Module: MilkTea::LowererBlock

Included in:
Lowerer
Defined in:
lib/milk_tea/core/lowering/block.rb

Instance Method Summary collapse

Instance Method Details

#dereference_if_self_ref(field_expr, field_type, scrutinee_type) ⇒ Object 



370
371
372
373
374
375
376
 
# File 'lib/milk_tea/core/lowering/block.rb', line 370

def dereference_if_self_ref(field_expr, field_type, scrutinee_type)
  if variant_self_referencing_field?(field_type, scrutinee_type)
    IR::Unary.new(operator: "*", operand: field_expr, type: field_type)
  else
    field_expr
  end
end

#inline_loop_element_type(element) ⇒ Object 



258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
 
# File 'lib/milk_tea/core/lowering/block.rb', line 258

def inline_loop_element_type(element)
  if element.is_a?(Types::FieldHandle)
    @ctx.types.fetch("field_handle")
  elsif element.is_a?(Types::CallableHandle)
    @ctx.types.fetch("callable_handle")
  elsif element.is_a?(Types::AttributeHandle)
    @ctx.types.fetch("attribute_handle")
  elsif element.is_a?(Types::MemberHandle)
    @ctx.types.fetch("member_handle")
  elsif element.is_a?(Types::StructHandle)
    @ctx.types.fetch("struct_handle")
  else
    @ctx.types.fetch("int")
  end
end

#lower_block(statements, env:, active_defers:, return_type:, loop_flow:, allow_return: true) ⇒ Object 



5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
 
# File 'lib/milk_tea/core/lowering/block.rb', line 5

def lower_block(statements, env:, active_defers:, return_type:, loop_flow:, allow_return: true)
  local_env = duplicate_env(env)
  lowered = []
  local_defers = []
  local_env[:return_context] = {
    return_type:,
    active_defers:,
    local_defers:,
    allow_return:,
  }

  statements.each do |statement|
    case statement
    when AST::DeferStmt
      local_defers << if statement.body
        lower_defer_cleanup_body(statement.body, env: local_env, return_type:)
      else
        lower_defer_cleanup_expression(statement.expression, env: local_env)
      end
    when AST::UnsafeStmt
      lower_block_unsafe_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    when AST::LocalDecl
      lower_block_local_decl_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    when AST::Assignment
      lower_block_assignment_stmt(statement, lowered:, local_defers:, local_env:)
    when AST::IfStmt
      lower_block_if_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    when AST::MatchStmt
      lower_block_match_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    when AST::StaticAssert
      lowered << lower_static_assert(statement, env: local_env)
    when AST::ForStmt
      if statement.inline
        lowered.concat(lower_inline_for_stmt(statement, env: local_env, active_defers:, return_type:, allow_return:))
      else
        lowered << lower_for_stmt(statement, env: local_env, active_defers: active_defers + local_defers, return_type:, allow_return:)
      end
    when AST::ParallelBlockStmt
      lowered << lower_parallel_block_stmt(statement, env: local_env, active_defers: active_defers + local_defers)
    when AST::GatherStmt
      lowered << lower_gather_stmt(statement, env: local_env)
    when AST::WhileStmt
      if statement.inline
        lowered.concat(lower_inline_while_stmt(statement, env: local_env, active_defers:, return_type:, allow_return:))
      else
        lowered << lower_while_stmt(statement, env: local_env, active_defers: active_defers + local_defers, return_type:, allow_return:)
      end
    when AST::PassStmt
      nil
    when AST::BreakStmt
      raise LoweringError.new("break must be inside a loop",
        line: statement.line, column: statement.column, path: @ctx.current_analysis_path) unless loop_flow

      lowered.concat(lower_loop_exit(loop_flow[:break_target], local_defers, loop_flow[:break_defers]))
    when AST::ContinueStmt
      raise LoweringError.new("continue must be inside a loop",
        line: statement.line, column: statement.column, path: @ctx.current_analysis_path) unless loop_flow

      lowered.concat(lower_loop_exit(loop_flow[:continue_target], local_defers, loop_flow[:continue_defers]))
    when AST::ReturnStmt
      lower_block_return_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, allow_return:)
    when AST::ExpressionStmt
      lower_block_expression_stmt(statement, lowered:, local_defers:, local_env:)
    when AST::EmitStmt
      lowered.concat(lower_emit_stmt(statement, env: local_env))
    when AST::WhenStmt
      lower_block_when_stmt(statement, lowered:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    else
      raise LoweringError.new("unsupported statement #{statement.class.name}",
        line: statement.line, column: statement.column, path: @ctx.current_analysis_path)
    end
  end

  unless terminating_ir_statement?(lowered.last)
    lowered.concat(cleanup_statements(local_defers, []))
  end
  lowered
end

#lower_block_assignment_stmt(statement, lowered:, local_defers:, local_env:) ⇒ Object 



504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
 
# File 'lib/milk_tea/core/lowering/block.rb', line 504

def lower_block_assignment_stmt(statement, lowered:, local_defers:, local_env:)
  if statement.operator == "=" &&
     statement.target.is_a?(AST::IndexAccess) &&
     statement.target.index.is_a?(AST::RangeExpr) &&
     statement.value.is_a?(AST::ExpressionList)
    lowered.concat(lower_range_index_assignment(statement, env: local_env))
    return
  end
  target = lower_assignment_target(statement.target, env: local_env)
  prepared_cleanups = []
  prepared_setup, prepared_value, prepared_cleanups = prepare_expression_with_cleanups(
    statement.value,
    env: local_env,
    expected_type: target.type,
    allow_root_statement_foreign: true,
    materialize_array_calls: !array_type?(target.type),
  )
  lowered.concat(prepared_setup)
  if (foreign_call = foreign_call_info(prepared_value, local_env))
    setup, value, call_type, release_assignments, cleanup_statements = lower_foreign_call_components(
      foreign_call,
      env: local_env,
      expected_type: target.type,
      statement_position: false,
    )
    lowered.concat(setup)
    raise LoweringError.new("foreign call used in assignment must return a value",
      line: statement.line, column: statement.column, path: @ctx.current_analysis_path) if call_type == @ctx.types.fetch("void")
    raise LoweringError.new("consuming foreign calls must return void",
      line: statement.line, column: statement.column, path: @ctx.current_analysis_path) unless release_assignments.empty?

