CS8196 also fires when the second reference sits inside a nested call
in another argument of the declaring call, e.g.
OutAndValue(out var a, UseAndReturn(out a)). The existing check already
covers this because it walks all descendants of the sibling arguments;
this fixture pins that behavior.
Assisted-by: Claude:claude-fable-5:Claude Code
Passing the same local as multiple out arguments of one call made
DeclareVariables turn the first use into an implicitly-typed declaration,
producing 'f(out var x, out x)'. Referencing an implicitly-typed out
variable in another argument of the declaring call is rejected by the
compiler (CS8196), because its type is only inferred once overload
resolution of that call has completed. The explicitly-typed form
'f(out int x, out x)' is valid, so fall back to the explicit type in
that case.
Assisted-by: Claude:claude-fable-5:Claude Code
Record AST transform groups and mutation steps through the C# pipeline, replay selected steps with the stepper, and carry modified-node ranges through output so the Debug Steps pane can highlight the selected mutation without replacing its full step tree.
Assisted-by: CodeAlta:gpt-5.5:CodeAlta