[clang] [Clang] make most enums trivially equality comparable (PR #169079)

[via cfe-commits]

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@@ -4321,6 +4305,38 @@ struct TriviallyEqualityComparable {
 };
 static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparable));
 
+template <class T>
+struct TriviallyEqualityComparableContains {
+  T t;
+
+  friend bool operator==(const TriviallyEqualityComparableContains&, const TriviallyEqualityComparableContains&) = default;
+};
+
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContains<int>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<int&>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<float>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<double>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<long double>));
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContains<int[4]>));
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContains<int[4][4]>));
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContains<Enum>));
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContains<Enum[2]>));
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContains<Enum[2][2]>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<EnumWithOpEq>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<EnumWithOpEq[2]>));
+static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableContains<EnumWithOpEq[2][2]>));
+
+auto GetNonCapturingLambda() { return [](){ return 42; }; }
+
+struct TriviallyEqualityComparableContainsLambda {
+  [[no_unique_address]] decltype(GetNonCapturingLambda()) l;
+  int i;
+
+  friend bool operator==(const TriviallyEqualityComparableContainsLambda&, const TriviallyEqualityComparableContainsLambda&) = default;
+};
+static_assert(!__is_trivially_equality_comparable(decltype(GetNonCapturingLambda()))); // padding
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContainsLambda));
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halbi2 wrote:

ok, please land it now

https://github.com/llvm/llvm-project/pull/169079