    lowered << IR::Assignment.new(target:, operator: statement.operator, value:)
    lowered.concat(cleanup_statements)
    update_cstr_metadata_for_assignment!(statement, prepared_value, local_env)
    local_defers.concat(suppress_format_releases_for_assignment(prepared_cleanups, target.type))
    return
  else
    value = if statement.operator == "="
      lower_contextual_expression(
        prepared_value,
        env: local_env,
        expected_type: target.type,
        external_numeric: external_numeric_assignment_target?(statement.target, env: local_env),
        contextual_int_to_float: contextual_int_to_float_target?(target.type),
      )
    elsif ["+=", "-=", "*=", "/="].include?(statement.operator)
      lower_contextual_expression(
        prepared_value,
        env: local_env,
        expected_type: target.type,
        contextual_int_to_float: contextual_int_to_float_target?(target.type),
      )
    else
      lower_expression(prepared_value, env: local_env, expected_type: target.type)
    end
  end
  if target.type.is_a?(Types::Nullable) && value && !value.type.is_a?(Types::Nullable) && !pointer_like_type?(target.type.base)
    value = nullable_some_literal(target.type, value)
  end
  update_cstr_metadata_for_assignment!(statement, prepared_value, local_env)
  local_defers.concat(suppress_format_releases_for_assignment(prepared_cleanups, target.type))
  operator = statement.operator
  if ["+=", "-=", "*=", "/="].include?(operator) &&
     (target.type.is_a?(Types::Vector) || target.type.is_a?(Types::Matrix) || target.type.is_a?(Types::Quaternion))
    binary_op = operator[0...-1]
    expanded = lower_vector_binary_op(binary_op, target, target.type, value, value.type, target.type)
    value = expanded || IR::Binary.new(operator: binary_op, left: target, right: value, type: target.type)
    operator = "="
  end
  if operator == "=" && contains_proc_storage_type?(target.type)
    rhs_name = fresh_c_temp_name(local_env, "proc_assign")
    lowered << IR::LocalDecl.new(name: rhs_name, linkage_name: rhs_name, type: target.type, value:)
    rhs = IR::Name.new(name: rhs_name, type: target.type, pointer: false)
    lowered.concat(lower_proc_selective_retain_statements(rhs, statement.value, target.type))
    lowered.concat(lower_proc_contained_guarded_release_statements(target, target.type))
    lowered << IR::Assignment.new(target:, operator: "=", value: rhs)
  else
    lowered << IR::Assignment.new(target:, operator:, value:)
  end
end

#lower_block_expression_stmt(statement, lowered:, local_defers:, local_env:) ⇒ Object 



417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
 
# File 'lib/milk_tea/core/lowering/block.rb', line 417

def lower_block_expression_stmt(statement, lowered:, local_defers:, local_env:)
  if (format_sink_statements = lower_explicit_format_sink_expression_statement(statement.expression, env: local_env, line: statement.line))
    lowered.concat(format_sink_statements)
    return
  end

  expression_expected_type = if statement.expression.is_a?(AST::UnaryOp) && statement.expression.operator == "?"
    nil
  else
    infer_expression_type(statement.expression, env: local_env)
  end
  prepared_setup, prepared_expression, prepared_cleanups = prepare_expression_with_cleanups(
    statement.expression,
    env: local_env,
    expected_type: expression_expected_type,
    allow_root_statement_foreign: true,
    allow_void_propagation: true,
  )
  lowered.concat(prepared_setup)
  if prepared_expression && (foreign_call = foreign_call_info(prepared_expression, local_env))
    setup, _value = lower_foreign_call_statement(
      foreign_call,
      env: local_env,
      expected_type: foreign_call[:binding].type.return_type,
      statement_position: true,
      discard_result: true,
    )
    lowered.concat(setup)
    lowered.concat(prepared_cleanups.flat_map(&:itself))
    local_env[:scopes] = scopes_with_refinements(local_env[:scopes], consuming_foreign_call_refinements(foreign_call, local_env))
  elsif prepared_expression
    lowered << IR::ExpressionStmt.new(expression: lower_expression(prepared_expression, env: local_env), line: statement.line, path: @ctx.current_analysis_path)
    lowered.concat(prepared_cleanups.flat_map(&:itself))
  else
    lowered.concat(prepared_cleanups.flat_map(&:itself))
  end
end

#lower_block_if_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
 
# File 'lib/milk_tea/core/lowering/block.rb', line 585

def lower_block_if_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  if statement.inline
    lowered.concat(lower_inline_if_stmt(statement, env: local_env, active_defers:, return_type:, allow_return:))
    return
  end

  false_refinements = {}
  branch_entries = []

  unless statement.branches.empty?
    if @bypass_sema_type_cache
      ct_cond = compile_time_const_value(statement.branches.first.condition, env: local_env)
      if ct_cond == true
        lowered.concat(lower_block(
          statement.branches.first.body,
          env: local_env,
          active_defers: active_defers + local_defers,
          return_type:,
          loop_flow: nested_loop_flow(loop_flow, local_defers),
          allow_return:,
        ))
        return
      elsif ct_cond == false
        if statement.else_body
          lowered.concat(lower_block(
            statement.else_body,
            env: local_env,
            active_defers: active_defers + local_defers,
            return_type:,
            loop_flow: nested_loop_flow(loop_flow, local_defers),
            allow_return:,
          ))
        end
        return
      end
    end
  end

  statement.branches.each do |branch|
    branch_env = env_with_refinements(local_env, false_refinements)
    condition_setup, prepared_condition, condition_cleanups = prepare_expression_with_cleanups(
      branch.condition,
      env: branch_env,
      expected_type: @ctx.types.fetch("bool"),
    )
    true_refinements = merge_refinements(false_refinements, flow_refinements(branch.condition, truthy: true, env: branch_env))

    branch_entries << [
      condition_setup,
      condition_cleanups,
      lower_expression(prepared_condition, env: branch_env, expected_type: @ctx.types.fetch("bool")),
      lower_block(
        branch.body,
        env: env_with_refinements(local_env, true_refinements),
        active_defers: active_defers + local_defers,
        return_type:,
        loop_flow: nested_loop_flow(loop_flow, local_defers),
        allow_return:,
      ),
    ]

    false_refinements = merge_refinements(false_refinements, flow_refinements(branch.condition, truthy: false, env: branch_env))
  end

  nested_else_body = statement.else_body ? lower_block(
    statement.else_body,
    env: env_with_refinements(local_env, false_refinements),
    active_defers: active_defers + local_defers,
    return_type:,
    loop_flow: nested_loop_flow(loop_flow, local_defers),
    allow_return:,
  ) : []

  nested_if = nested_else_body
  branch_entries.reverse_each do |condition_setup, condition_cleanups, condition, then_body|
    condition_cleanup_statements = condition_cleanups.flat_map(&:itself)
    nested_if = [
      *condition_setup,
      IR::IfStmt.new(
        condition:,
        then_body: condition_cleanup_statements + then_body,
        else_body: condition_cleanup_statements + nested_if,
      ),
    ]
  end
  lowered.concat(nested_if)

  merge_cstr_metadata_after_if_statement!(statement, local_env)

  if statement.else_body.nil? && statement.branches.all? { |branch| cfg_block_always_terminates?(branch.body) }
    local_env[:scopes] = scopes_with_refinements(local_env[:scopes], false_refinements)
  end
end

