+assignment is a discarded-value expression or an unevaluated operand
+[[term.unevaluated.operand]].
 The behavior of an expression of the form `E1 op= E2` is equivalent to
+`E1 = E1 op E2` except that `E1` is evaluated only once.
+[*Note 2*: The object designated by `E1` is accessed
+twice. — *end note*]
+For `+=` and `-=`, `E1` shall either have arithmetic type or be a
+pointer to a possibly cv-qualified completely-defined object type. In
+all other cases, `E1` shall have arithmetic type.
 If the value being stored in an object is read via another object that
 overlaps in any way the storage of the first object, then the overlap
 shall be exact and the two objects shall have the same type, otherwise
 the behavior is undefined.
+[*Note 3*: This restriction applies to the relationship between the
 left and right sides of the assignment operation; it is not a statement
+about how the target of the assignment can be aliased in general. See
 [[basic.lval]]. — *end note*]
 A *braced-init-list* may appear on the right-hand side of
 - an assignment to a scalar, in which case the initializer list shall
   have at most a single element. The meaning of `x = {v}`, where `T` is
   the scalar type of the expression `x`, is that of `x = T{v}`. The
   meaning of `x = {}` is `x = T{}`.
 - an assignment to an object of class type, in which case the
   initializer list is passed as the argument to the assignment operator
+  function selected by overload resolution [[over.ass]], [[over.match]].
 [*Example 1*:
 ``` cpp
 complex<double> z;
 [[intro.execution]]. The type and value of the result are the type and
 value of the right operand; the result is of the same value category as
 its right operand, and is a bit-field if its right operand is a
 bit-field.
+[*Note 1*:
+In contexts where the comma token is given special meaning (e.g.,
+function calls [[expr.call]], subscript expressions [[expr.sub]], lists
+of initializers [[dcl.init]], or *template-argument-list*s
+[[temp.names]]), the comma operator as described in this subclause can
+appear only in parentheses.
+[*Example 1*:
 ``` cpp
 f(a, (t=3, t+2), c);
 ```
 has three arguments, the second of which has the value `5`.
 — *end example*]
+— *end note*]

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