[clang] [analyzer] Match dangling subobjects by their base region in DanglingPtrDeref (PR #211552)

[via cfe-commits]

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@@ -112,3 +112,105 @@ void inlined_callee_single_report() {
   // expected-note at -1 {{Calling 'deref_param'}}
   (void)r;
 }
+
+struct MyBuffer {
+  char buffer[8];
+};
+struct MyStruct { int x; };
+struct Inner { int x; };
+struct Outer { struct Inner inner; };
+
+char member_subregion_dangling_deref() {
+  const char *p = nullptr;
+  {
+    struct MyBuffer tmp_buffer = {};
+    p = tmp_buffer.buffer;
+  }
+  // expected-note at -1 {{'tmp_buffer.buffer[0]' is destroyed here}}
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isuckatcs wrote:

What is going to be spelled if `p` is incremented ( `++p`)? Do we track it properly that it now points to `tmp_buffer.buffer[1]`?

https://github.com/llvm/llvm-project/pull/211552