#lower_block_local_decl_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
 
# File 'lib/milk_tea/core/lowering/block.rb', line 679

def lower_block_local_decl_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  if statement.destructure_bindings
    lower_destructure_decl(statement, env: local_env, lowered:, local_defers:, active_defers:, return_type:, loop_flow:, allow_return:)
    return
  end

  storage_type = if statement.else_body
    infer_expression_type(statement.value, env: local_env)
  elsif statement.type
    resolve_type_ref(statement.type)
  else
    infer_expression_type(statement.value, env: local_env)
  end
  type = if statement.else_body
    statement.type ? resolve_type_ref(statement.type) : let_else_success_type(storage_type)
  else
    storage_type
  end
  linkage_name = let_else_storage_c_name(statement, local_env)
  decl_name = bind_let_else_local?(statement) ? statement.name : linkage_name
  prepared_setup = []
  prepared_value = statement.value
  prepared_cleanups = []
  emitted_decl = false
  if statement.value
    local_env[:current_local_name] = linkage_name
    prepared_setup, prepared_value, prepared_cleanups = prepare_expression_with_cleanups(
      statement.value,
      env: local_env,
      expected_type: storage_type,
      allow_root_statement_foreign: true,
      materialize_array_calls: !array_type?(storage_type),
    )
    lowered.concat(prepared_setup)
  end
  if prepared_value && (foreign_call = foreign_call_info(prepared_value, local_env))
    setup, value, call_type, release_assignments, cleanup_statements = lower_foreign_call_components(
      foreign_call,
      env: local_env,
      expected_type: storage_type,
      statement_position: false,
    )
    lowered.concat(setup)
    raise LoweringError.new("foreign call used to initialize #{statement.name} must return a value",
      line: statement.line, column: statement.column, path: @ctx.current_analysis_path) if call_type == @ctx.types.fetch("void")
    raise LoweringError.new("consuming foreign calls must return void",
      line: statement.line, column: statement.column, path: @ctx.current_analysis_path) unless release_assignments.empty?

    lowered << IR::LocalDecl.new(name: decl_name, linkage_name:, type: storage_type, value:, line: statement.line, path: @ctx.current_analysis_path)
    lowered.concat(cleanup_statements)
    emitted_decl = true
  elsif prepared_value.is_a?(AST::ProcExpr)
    setup, value = lower_proc_expression_for_local(prepared_value, env: local_env, local_name: statement.name, proc_type: storage_type)
    lowered.concat(setup)
  elsif prepared_value
    value = lower_contextual_expression(
      prepared_value,
      env: local_env,
      expected_type: storage_type,
      contextual_int_to_float: statement.type && contextual_int_to_float_target?(type),
    )
  else
    value = IR::ZeroInit.new(type: storage_type)
  end
  if value && storage_type.is_a?(Types::Nullable) && !value.type.is_a?(Types::Nullable) && !pointer_like_type?(storage_type.base)
    value = nullable_some_literal(storage_type, value)
  end
  if bind_let_else_local?(statement)
    current_actual_scope(local_env[:scopes])[statement.name] = local_binding(
      type:,
      storage_type:,
      linkage_name:,
      mutable: statement.kind == :var,
      pointer: false,
      projection: statement.else_body ? let_else_binding_projection(storage_type) : nil,
      cstr_backed: cstr_backed_storage_value?(storage_type, prepared_value, local_env),
      cstr_list_backed: cstr_list_backed_storage_value?(storage_type, prepared_value, local_env),
      const_value: statement.else_body ? nil : statement.kind == :let && prepared_value ? compile_time_const_value(prepared_value, env: local_env) : nil,
    )
  end
  lowered << IR::LocalDecl.new(name: decl_name, linkage_name:, type: storage_type, value:, line: statement.line, path: @ctx.current_analysis_path) unless emitted_decl
  if statement.else_body
    else_env = if statement.else_binding
      duplicate_env(local_env).tap do |env_with_error|
        current_actual_scope(env_with_error[:scopes])[statement.else_binding.name] = local_binding(
          type: let_else_error_type(storage_type),
          storage_type:,
          linkage_name:,
          mutable: false,
          pointer: false,
          projection: :result_failure_error,
        )
      end
    else
      local_env
    end
    else_body = lower_block(
      statement.else_body,
      env: else_env,
      active_defers: active_defers + local_defers + prepared_cleanups,
      return_type:,
      loop_flow: nested_loop_flow(loop_flow, local_defers),
      allow_return:,
    )
    local_ref = IR::Name.new(name: linkage_name, type: storage_type, pointer: false)
    lowered << IR::IfStmt.new(
      condition: let_else_failure_condition(local_ref, storage_type),
      then_body: else_body,
      else_body: nil,
    )
  end
  local_defers.concat(prepared_cleanups)
  if contains_proc_storage_type?(storage_type)
    local_value = IR::Name.new(name: linkage_name, type: storage_type, pointer: false)
    local_defers << lower_proc_contained_guarded_release_statements(local_value, storage_type)
    if statement.value && !expression_contains_proc_expr?(statement.value)
      lowered.concat(lower_proc_contained_retain_statements(local_value, storage_type))
    end
  end
end

#lower_block_match_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
 
# File 'lib/milk_tea/core/lowering/block.rb', line 800

def lower_block_match_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  if statement.inline
    lowered.concat(lower_inline_match_stmt(statement, env: local_env, active_defers:, return_type:, allow_return:))
    return
  end
  scrutinee_type = infer_expression_type(statement.expression, env: local_env)
  expression_setup, prepared_expression, expression_cleanups = prepare_expression_with_cleanups(
    statement.expression,
    env: local_env,
    expected_type: scrutinee_type,
  )
  lowered.concat(expression_setup)
  expression = lower_expression(prepared_expression, env: local_env, expected_type: scrutinee_type)

  if scrutinee_type.is_a?(Types::Variant) &&
     statement.arms.any? { |arm| arm.binding_name && !wildcard_arm_pattern?(arm.pattern) } &&
     !duplicable_foreign_argument_expression?(expression)
    scrutinee_linkage_name = fresh_c_temp_name(local_env, "match_value")
    lowered << IR::LocalDecl.new(name: scrutinee_linkage_name, linkage_name: scrutinee_linkage_name, type: scrutinee_type, value: expression)
    expression = IR::Name.new(name: scrutinee_linkage_name, type: scrutinee_type, pointer: false)
  end

