[clang] [clang][dataflow] Model the fields that are accessed via inline accessors (PR #66368)

[via cfe-commits]

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@@ -288,6 +288,18 @@ static void insertIfFunction(const Decl &D,
     Funcs.insert(FD);
 }
 
+static Expr *getRetValueFromSingleReturnStmtMethod(const CXXMemberCallExpr &C) {
+  auto *D = cast_or_null<CXXMethodDecl>(C.getMethodDecl()->getDefinition());
+  if (!D)
+    return nullptr;
+  auto *S = cast<CompoundStmt>(D->getBody());
+  if (S->size() != 1)
+    return nullptr;
+  if (auto *RS = dyn_cast<ReturnStmt>(*S->body_begin()))
+    return RS->getRetValue()->IgnoreParenImpCasts();
+  return nullptr;
----------------
martinboehme wrote:

```suggestion
  auto *Body = dyn_cast<CompoundStmt>(C.getBody());
  if (!Body || Body->size() != 1)
    return nullptr;
  if (auto *RS = dyn_cast<ReturnStmt>(*Body->body_begin()))
    return RS->getRetValue()->IgnoreParenImpCasts();
  return nullptr;
```

- `getBody()` can be called on any declaration, not just the definition
- Suggest renaming `S` to `Body` for clarity
- The fact that `getBody()` returns just a `Stmt *` makes me wary that casting unconditionally to `CompoundStmt` may not be safe, so suggest using `dyn_cast` instead.

https://github.com/llvm/llvm-project/pull/66368