[clang] __is_trivially_equality_comparable should return false for arrays

[philnik]

Summary

When comparing two arrays, their pointers are compared instead of their elements, which means that they are not trivially equality comparable

Fixes #63371

[cor3ntin]

s/menas/means/ in the commit message.

Otherwise LGTM

clang/lib/AST/Type.cpp

return llvm::all_of(Decl->bases(),
            return true;
          });
 }
 
 bool QualType::isTriviallyEqualityComparableType(
     const ASTContext &Context) const {
   QualType CanonicalType = getCanonicalType();
   if (CanonicalType->isIncompleteType() || CanonicalType->isDependentType() ||
-      CanonicalType->isEnumeralType())
+      CanonicalType->isEnumeralType() || CanonicalType->isArrayType())
     return false;
 
   if (const auto *RD = CanonicalType->getAsCXXRecordDecl()) {
     if (!HasNonDeletedDefaultedEqualityComparison(RD))
       return false;
   }
 
   return Context.hasUniqueObjectRepresentations(

clang/test/SemaCXX/type-traits.cpp

 
 namespace is_trivially_equality_comparable {
 struct ForwardDeclared; // expected-note {{forward declaration of 'is_trivially_equality_comparable::ForwardDeclared'}}
 static_assert(!__is_trivially_equality_comparable(ForwardDeclared), ""); // expected-error {{incomplete type 'ForwardDeclared' used in type trait expression}}
 
 static_assert(!__is_trivially_equality_comparable(void), "");
 static_assert(__is_trivially_equality_comparable(int), "");
 static_assert(!__is_trivially_equality_comparable(int[]), "");
-static_assert(__is_trivially_equality_comparable(int[3]), "");
+static_assert(!__is_trivially_equality_comparable(int[3]), "");
 static_assert(!__is_trivially_equality_comparable(float), "");
 static_assert(!__is_trivially_equality_comparable(double), "");
 static_assert(!__is_trivially_equality_comparable(long double), "");
 
 struct TriviallyEqualityComparableNoDefaultedComparator {
   int i;
   int j;
 };
 static_assert(!__is_trivially_equality_comparable(TriviallyEqualityComparableNoDefaultedComparator), "");
 
 #if __cplusplus >= 202002L
 
 struct TriviallyEqualityComparable {
   int i;
   int j;
 
   void func();
   bool operator==(int) const { return false; }
 
   bool operator==(const TriviallyEqualityComparable&) const = default;
 };
 static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparable), "");
 
+struct TriviallyEqualityComparableContainsArray {
+  int a[4];
+
+  bool operator==(const TriviallyEqualityComparableContainsArray&) const = default;
+};
+static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableContainsArray));
+
 struct TriviallyEqualityComparableNonTriviallyCopyable {
   TriviallyEqualityComparableNonTriviallyCopyable(const TriviallyEqualityComparableNonTriviallyCopyable&);
   ~TriviallyEqualityComparableNonTriviallyCopyable();
   bool operator==(const TriviallyEqualityComparableNonTriviallyCopyable&) const = default;
   int i;
 };
 static_assert(__is_trivially_equality_comparable(TriviallyEqualityComparableNonTriviallyCopyable));