tmp/tmpw4vp4c98/{from.md → to.md}
RENAMED
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| 1 |
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### [[expr]]: expressions <a id="diff.cpp23.expr">[[diff.cpp23.expr]]</a>
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**Change:** Operations mixing a value of an enumeration type and a value
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of a different enumeration type or of a floating-point type are no
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longer valid. **Rationale:** Reinforcing type safety. **Effect on
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original feature:** A valid C++23 program that performs operations
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mixing a value of an enumeration type and a value of a different
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enumeration type or of a floating-point type is ill-formed.
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[*Example 1*:
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``` cpp
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enum E1 { e };
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enum E2 { f };
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bool b = e <= 3.7; // ill-formed; previously well-formed
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int k = f - e; // ill-formed; previously well-formed
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auto x = true ? e : f; // ill-formed; previously well-formed
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```
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— *end example*]
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**Change:** Comparing two objects of array type is no longer valid.
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**Rationale:** The old behavior was confusing since it compared not the
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contents of the two arrays, but their addresses. **Effect on original
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feature:** A valid C++23 program directly comparing two array objects is
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rejected as ill-formed in this document.
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[*Example 2*:
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``` cpp
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int arr1[5];
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int arr2[5];
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bool same = arr1 == arr2; // ill-formed; previously well-formed
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bool idem = arr1 == +arr2; // compare addresses
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bool less = arr1 < +arr2; // compare addresses, unspecified result
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```
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— *end example*]
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**Change:** Calling `delete` on a pointer to an incomplete class is
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ill-formed. **Rationale:** Reduce undefined behavior. **Effect on
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original feature:** A valid C++23 program that calls `delete` on an
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incomplete class type is ill-formed.
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[*Example 3*:
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``` cpp
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struct S;
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void f(S *p) {
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delete p; // ill-formed; previously well-formed
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}
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struct S {};
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```
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— *end example*]
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