  if scrutinee_type.is_a?(Types::Variant)
    if statement.arms.any? { |arm| arm.pattern.is_a?(AST::Call) }
      lower_block_variant_struct_pattern_match(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    else
      kind_type = @ctx.types.fetch("int")
      kind_expr = IR::Member.new(receiver: expression, member: "kind", type: kind_type)
      arm_loop_flow = switch_loop_flow(loop_flow, local_defers)
      cases = statement.arms.map do |arm|
        arm_local_env = duplicate_env(local_env)
        binding_decl = if arm.binding_name && !wildcard_arm_pattern?(arm.pattern)
          arm_name = variant_match_arm_name_from_pattern(arm.pattern)
          if arm_name && scrutinee_type.has_payload?(arm_name)
            fields = scrutinee_type.arm(arm_name)
            payload_type = Types::VariantArmPayload.new(scrutinee_type, arm_name, fields)
            data_expr = IR::Member.new(receiver: expression, member: "data", type: nil)
            arm_expr = IR::Member.new(receiver: data_expr, member: arm_name, type: payload_type)
            binding_c = c_local_name(arm.binding_name)
            arm_local_env[:scopes].last[arm.binding_name] = local_binding(type: payload_type, linkage_name: binding_c, mutable: true, pointer: false)
            IR::LocalDecl.new(name: arm.binding_name, linkage_name: binding_c, type: payload_type, value: arm_expr)
          end
        end
        body = lower_block(
          arm.body,
          env: arm_local_env,
          active_defers: active_defers + local_defers,
          return_type:,
          loop_flow: arm_loop_flow,
          allow_return:,
        )
        body = [binding_decl, *body].compact if binding_decl
        if wildcard_arm_pattern?(arm.pattern)
          IR::SwitchDefaultCase.new(body:)
        else
          arm_name = variant_match_arm_name_from_pattern(arm.pattern)
          IR::SwitchCase.new(value: IR::Name.new(name: enum_member_c_name(scrutinee_type, "kind_#{arm_name}"), type: kind_type, pointer: false), body:)
        end
      end
      lowered << IR::SwitchStmt.new(expression: kind_expr, cases:, exhaustive: true)
    end
  elsif scrutinee_type.is_a?(Types::StringView)
    lower_block_string_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  elsif scrutinee_type.is_a?(Types::Tuple)
    lower_block_tuple_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  else
    has_range_arms = statement.arms.any? { |arm| arm.pattern.is_a?(AST::RangeExpr) }

    if has_range_arms
      lower_block_range_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
    else
      arm_loop_flow = switch_loop_flow(loop_flow, local_defers)
      cases = statement.arms.map do |arm|
        body = lower_block(
          arm.body,
          env: local_env,
          active_defers: active_defers + local_defers,
          return_type:,
          loop_flow: arm_loop_flow,
          allow_return:,
        )
        if wildcard_arm_pattern?(arm.pattern)
          IR::SwitchDefaultCase.new(body:)
        else
          value = lower_expression(arm.pattern, env: local_env, expected_type: scrutinee_type)
          IR::SwitchCase.new(value:, body:)
        end
      end
      lowered << IR::SwitchStmt.new(expression:, cases:, exhaustive: true)
    end
  end
  lowered.concat(expression_cleanups.flat_map(&:itself))
end

#lower_block_range_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
 
# File 'lib/milk_tea/core/lowering/block.rb', line 1114

def lower_block_range_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  arm_loop_flow = switch_loop_flow(loop_flow, local_defers)
  bool_type = @ctx.types.fetch("bool")
  non_wildcard = statement.arms.reject { |arm| wildcard_arm_pattern?(arm.pattern) }
  wildcard = statement.arms.find { |arm| wildcard_arm_pattern?(arm.pattern) }
  else_body = if wildcard
    lower_block(wildcard.body, env: local_env, active_defers: active_defers + local_defers, return_type:, loop_flow: arm_loop_flow, allow_return:)
  else
    []
  end
  non_wildcard.reverse_each do |arm|
    arm_body = lower_block(
      arm.body,
      env: local_env,
      active_defers: active_defers + local_defers,
      return_type:,
      loop_flow: arm_loop_flow,
      allow_return:,
    )
    cond = if arm.pattern.is_a?(AST::RangeExpr)
      lower_range_match_condition(arm.pattern, expression, bool_type, env: local_env)
    else
      lit = lower_expression(arm.pattern, env: local_env, expected_type: scrutinee_type)
      IR::Binary.new(operator: "==", left: expression, right: lit, type: bool_type)
    end
    else_body = [IR::IfStmt.new(condition: cond, then_body: arm_body, else_body:)]
  end
  lowered.concat(else_body)
end

#lower_block_return_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, allow_return:) ⇒ Object

Raises:



455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
 
# File 'lib/milk_tea/core/lowering/block.rb', line 455

def lower_block_return_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, allow_return:)
  raise LoweringError.new("return is not allowed inside defer blocks",
    line: statement.line, column: statement.column, path: @ctx.current_analysis_path) unless allow_return

  value = nil
  prepared_setup = []
  prepared_value = statement.value
  prepared_cleanups = []
  if statement.value
    prepared_setup, prepared_value, prepared_cleanups = prepare_expression_with_cleanups(
      statement.value,
      env: local_env,
      expected_type: return_type,
      allow_root_statement_foreign: true,
      materialize_array_calls: !array_type?(return_type),
    )
    lowered.concat(prepared_setup)
  end
  if prepared_value && (foreign_call = foreign_call_info(prepared_value, local_env))
    setup, value = lower_foreign_call_statement(foreign_call, env: local_env, expected_type: return_type, statement_position: false)
    lowered.concat(setup)
  end
  value ||= prepared_value ? lower_contextual_expression(
    prepared_value,
    env: local_env,
    expected_type: return_type,
    contextual_int_to_float: contextual_int_to_float_target?(return_type),
  ) : nil
  if prepared_cleanups.any? && cstr_trackable_type?(return_type)
    raise LoweringError.new("formatted string temporaries cannot be returned as borrowed text; use std.fmt.format(f\"...\") when ownership must escape",
      line: statement.line, column: statement.column, path: @ctx.current_analysis_path)
  end

  prepared_cleanup_list = prepared_cleanups.flat_map(&:itself)
  if prepared_cleanup_list.any? && return_type.is_a?(Types::Struct) && struct_contains_string_field?(return_type)
    prepared_cleanup_list = prepared_cleanup_list.reject { |stmt| stmt.is_a?(IR::ExpressionStmt) && stmt.expression.is_a?(IR::Call) && stmt.expression.callee == "mt_format_str_release" }
  end
  cleanup = prepared_cleanup_list + cleanup_statements(local_defers, active_defers)
  needs_proc_retain = value && contains_proc_storage_type?(return_type) && !local_defers.empty? && !expression_contains_proc_expr?(prepared_value)
  if value && (!cleanup.empty? && !cleanup_safe_return_expression?(prepared_value) || needs_proc_retain)
    return_value_name = fresh_c_temp_name(local_env, "return_value")
    lowered << IR::LocalDecl.new(name: return_value_name, linkage_name: return_value_name, type: return_type, value:)
    value = IR::Name.new(name: return_value_name, type: return_type, pointer: false)
  end
  lowered.concat(lower_proc_contained_retain_statements(value, return_type)) if needs_proc_retain
  lowered.concat(cleanup)
  lowered << IR::ReturnStmt.new(value:, line: statement.line, path: @ctx.current_analysis_path)
end

