Nine tasks: Emitter struct extension with mut_var_allocas +
pending_entry_allocas + entry_block_end_marker fields (Task 1);
start_block captures the entry-block byte marker (Task 2);
Term::Var resolution prepends mut-var lookup with load emission
(Task 3); Term::Mut codegen — alloca to side buffer, init at
current position, store to alloca, push binding (Task 4);
Term::Assign codegen — load alloca, lower value, store (Task 5);
final flush of pending_entry_allocas into self.body at the marker
(Task 6); examples/mut_counter.ail (Int) + examples/mut_sum_floats.ail
(Float) (Task 7); e2e tests in crates/ail/tests/e2e.rs (Task 8);
DESIGN.md bullet under 'What is supported' (Task 9).
Five Boss decisions encoded: entry-block hoist via String::insert_str
at the captured marker (chosen over post-pass or non-standard
emit-at-current); no LLVM helper wrapper — direct push_str matches
existing codebase convention; e2e tests append to the existing
crates/ail/tests/e2e.rs (reuse build_and_run helper); DESIGN.md
bullet lives in 'What is supported' subsection (recon misread —
the section exists at line 2680); Unit-codegen via the existing
Term::Lit { lit: Unit } canonical form.
Brummel
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