From Jason Turner

[over.call.object]

C++14 → C++17 4.2 KB 46 lines
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tmp/tmpqeyl502d/{from.md → to.md} RENAMED
@@ -1,30 +1,31 @@
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  ##### Call to object of class type <a id="over.call.object">[[over.call.object]]</a>
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  If the *primary-expression* `E` in the function call syntax evaluates to
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- a class object of type “*cv* `T`”, then the set of candidate functions
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  includes at least the function call operators of `T`. The function call
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  operators of `T` are obtained by ordinary lookup of the name
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  `operator()` in the context of `(E).operator()`.
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  In addition, for each non-explicit conversion function declared in `T`
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  of the form
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  ``` bnf
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- 'operator' conversion-type-id '( )' cv-qualifier ref-qualifierₒₚₜ exception-specificationₒₚₜ attribute-specifier-seqₒₚₜ ';'
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  ```
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  where *cv-qualifier* is the same cv-qualification as, or a greater
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- cv-qualification than, *cv*, and where *conversion-type-id* denotes the
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- type “pointer to function of (`P1`,...,`Pn)` returning `R`”, or the type
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- “reference to pointer to function of (`P1`,...,`Pn)` returning `R`”, or
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- the type “reference to function of (`P1`,...,`Pn)` returning `R`”, a
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  *surrogate call function* with the unique name *call-function* and
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  having the form
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  ``` bnf
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- 'R' call-function '(' conversion-type-id 'F, P1 a1, ... ,Pn an)' '{ return F (a1,... ,an); }'
 
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  ```
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  is also considered as a candidate function. Similarly, surrogate call
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  functions are added to the set of candidate functions for each
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  non-explicit conversion function declared in a base class of `T`
@@ -38,28 +39,33 @@ then be invoked with the arguments of the call. If the conversion
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  function cannot be called (e.g., because of an ambiguity), the program
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  is ill-formed.
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  The argument list submitted to overload resolution consists of the
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  argument expressions present in the function call syntax preceded by the
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- implied object argument `(E)`. When comparing the call against the
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- function call operators, the implied object argument is compared against
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- the implicit object parameter of the function call operator. When
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- comparing the call against a surrogate call function, the implied object
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- argument is compared against the first parameter of the surrogate call
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- function. The conversion function from which the surrogate call function
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- was derived will be used in the conversion sequence for that parameter
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- since it converts the implied object argument to the appropriate
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- function pointer or reference required by that first parameter.
 
 
 
 
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  ``` cpp
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  int f1(int);
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  int f2(float);
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  typedef int (*fp1)(int);
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  typedef int (*fp2)(float);
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  struct A {
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  operator fp1() { return f1; }
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  operator fp2() { return f2; }
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  } a;
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- int i = a(1); // calls f1 via pointer returned from
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- // conversion function
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  ```
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  ##### Call to object of class type <a id="over.call.object">[[over.call.object]]</a>
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  If the *primary-expression* `E` in the function call syntax evaluates to
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+ a class object of type “cv `T`”, then the set of candidate functions
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  includes at least the function call operators of `T`. The function call
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  operators of `T` are obtained by ordinary lookup of the name
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  `operator()` in the context of `(E).operator()`.
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  In addition, for each non-explicit conversion function declared in `T`
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  of the form
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  ``` bnf
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+ 'operator' conversion-type-id '( )' cv-qualifier ref-qualifierₒₚₜ noexcept-specifierₒₚₜ attribute-specifier-seqₒₚₜ ';'
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  ```
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  where *cv-qualifier* is the same cv-qualification as, or a greater
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+ cv-qualification than, cv, and where *conversion-type-id* denotes the
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+ type “pointer to function of (`P₁`, …, `Pₙ`) returning `R`”, or the type
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+ “reference to pointer to function of (`P₁`, …, `Pₙ`) returning `R`”, or
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+ the type “reference to function of (`P₁`, …, `Pₙ`) returning `R`”, a
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  *surrogate call function* with the unique name *call-function* and
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  having the form
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  ``` bnf
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+ 'R' call-function '(' conversion-type-id \ %
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+ 'F, P₁ a₁, …, Pₙ aₙ)' '{ return F (a₁, …, aₙ); }'
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  ```
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  is also considered as a candidate function. Similarly, surrogate call
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  functions are added to the set of candidate functions for each
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  non-explicit conversion function declared in a base class of `T`
 
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  function cannot be called (e.g., because of an ambiguity), the program
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  is ill-formed.
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  The argument list submitted to overload resolution consists of the
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  argument expressions present in the function call syntax preceded by the
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+ implied object argument `(E)`.
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+
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+ [*Note 2*: When comparing the call against the function call operators,
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+ the implied object argument is compared against the implicit object
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+ parameter of the function call operator. When comparing the call against
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+ a surrogate call function, the implied object argument is compared
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+ against the first parameter of the surrogate call function. The
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+ conversion function from which the surrogate call function was derived
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+ will be used in the conversion sequence for that parameter since it
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+ converts the implied object argument to the appropriate function pointer
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+ or reference required by that first parameter. — *end note*]
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+
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+ [*Example 1*:
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  ``` cpp
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  int f1(int);
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  int f2(float);
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  typedef int (*fp1)(int);
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  typedef int (*fp2)(float);
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  struct A {
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  operator fp1() { return f1; }
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  operator fp2() { return f2; }
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  } a;
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+ int i = a(1); // calls f1 via pointer returned from conversion function
 
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  ```
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+ — *end example*]
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+