#lower_block_string_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
 
# File 'lib/milk_tea/core/lowering/block.rb', line 1049

def lower_block_string_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  arm_loop_flow = switch_loop_flow(loop_flow, local_defers)
  bool_type = @ctx.types.fetch("bool")
  non_wildcard = statement.arms.reject { |arm| wildcard_arm_pattern?(arm.pattern) }
  wildcard = statement.arms.find { |arm| wildcard_arm_pattern?(arm.pattern) }
  else_body = if wildcard
    lower_block(
      wildcard.body,
      env: local_env,
      active_defers: active_defers + local_defers,
      return_type:,
      loop_flow: arm_loop_flow,
      allow_return:,
    )
  else
    []
  end
  non_wildcard.reverse_each do |arm|
    arm_body = lower_block(
      arm.body,
      env: local_env,
      active_defers: active_defers + local_defers,
      return_type:,
      loop_flow: arm_loop_flow,
      allow_return:,
    )
    lit = lower_expression(arm.pattern, env: local_env, expected_type: scrutinee_type)
    cond = IR::Binary.new(operator: "==", left: expression, right: lit, type: bool_type)
    else_body = [IR::IfStmt.new(condition: cond, then_body: arm_body, else_body:)]
  end
  lowered.concat(else_body)
end

#lower_block_tuple_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
 
# File 'lib/milk_tea/core/lowering/block.rb', line 1082

def lower_block_tuple_match_stmt(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  arm_loop_flow = switch_loop_flow(loop_flow, local_defers)
  bool_type = @ctx.types.fetch("bool")
  non_wildcard = statement.arms.reject { |arm| wildcard_arm_pattern?(arm.pattern) }
  wildcard = statement.arms.find { |arm| wildcard_arm_pattern?(arm.pattern) }
  else_body = if wildcard
    lower_block(
      wildcard.body,
      env: local_env,
      active_defers: active_defers + local_defers,
      return_type:,
      loop_flow: arm_loop_flow,
      allow_return:,
    )
  else
    []
  end
  non_wildcard.reverse_each do |arm|
    arm_body = lower_block(
      arm.body,
      env: local_env,
      active_defers: active_defers + local_defers,
      return_type:,
      loop_flow: arm_loop_flow,
      allow_return:,
    )
    cond = tuple_arm_condition(arm, expression, scrutinee_type, bool_type, env: local_env)
    else_body = [IR::IfStmt.new(condition: cond, then_body: arm_body, else_body:)]
  end
  lowered.concat(else_body)
end

#lower_block_unsafe_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



378
379
380
381
382
383
384
385
386
387
388
 
# File 'lib/milk_tea/core/lowering/block.rb', line 378

def lower_block_unsafe_stmt(statement, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  body = lower_block(
    statement.body,
    env: local_env,
    active_defers: active_defers + local_defers,
    return_type:,
    loop_flow: nested_loop_flow(loop_flow, local_defers),
    allow_return:,
  )
  lowered << IR::BlockStmt.new(body:)
end

#lower_block_variant_struct_pattern_match(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
 
# File 'lib/milk_tea/core/lowering/block.rb', line 894

def lower_block_variant_struct_pattern_match(statement, scrutinee_type:, expression:, lowered:, local_defers:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  kind_type = @ctx.types.fetch("int")
  arm_loop_flow = switch_loop_flow(loop_flow, local_defers)
  @match_label_counter ||= 0
  @match_label_counter += 1
  m = @match_label_counter
  match_end_label = "__mt_match_#{m}_end"
  arm_next_label = "__mt_match_#{m}_arm_next"

  statement.arms.each_with_index do |arm, arm_index|
    arm_local_env = duplicate_env(local_env)
    arm_name = variant_match_arm_name_from_pattern(arm.pattern) unless wildcard_arm_pattern?(arm.pattern)

    if arm_index > 0
      lowered << IR::LabelStmt.new(name: "__mt_match_#{m}_arm_#{arm_index}")
    end

    if arm_name && !wildcard_arm_pattern?(arm.pattern)
      tag_value = IR::Name.new(name: enum_member_c_name(scrutinee_type, "kind_#{arm_name}"), type: kind_type, pointer: false)
      tag_expr = IR::Member.new(receiver: expression, member: "kind", type: kind_type)
      goto_label = if arm_index < statement.arms.length - 1
        "__mt_match_#{m}_arm_#{arm_index + 1}"
      else
        arm_next_label
      end
      tag_check = IR::Binary.new(operator: "!=", left: tag_expr, right: tag_value, type: @ctx.types.fetch("bool"))
      lowered << IR::IfStmt.new(condition: tag_check, then_body: [IR::GotoStmt.new(label: goto_label)], else_body: [])
    end

    if arm_name && !wildcard_arm_pattern?(arm.pattern) && scrutinee_type.has_payload?(arm_name)
      fields = scrutinee_type.arm(arm_name)
      payload_type = Types::VariantArmPayload.new(scrutinee_type, arm_name, fields)
      data_expr = IR::Member.new(receiver: expression, member: "data", type: nil)
      arm_expr = IR::Member.new(receiver: data_expr, member: arm_name, type: payload_type)
      payload_c_name = fresh_c_temp_name(arm_local_env, "match_payload")
      arm_local_env[:scopes].last["__mt_payload"] = local_binding(type: payload_type, linkage_name: payload_c_name, mutable: true, pointer: false)

      arm_body_ir = []
      arm_body_ir << IR::LocalDecl.new(name: payload_c_name, linkage_name: payload_c_name, type: payload_type, value: arm_expr)

      nested_struct_fields = nil
      nested_struct_c_name = nil
      nested_struct_type = nil
      if fields.size == 1 && fields.values.first.is_a?(Types::Struct)
        native_field = fields.keys.first
        has_native_reference = arm.pattern.arguments.any? do |arg|
          next false if !arg.name && arg.value.is_a?(AST::Identifier) && arg.value.name == "_"

          name = arg.name || (arg.value.is_a?(AST::Identifier) ? arg.value.name : nil)
          name == native_field
        end
        unless has_native_reference
          nested_struct_type = fields.values.first
          nested_struct_fields = nested_struct_type.fields
          single_field_name = fields.keys.first
          nested_struct_c_name = fresh_c_temp_name(arm_local_env, "match_struct")
          struct_expr = IR::Member.new(
            receiver: IR::Name.new(name: payload_c_name, type: payload_type, pointer: false),
            member: single_field_name,
            type: nested_struct_type,
          )
          arm_body_ir << IR::LocalDecl.new(name: nested_struct_c_name, linkage_name: nested_struct_c_name, type: nested_struct_type, value: struct_expr)
        end
      end

