A local function nested in a lambda can capture closures at two depths:
csc emits it as an instance method on the enclosing method's display
class that takes the lambda's display class as a parameter. Combining
those two capture scopes with FindCommonAncestorInstruction picked the
enclosing method, moving the function out of the lambda that owns the
deeper closure; the variables captured there were then unreachable and
the display-class parameter survived into the output as an undeclared
identifier. Nested capture scopes resolve to the innermost instead,
which a local function can always see - it reaches the outer closure
through the display class it is declared on.
Assisted-by: Claude:claude-fable-5:Claude Code
Siegfried Pammer