codegen_regression_test.affine

// SPDX-License-Identifier: PMPL-1.0-or-later
// Regression tests for the two AffineScript codegen bugs discovered
// 2026-04-19 and fixed in lib/codegen.ml on the same day:
//
//   1. Enum-in-match stack imbalance — PatCon-with-args left the tag-test
//      boolean on the stack twice, so any match arm whose body produced an
//      i32 value broke WASM validation with "expected 1 elements on the
//      stack for fallthru, found 2". Fixed by removing the redundant
//      LocalTee/LocalGet around the match_result local.
//
//   2. Non-first struct field read from a function parameter returned 0.
//      field_layouts was only populated for let-bound ExprRecord literals,
//      so every other binding path defaulted the offset to 0. Fixed by
//      registering struct layouts globally from TopType(TyStruct) and
//      propagating them to function parameters (via p_ty), call-result
//      lets (via fn_ret_structs), and let-annotated bindings.

enum Lifecycle {
  LUninit,
  LInit,
  LWithProfile(Int),
  LRunning(Int, Int),
  LTerminated
}

struct Counters {
  tag: Int,
  profile_id: Int,
  activity_count: Int
}

fn advance(s: Lifecycle) -> Lifecycle {
  return match s {
    LUninit          => LInit(),
    LInit            => LWithProfile(0),
    LWithProfile(p)  => LRunning(p, 0),
    LRunning(p, c)   => LRunning(p, c + 1),
    LTerminated      => LTerminated()
  };
}

fn make_counters() -> Counters {
  #{ tag: 1, profile_id: 42, activity_count: 7 }
}

fn read_profile_id(c: Counters) -> Int {
  c.profile_id
}

fn read_activity_count(c: Counters) -> Int {
  c.activity_count
}

pub fn test_enum_match_mixed_constructors() -> Bool {
  // Previously: "expected 1 elements on the stack" during instantiate.
  let s0 = LUninit();
  let s1 = advance(s0);
  return true;
}

pub fn test_param_struct_field_offsets() -> Bool {
  // Previously: both helpers returned 0 because field_layouts defaulted
  // the offset. Now the declared `c: Counters` annotation pulls in the
  // struct's layout, so each field reads the right memory slot.
  let c = make_counters();
  return read_profile_id(c) == 42 && read_activity_count(c) == 7;
}

pub fn test_let_from_call_struct_field() -> Bool {
  // Previously: `let c = make_counters()` did not register a layout
  // because RHS wasn't a record literal. Now fn_ret_structs kicks in.
  let c = make_counters();
  return c.activity_count == 7;
}