      if arm.pattern.is_a?(AST::Call) && !arm.pattern.arguments.empty?
        pattern_fields = nested_struct_fields || fields
        pattern_receiver_name = nested_struct_c_name || payload_c_name
        pattern_receiver_type = nested_struct_type || payload_type

        arm.pattern.arguments.each do |arg|
          if !arg.name && arg.value.is_a?(AST::BinaryOp) && arg.value.left.is_a?(AST::Identifier)
            field_name = arg.value.left.name
            next unless pattern_fields.key?(field_name)

            field_type = pattern_fields[field_name]
            field_expr = IR::Member.new(receiver: IR::Name.new(name: pattern_receiver_name, type: pattern_receiver_type, pointer: false), member: field_name, type: field_type)
            field_expr = dereference_if_self_ref(field_expr, field_type, scrutinee_type)
            rhs_expr = lower_expression(arg.value.right, env: arm_local_env, expected_type: field_type)
            guard_condition = IR::Binary.new(operator: arg.value.operator, left: field_expr, right: rhs_expr, type: @ctx.types.fetch("bool"))
            arm_body_ir << IR::IfStmt.new(condition: guard_condition, then_body: [], else_body: [IR::GotoStmt.new(label: goto_label)])
          end

          if arg.name
            field_name = arg.name
            next unless pattern_fields.key?(field_name)

            field_type = pattern_fields[field_name]
            field_expr = IR::Member.new(receiver: IR::Name.new(name: pattern_receiver_name, type: pattern_receiver_type, pointer: false), member: field_name, type: field_type)
            field_expr = dereference_if_self_ref(field_expr, field_type, scrutinee_type)
            value_expr = lower_expression(arg.value, env: arm_local_env, expected_type: field_type)
            eq_check = IR::Binary.new(operator: "!=", left: field_expr, right: value_expr, type: @ctx.types.fetch("bool"))
            arm_body_ir << IR::IfStmt.new(condition: eq_check, then_body: [IR::GotoStmt.new(label: goto_label)], else_body: [])
          end
        end

        arm.pattern.arguments.each do |arg|
          next if arg.name
          next unless arg.value.is_a?(AST::Identifier)
          next if arg.value.name == "_"

          field_name = arg.value.name
          next unless pattern_fields.key?(field_name)

          field_type = pattern_fields[field_name]
          binding_c = c_local_name(field_name)
          field_expr = IR::Member.new(receiver: IR::Name.new(name: pattern_receiver_name, type: pattern_receiver_type, pointer: false), member: field_name, type: field_type)
          field_expr = dereference_if_self_ref(field_expr, field_type, scrutinee_type)
          arm_body_ir << IR::LocalDecl.new(name: binding_c, linkage_name: binding_c, type: field_type, value: field_expr)
          arm_local_env[:scopes].last[field_name] = local_binding(type: field_type, linkage_name: binding_c, mutable: false, pointer: false)
        end
      end

      if arm.binding_name && !wildcard_arm_pattern?(arm.pattern)
        binding_c = c_local_name(arm.binding_name)
        if arm_name && scrutinee_type.has_payload?(arm_name)
          payload_key = "__mt_payload"
          if arm_local_env[:scopes].last.key?(payload_key)
            payload_binding = arm_local_env[:scopes].last[payload_key]
            arm_local_env[:scopes].last[arm.binding_name] = local_binding(type: payload_binding[:type], linkage_name: binding_c, mutable: true, pointer: false)
            payload_ref = IR::Name.new(name: payload_binding[:linkage_name], type: payload_binding[:type], pointer: false)
            arm_body_ir << IR::LocalDecl.new(name: arm.binding_name, linkage_name: binding_c, type: payload_binding[:type], value: payload_ref)
          end
        end
      end

      body = lower_block(
        arm.body,
        env: arm_local_env,
        active_defers: active_defers + local_defers,
        return_type:,
        loop_flow: arm_loop_flow,
        allow_return:,
      )
      arm_body_ir.concat(body)
      arm_body_ir << IR::GotoStmt.new(label: match_end_label)

      lowered << IR::BlockStmt.new(body: arm_body_ir)
    else
      body = lower_block(
        arm.body,
        env: arm_local_env,
        active_defers: active_defers + local_defers,
        return_type:,
        loop_flow: arm_loop_flow,
        allow_return:,
      )
      lowered << IR::BlockStmt.new(body: body + [IR::GotoStmt.new(label: match_end_label)])
    end
  end

  lowered << IR::LabelStmt.new(name: arm_next_label)
  lowered << IR::LabelStmt.new(name: match_end_label)
end

#lower_block_when_stmt(statement, lowered:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
 
# File 'lib/milk_tea/core/lowering/block.rb', line 390

def lower_block_when_stmt(statement, lowered:, local_env:, active_defers:, return_type:, loop_flow:, allow_return:)
  discriminant = compile_time_const_value(statement.discriminant)
  chosen_branch = statement.branches.find do |branch|
    discriminant == compile_time_const_value(branch.pattern)
  end

  if chosen_branch
    lowered.concat(lower_block(
      chosen_branch.body,
      env: local_env,
      active_defers:,
      return_type:,
      loop_flow:,
      allow_return:,
    ))
  elsif statement.else_body
    lowered.concat(lower_block(
      statement.else_body,
      env: local_env,
      active_defers:,
      return_type:,
      loop_flow:,
      allow_return:,
    ))
  end
end

#lower_destructure_decl(statement, env:, lowered:, local_defers:, active_defers:, return_type:, loop_flow:, allow_return:) ⇒ Object 



