[llvm] [ADT] Fix llvm::concat_iterator for `ValueT == common_base_class *` (PR #144744)

[Jakub Kuderski via llvm-commits]

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@@ -532,6 +534,21 @@ TEST(STLExtrasTest, ConcatRangeADL) {
   EXPECT_THAT(concat<const int>(S0, S1), ElementsAre(1, 2, 3, 4));
 }
 
+TEST(STLExtrasTest, ConcatRangePtrToDerivedClass) {
+  auto S0 = std::make_unique<some_namespace::some_struct>();
+  auto S1 = std::make_unique<some_namespace::derives_from_some_struct>();
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kuhar wrote:

I don't think we necessarily need unique_ptr to test this, stack allocated values would work too.

https://github.com/llvm/llvm-project/pull/144744