[clang] [clang][dataflow] Add synthetic fields to `RecordStorageLocation` (PR #73860)

[Yitzhak Mandelbaum via cfe-commits]

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@@ -73,7 +73,13 @@ class ScalarStorageLocation final : public StorageLocation {
 ///
 /// Contains storage locations for all modeled fields of the record (also
 /// referred to as "children"). The child map is flat, so accessible members of
-/// the base class are directly accesible as children of this location.
+/// the base class are directly accessible as children of this location.
+///
+/// Record storage locations may also contain so-called synthetic fields. These
+/// are typically used to the internal state of a class (e.g. the value stored
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ymand wrote:

"used to model"?

https://github.com/llvm/llvm-project/pull/73860