320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
 
# File 'lib/milk_tea/core/lowering/block.rb', line 320

def lower_destructure_decl(statement, env:, lowered:, local_defers:, active_defers:, return_type:, loop_flow:, allow_return:)
  value_type = infer_expression_type(statement.value, env:)
  setup, prepared_value, _cleanups = prepare_expression_with_cleanups(statement.value, env:, expected_type: value_type)
  lowered.concat(setup)
  value = lower_contextual_expression(prepared_value, env:, expected_type: value_type)

  temp_name = fresh_c_temp_name(env, "destructure_val")
  lowered << IR::LocalDecl.new(name: temp_name, linkage_name: temp_name, type: value_type, value:)

  if statement.destructure_type_name
    # Struct destructure: find fields by name in the struct type
    destructure_type = value_type
    fields = destructure_type.fields
    statement.destructure_bindings.each do |name|
      next if name == "_"
      field_type = fields[name]
      field_expr = IR::Member.new(receiver: IR::Name.new(name: temp_name, type: destructure_type, pointer: false), member: name, type: field_type)
      decl_c_name = c_local_name(name)
      lowered << IR::LocalDecl.new(name: decl_c_name, linkage_name: decl_c_name, type: field_type, value: field_expr)
      env[:scopes].last[name] = local_binding(type: field_type, linkage_name: decl_c_name, mutable: false, pointer: false)
    end
  else
    # Tuple destructure: index by position
    statement.destructure_bindings.each_with_index do |name, index|
      next if name == "_"
      field_name = value_type.field_names[index]
      field_type = value_type.element_types[index]
      field_expr = IR::Member.new(receiver: IR::Name.new(name: temp_name, type: value_type, pointer: false), member: field_name, type: field_type)
      decl_c_name = c_local_name(name)
      lowered << IR::LocalDecl.new(name: decl_c_name, linkage_name: decl_c_name, type: field_type, value: field_expr)
      env[:scopes].last[name] = local_binding(type: field_type, linkage_name: decl_c_name, mutable: false, pointer: false)
    end
  end
end

#lower_emit_stmt(statement, env:) ⇒ Object 



274
275
276
277
278
279
280
281
282
283
284
285
286
287
 
# File 'lib/milk_tea/core/lowering/block.rb', line 274

def lower_emit_stmt(statement, env:)
  decl = statement.declaration
  case decl
  when AST::FunctionDef
    lower_emitted_function(decl, env:)
  when AST::StructDecl
    lower_emitted_struct(decl)
  when AST::ConstDecl
    lower_emitted_const(decl, env:)
  else
    raise LoweringError.new("emit is not supported for #{decl.class.name}",
      line: statement.line, column: statement.column, path: @ctx.current_analysis_path)
  end
end

#lower_emitted_const(decl, env:) ⇒ Object 



355
356
357
358
359
360
361
362
 
# File 'lib/milk_tea/core/lowering/block.rb', line 355

def lower_emitted_const(decl, env:)
  value = lower_static_storage_initializer(decl.value, env:, expected_type: decl.type ? resolve_type_ref(decl.type) : nil)
  type = decl.type ? resolve_type_ref(decl.type) : infer_expression_type(decl.value, env:)
  linkage_name = value_c_name(decl.name)
  constant = IR::Constant.new(name: decl.name, linkage_name:, type:, value:, line: decl.line, path: @ctx.current_analysis_path)
  @artifacts.emitted_declarations << constant
  []
end

#lower_emitted_function(decl, env:) ⇒ Object 



289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
 
# File 'lib/milk_tea/core/lowering/block.rb', line 289

def lower_emitted_function(decl, env:)
  params = []
  param_setup = []
  return_type = decl.return_type ? resolve_type_ref(decl.return_type) : @ctx.types.fetch("void")
  linkage_name = "#{@ctx.module_prefix}#{decl.name}"

  decl.params.each do |param|
    param_type = param.type ? resolve_type_ref(param.type) : @ctx.types.fetch("int")
    param_linkage_name = c_local_name(param.name)
    params << IR::Param.new(name: param.name, linkage_name: param_linkage_name, type: param_type, pointer: false)
    env[:scopes].last[param.name] = local_binding(type: param_type, linkage_name: param_linkage_name, mutable: false, pointer: false)
  end

  body = lower_block(decl.body, env:, active_defers: [], return_type:, loop_flow: nil, allow_return: true)
  body = param_setup + body
  func = IR::Function.new(name: decl.name, linkage_name:, params:, return_type:, body:, entry_point: false, method_receiver_param: false)
  @artifacts.emitted_declarations << func
  []
end

#lower_emitted_struct(decl) ⇒ Object 



309
310
311
312
313
314
315
316
317
318
 
# File 'lib/milk_tea/core/lowering/block.rb', line 309

def lower_emitted_struct(decl)
  fields = decl.fields.map do |field|
    field_type = field.type ? resolve_type_ref(field.type) : @ctx.types.fetch("int")
    IR::Field.new(name: field.name, type: field_type)
  end
  linkage_name = "#{@ctx.module_prefix}#{decl.name}"
  struct_decl = IR::StructDecl.new(name: decl.name, linkage_name:, fields:, packed: decl.respond_to?(:packed) ? decl.packed : false, alignment: nil)
  @artifacts.emitted_declarations << struct_decl
  []
end

#lower_inline_for_stmt(statement, env:, active_defers:, return_type:, allow_return:) ⇒ Object 



167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
 
# File 'lib/milk_tea/core/lowering/block.rb', line 167

def lower_inline_for_stmt(statement, env:, active_defers:, return_type:, allow_return:)
  iterable = compile_time_const_value(statement.iterables.first, env:)
  return [] unless iterable.is_a?(Array) && !iterable.empty?

  loop_var_name = statement.bindings.first.name
  loop_var_type = inline_loop_element_type(iterable.first)
  lowered = []

  iterable.each do |element|
    iter_env = duplicate_env(env)
    current_actual_scope(iter_env[:scopes])[loop_var_name] = local_binding(
      type: loop_var_type,
      linkage_name: c_local_name(loop_var_name),
      mutable: false,
      pointer: false,
      const_value: element,
    )
    emit_stmts, other_stmts = statement.body.partition { |s| s.is_a?(AST::EmitStmt) }
    emit_stmts.each do |emit_stmt|
      lowered.concat(lower_emit_stmt(emit_stmt, env: iter_env))
    rescue LoweringError
      # emit for compile-time-only constructs — skip
    end

    unless other_stmts.empty?
      saved_type_env = @type_resolution_env
      saved_bypass = @bypass_sema_type_cache
      # Each unrolled iteration may bind the loop var to a different value
      # (e.g. a field whose `.type` differs per field), so expression types
      # must be re-inferred per iteration instead of reusing the single
      # sema-cached type computed for the representative first element.
      @type_resolution_env = iter_env
      @bypass_sema_type_cache = true
      begin
        body = lower_block(other_stmts, env: iter_env, active_defers:, return_type:, loop_flow: nil, allow_return:)
      ensure
        @type_resolution_env = saved_type_env
        @bypass_sema_type_cache = saved_bypass
      end
      lowered << IR::BlockStmt.new(body:) unless body.empty?
    end
  end

  lowered
end

#lower_inline_if_stmt(statement, env:, active_defers:, return_type:, allow_return:) ⇒ Object 



230
231
232
233
234
235
236
237
238
239
240
241
242
243
 
# File 'lib/milk_tea/core/lowering/block.rb', line 230

def lower_inline_if_stmt(statement, env:, active_defers:, return_type:, allow_return:)
  chosen_branch = statement.branches.find do |branch|
    ct_value = compile_time_const_value(branch.condition, env:)
    ct_value == true
  end

  if chosen_branch
    lower_block(chosen_branch.body, env:, active_defers:, return_type:, loop_flow: nil, allow_return:)
  elsif statement.else_body
    lower_block(statement.else_body, env:, active_defers:, return_type:, loop_flow: nil, allow_return:)
  else
    []
  end
end

