[clang] Don't mark lambda non-dependent if nested in a generic lambda. (PR #149121)

[Erich Keane via cfe-commits]

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@@ -15512,6 +15512,8 @@ TreeTransform<Derived>::TransformLambdaExpr(LambdaExpr *E) {
     DC = DC->getParent();
   if ((getSema().isUnevaluatedContext() ||
        getSema().isConstantEvaluatedContext()) &&
+      !(dyn_cast_or_null<CXXRecordDecl>(DC->getParent()) &&
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erichkeane wrote:

We'd want to use `isa_and_present` (or `isa_and_nonnull` or w/e it is called) in this case.

That said, we probably would prefer to do something like extracting above the `if` a `const auto *RD = dyn_cast_if_present<CXXRecordDecl>(DC->getParent());`  then changing the check to RD && RD->isGenericLambda()` (or perhaps BETTER, pulling that whole thing out to a separate boolean with a reasonable name, so you have a place to put a comment).

Which brings me to the last thing, I'd like a comment explaining WHY this check should be here, it looks enough out of place as to why this cannot be dependent.


https://github.com/llvm/llvm-project/pull/149121