From Jason Turner

[diff.cpp17.dcl.dcl]

C++23 → Trunk 2.7 KB 33 lines
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  1. tmp/tmp8mc07orf/{from.md → to.md} +21 -7
tmp/tmp8mc07orf/{from.md → to.md} RENAMED
@@ -1,23 +1,28 @@
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- ### [[dcl.dcl]]: declarations <a id="diff.cpp17.dcl.dcl">[[diff.cpp17.dcl.dcl]]</a>
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  **Change:** Unnamed classes with a typedef name for linkage purposes can
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  contain only C-compatible constructs. **Rationale:** Necessary for
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  implementability. **Effect on original feature:** Valid C++17 code may
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- be ill-formed in this revision of C++. For example:
 
 
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  ``` cpp
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  typedef struct {
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  void f() {} // ill-formed; previously well-formed
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  } S;
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  ```
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  **Change:** A function cannot have different default arguments in
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  different translation units. **Rationale:** Required for modules
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  support. **Effect on original feature:** Valid C++17 code may be
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- ill-formed in this revision of C++, with no diagnostic required. For
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- example:
 
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  ``` cpp
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  // Translation unit 1
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  int f(int a = 42);
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  int g() { return f(); }
@@ -26,17 +31,20 @@ int g() { return f(); }
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  int f(int a = 76) { return a; } // ill-formed, no diagnostic required; previously well-formed
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  int g();
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  int main() { return g(); } // used to return 42
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  ```
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  **Change:** A class that has user-declared constructors is never an
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  aggregate. **Rationale:** Remove potentially error-prone aggregate
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  initialization which may apply notwithstanding the declared constructors
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  of a class. **Effect on original feature:** Valid C++17 code that
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  aggregate-initializes a type with a user-declared constructor may be
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- ill-formed or have different semantics in this revision of C++. For
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- example:
 
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  ``` cpp
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  struct A { // not an aggregate; previously an aggregate
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  A() = delete;
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  };
@@ -67,14 +75,20 @@ struct Y { // not an aggregate; previously an aggregate
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  };
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  Y y{X{}}; // copy constructor call; previously aggregate-initialization
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  ```
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  **Change:** Boolean conversion from a pointer or pointer-to-member type
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  is now a narrowing conversion. **Rationale:** Catches bugs. **Effect on
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  original feature:** Valid C++17 code may fail to compile in this
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- revision of C++. For example:
 
 
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  ``` cpp
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  bool y[] = { "bc" }; // ill-formed; previously well-formed
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  ```
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+ ### [[dcl]]: declarations <a id="diff.cpp17.dcl.dcl">[[diff.cpp17.dcl.dcl]]</a>
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  **Change:** Unnamed classes with a typedef name for linkage purposes can
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  contain only C-compatible constructs. **Rationale:** Necessary for
5
  implementability. **Effect on original feature:** Valid C++17 code may
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+ be ill-formed in this revision of C++.
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+
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+ [*Example 1*:
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  ``` cpp
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  typedef struct {
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  void f() {} // ill-formed; previously well-formed
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  } S;
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  ```
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+ — *end example*]
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+
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  **Change:** A function cannot have different default arguments in
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  different translation units. **Rationale:** Required for modules
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  support. **Effect on original feature:** Valid C++17 code may be
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+ ill-formed in this revision of C++, with no diagnostic required.
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+
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+ [*Example 2*:
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  ``` cpp
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  // Translation unit 1
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  int f(int a = 42);
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  int g() { return f(); }
 
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  int f(int a = 76) { return a; } // ill-formed, no diagnostic required; previously well-formed
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  int g();
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  int main() { return g(); } // used to return 42
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  ```
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+ — *end example*]
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+
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  **Change:** A class that has user-declared constructors is never an
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  aggregate. **Rationale:** Remove potentially error-prone aggregate
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  initialization which may apply notwithstanding the declared constructors
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  of a class. **Effect on original feature:** Valid C++17 code that
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  aggregate-initializes a type with a user-declared constructor may be
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+ ill-formed or have different semantics in this revision of C++.
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+
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+ [*Example 3*:
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  ``` cpp
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  struct A { // not an aggregate; previously an aggregate
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  A() = delete;
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  };
 
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  };
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  Y y{X{}}; // copy constructor call; previously aggregate-initialization
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  ```
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+ — *end example*]
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+
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  **Change:** Boolean conversion from a pointer or pointer-to-member type
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  is now a narrowing conversion. **Rationale:** Catches bugs. **Effect on
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  original feature:** Valid C++17 code may fail to compile in this
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+ revision of C++.
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+
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+ [*Example 4*:
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  ``` cpp
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  bool y[] = { "bc" }; // ill-formed; previously well-formed
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  ```
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+ — *end example*]
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+