#lower_inline_match_stmt(statement, env:, active_defers:, return_type:, allow_return:) ⇒ Object 



245
246
247
248
249
250
251
252
253
254
255
256
 
# File 'lib/milk_tea/core/lowering/block.rb', line 245

def lower_inline_match_stmt(statement, env:, active_defers:, return_type:, allow_return:)
  scrutinee = compile_time_const_value(statement.expression, env:)
  return [] unless scrutinee

  chosen_arm = statement.arms.find do |arm|
    scrutinee == compile_time_const_value(arm.pattern, env:)
  end

  return [] unless chosen_arm

  lower_block(chosen_arm.body, env:, active_defers:, return_type:, loop_flow: nil, allow_return:)
end

#lower_inline_while_stmt(statement, env:, active_defers:, return_type:, allow_return:) ⇒ Object 



213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
 
# File 'lib/milk_tea/core/lowering/block.rb', line 213

def lower_inline_while_stmt(statement, env:, active_defers:, return_type:, allow_return:)
  condition = compile_time_const_value(statement.condition, env:)
  return [] unless condition

  iterations = 0
  max_iterations = 10_000
  lowered = []

  while compile_time_const_value(statement.condition, env:) && iterations < max_iterations
    body = lower_block(statement.body, env:, active_defers:, return_type:, loop_flow: nil, allow_return:)
    lowered << IR::BlockStmt.new(body:) unless body.empty?
    iterations += 1
  end

  lowered
end

#lower_proc_expression_for_local(expression, env:, local_name:, proc_type:) ⇒ Object 



84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
 
# File 'lib/milk_tea/core/lowering/block.rb', line 84

def lower_proc_expression_for_local(expression, env:, local_name:, proc_type:)
  captures = proc_capture_entries(expression, env)
  captures.each do |capture|
    if ref_type?(capture[:type]) || contains_ref_type?(capture[:type])
      raise LoweringError.new("proc capture #{capture[:name]} cannot use ref types",
        line: expression.line, column: expression.column, path: @ctx.current_analysis_path)
    end
  end

  proc_id = fresh_proc_symbol
  invoke_c_name = "#{@ctx.module_prefix}__proc_#{proc_id}__invoke"
  release_linkage_name = "#{@ctx.module_prefix}__proc_#{proc_id}__release"
  retain_c_name = "#{@ctx.module_prefix}__proc_#{proc_id}__retain"
  env_struct_type = nil
  setup = []

  env_value = if captures.empty?
    IR::NullLiteral.new(type: proc_env_pointer_type)
  else
    env_struct_type = Types::Struct.new("#{@ctx.module_prefix}__proc_#{proc_id}__env").define_fields(
      { "__mt_ref_count" => @ctx.types.fetch("ptr_uint") }.merge(captures.each_with_object({}) { |capture, fields| fields[capture[:field_name]] = capture[:type] }),
    )
    @artifacts.synthetic_structs << IR::StructDecl.new(
      name: env_struct_type.name,
      linkage_name: env_struct_type.name,
      fields: [IR::Field.new(name: "__mt_ref_count", type: @ctx.types.fetch("ptr_uint")), *captures.map { |capture| IR::Field.new(name: capture[:field_name], type: capture[:type]) }],
      packed: false,
      alignment: nil,
    )

    env_pointer_type = pointer_to(env_struct_type)
    env_name = fresh_c_temp_name(env, "#{local_name}_env")
    raw_allocation = IR::Call.new(
      callee: "mt_async_alloc",
      arguments: [IR::SizeofExpr.new(target_type: env_struct_type, type: @ctx.types.fetch("ptr_uint"))],
      type: proc_env_pointer_type,
    )
    setup << IR::LocalDecl.new(
      name: env_name,
      linkage_name: env_name,
      type: env_pointer_type,
      value: IR::Cast.new(target_type: env_pointer_type, expression: raw_allocation, type: env_pointer_type),
    )
    env_pointer = IR::Name.new(name: env_name, type: env_pointer_type, pointer: false)
    setup << IR::Assignment.new(
      target: IR::Member.new(receiver: env_pointer, member: "__mt_ref_count", type: @ctx.types.fetch("ptr_uint")),
      operator: "=",
      value: IR::IntegerLiteral.new(value: 1, type: @ctx.types.fetch("ptr_uint")),
    )
    captures.each do |capture|
      setup << IR::Assignment.new(
        target: IR::Member.new(receiver: env_pointer, member: capture[:field_name], type: capture[:type]),
        operator: "=",
        value: lower_expression(AST::Identifier.new(name: capture[:name]), env:, expected_type: capture[:type]),
      )
    end
    captures.each do |capture|
      next unless contains_proc_storage_type?(capture[:type])

      member = IR::Member.new(receiver: env_pointer, member: capture[:field_name], type: capture[:type])
      setup.concat(lower_proc_contained_retain_statements(member, capture[:type]))
    end
    IR::Cast.new(target_type: proc_env_pointer_type, expression: env_pointer, type: proc_env_pointer_type)
  end

  @artifacts.synthetic_functions << build_proc_invoke_function(expression, proc_type, captures, env_struct_type, invoke_c_name)
  @artifacts.synthetic_functions << build_proc_release_function(release_linkage_name, env_struct_type)
  @artifacts.synthetic_functions << build_proc_retain_function(retain_c_name, env_struct_type)

  [
    setup,
    IR::AggregateLiteral.new(
      type: proc_type,
      fields: [
        IR::AggregateField.new(name: "env", value: env_value),
        IR::AggregateField.new(name: "invoke", value: IR::Name.new(name: invoke_c_name, type: proc_invoke_function_type(proc_type), pointer: false)),
        IR::AggregateField.new(name: "release", value: IR::Name.new(name: release_linkage_name, type: proc_release_function_type, pointer: false)),
        IR::AggregateField.new(name: "retain", value: IR::Name.new(name: retain_c_name, type: proc_retain_function_type, pointer: false)),
      ],
    ),
  ]
end

#variant_self_referencing_field?(field_type, scrutinee_type) ⇒ Boolean

Returns:

  • (Boolean) 


364
365
366
367
368
 
# File 'lib/milk_tea/core/lowering/block.rb', line 364

def variant_self_referencing_field?(field_type, scrutinee_type)
  return false unless field_type.is_a?(Types::Variant) || field_type.is_a?(Types::VariantInstance)
  return false unless scrutinee_type.is_a?(Types::Variant) || scrutinee_type.is_a?(Types::VariantInstance)
  field_type == scrutinee_type
end