72f3f6541b
ail check returns ok for a program that references an unbound identifier inside an instance method's lambda body. The error surfaces later at ail build as a degraded mono-pass diagnostic (monomorphise_workspace: unknown identifier) without source location, symbol kind, or "did you mean" candidates. Cause: check_def at crates/ailang-check/src/lib.rs:1593 early- returns Ok(()) for Def::Instance without walking method bodies. The arm's comment promises instance-body typechecking from iter 22b.2; that wiring was never implemented. Only the workspace- load coherence checks (Orphan/Duplicate/MissingMethod) touch instance defs, and they inspect schema only, not the method- body identifier graph. This commit lands RED only. GREEN follows via implement mini- mode. Fixture: examples/bug_unbound_in_instance_method.ail RED test: crates/ail/tests/unbound_in_instance_method_pin.rs - check_fires_unbound_var_for_str_concat_in_instance_method_body - check_json_unbound_var_in_instance_method_body