[clang] [Clang] Added explanation why a is trivial copyable evaluated to false. (PR #142341)

[Shamshura Egor via cfe-commits]

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@@ -144,3 +144,54 @@ static_assert(__builtin_is_cpp_trivially_relocatable(U2));
 // expected-note@#tr-U2 {{'U2' defined here}}
 
 }
+
+namespace trivially_copyable {
+struct B {
+ virtual ~B();
+};
+struct S : virtual B { // #tc-S
+    S();
+    int & a;
+    const int ci;
+    B & b;
+    B c;
+    ~S();
+};
+static_assert(__is_trivially_copyable(S));
+// expected-error at -1 {{static assertion failed due to requirement '__is_trivially_copyable(trivially_copyable::S)'}} \
+// expected-note at -1 {{'S' is not trivially copyable}} \
+// expected-note at -1 {{because it has a virtual base 'B'}} \
+// expected-note at -1 {{because it has a non-trivially-copyable base 'B'}} \
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egorshamshura wrote:

Added some tests for this case

https://github.com/llvm/llvm-project/pull/142341