[clang] [NFC][analyzer] Spread use of 'Expr*' instead of 'Stmt*' (PR #188319)

[Balázs Benics via cfe-commits]

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@@ -32,6 +32,12 @@ class SymbolReaper;
 /// This allows the environment to manage context-sensitive bindings,
 /// which is essentially for modeling recursive function analysis, among
 /// other things.
+/// FIXME: Use 'Expr' instead of 'Stmt' because associating a result with a
+/// non-expression statement does not make sense. Currently the environment
+/// never contains non-expression statements; and there is only one
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steakhal wrote:

I'm tempted to simplify the double negation with saying `the environment only contains Exprs`

https://github.com/llvm/llvm-project/pull/188319