Module: Rigor::Inference::MethodDispatcher

Defined in:
lib/rigor/inference/method_dispatcher.rb,
lib/rigor/inference/method_dispatcher/file_folding.rb,
lib/rigor/inference/method_dispatcher/rbs_dispatch.rb,
lib/rigor/inference/method_dispatcher/block_folding.rb,
lib/rigor/inference/method_dispatcher/method_folding.rb,
lib/rigor/inference/method_dispatcher/shape_dispatch.rb,
lib/rigor/inference/method_dispatcher/kernel_dispatch.rb,
lib/rigor/inference/method_dispatcher/constant_folding.rb,
lib/rigor/inference/method_dispatcher/iterator_dispatch.rb,
lib/rigor/inference/method_dispatcher/overload_selector.rb,
lib/rigor/inference/method_dispatcher/receiver_affinity.rb,
lib/rigor/inference/method_dispatcher/literal_string_folding.rb

Overview

Coordinates method dispatch for the inference engine.

Given ‘(receiver_type, method_name, arg_types, block_type, environment)`, the dispatcher returns the inferred result type or `nil` when no rule matches. `nil` is a deliberately blunt “I don’t know” signal: callers (today only ‘ExpressionTyper`) own the fail-soft fallback and decide whether to record a `FallbackTracer` event.

Tiers (in order):

  1. ConstantFolding: executes the Ruby operation directly when the receiver and argument are ‘Constant` carriers and the method is on the curated whitelist. Slice 2.

  2. ShapeDispatch: returns the precise element/value type for a curated catalogue of ‘Tuple`/`HashShape` element-access methods (`first`, `last`, `[]` with a static integer/key, `fetch`, `dig`, `size`/`length`/`count`). Slice 5 phase 2.

  3. RbsDispatch: looks up the receiver’s class in the RBS environment carried by the scope and translates the method’s return type into a Rigor::Type. Slice 4.

‘ShapeDispatch` deliberately runs above RbsDispatch so the precise per-position/per-key answer wins over the projected `Array#[]`/`Hash#fetch` answer; it falls through (`nil`) when the call cannot be proved against the static shape, in which case the projection answer from RbsDispatch applies.

The dispatcher’s public signature reserves space for ‘block_type:` and ADR-2 plugin extensions (later slices), so call sites added now do not have to be rewritten when those tiers arrive.

Defined Under Namespace

Modules: BlockFolding, ConstantFolding, FileFolding, IteratorDispatch, KernelDispatch, LiteralStringFolding, MethodFolding, OverloadSelector, RbsDispatch, ReceiverAffinity, ShapeDispatch

Class Method Summary collapse

Class Method Details

.array_new_fill(type) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 837

def array_new_fill(type)
  return Type::Combinator.constant_of(nil) if type.nil?

  type
end

.array_new_lift(class_name, arg_types) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 820

def array_new_lift(class_name, arg_types)
  return nil unless class_name == "Array"
  return nil if arg_types.empty? || arg_types.size > 2

  size = array_new_size(arg_types.first)
  return nil if size.nil? || size.negative? || size > ARRAY_NEW_TUPLE_LIMIT

  fill = array_new_fill(arg_types[1])
  Type::Combinator.tuple_of(*Array.new(size, fill))
end

.array_new_size(type) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 831

def array_new_size(type)
  return nil unless type.is_a?(Type::Constant) && type.value.is_a?(Integer)

  type.value
end

.boundary_cross_class_name(receiver_type, environment, rbs_result) ⇒ Object

Composite preflight for #record_boundary_cross_if_applicable. Returns the receiver class name only when every prerequisite for emitting the diagnostic is satisfied (environment carries an index + reporter, receiver is a nominal carrier, RBS-side result is not the trivial ‘Dynamic` envelope). Returns `nil` to short-circuit otherwise.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 563

def boundary_cross_class_name(receiver_type, environment, rbs_result)
  return nil if environment.nil?
  return nil if environment.dependency_source_index.nil?
  return nil if environment.dependency_source_index.empty?
  return nil if environment.boundary_cross_reporter.nil?
  return nil if rbs_result_untyped?(rbs_result)

  dep_source_class_name(receiver_type)
end

.budget_silence_result(class_name, index, _environment) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 583

def budget_silence_result(class_name, index, _environment)
  return nil unless index.budget_overrun_strategy == :dependency_silence

  owning_gem = index.gem_for(class_name)
  return nil if owning_gem.nil?
  return nil unless index.budget_exceeded.include?(owning_gem)

  Type::Combinator.untyped
end

.collect_plugin_contributions(registry, call_node, scope) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 618

def collect_plugin_contributions(registry, call_node, scope)
  registry.plugins.filter_map do |plugin|
    contribution = plugin.flow_contribution_for(call_node: call_node, scope: scope)
    contribution.is_a?(FlowContribution) ? contribution : nil
  rescue StandardError
    nil
  end
end

.constant_constructor_lift(class_name, arg_types) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 798

def constant_constructor_lift(class_name, arg_types)
  builder = CONSTANT_CONSTRUCTORS[class_name]
  return nil if builder.nil?
  return nil unless arg_types.size == 1

  arg = arg_types.first
  return nil unless arg.is_a?(Type::Constant) && arg.value.is_a?(String)

  result = builder.call(arg.value)
  Type::Combinator.constant_of(result)
rescue StandardError
  nil
end

.constant_metaclass(value) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 851

def constant_metaclass(value)
  CONSTANT_METACLASSES.each do |klass, name|
    return Type::Combinator.singleton_of(name) if value.is_a?(klass)
  end
  nil
end

.dep_source_class_name(receiver_type) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 612

def dep_source_class_name(receiver_type)
  case receiver_type
  when Type::Nominal, Type::Singleton then receiver_type.class_name
  end
end

.dependency_source_return_type(contribution) ⇒ Object

Maps a DependencySourceInference::Walker::CatalogEntry to the Type the dispatcher returns at the call site. When the heuristic recovered a static facet, wrap it in ‘Dynamic` per ADR-10’s gem-boundary contract; otherwise fall back to the pre-heuristic ‘Dynamic`.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 551

def dependency_source_return_type(contribution)
  return Type::Combinator.untyped if contribution.return_type.nil?

  Type::Combinator.dynamic(contribution.return_type)
end

.discovered_method_lookup(receiver_type) ⇒ Object

Resolves the ‘(class_name, kind)` pair scope_indexer keys its `discovered_methods` table on. `Nominal` looks up instance methods on X; `Singleton` looks up singleton methods on X. Other carriers return `[nil, nil]` so the tier declines.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 241

def discovered_method_lookup(receiver_type)
  case receiver_type
  when Type::Nominal then [receiver_type.class_name, :instance]
  when Type::Singleton then [receiver_type.class_name, :singleton]
  else [nil, nil]
  end
end

.dispatch(receiver_type:, method_name:, arg_types:, block_type: nil, environment: nil, call_node: nil, scope: nil) ⇒ Rigor::Type?

Returns inferred result type, or ‘nil` for “no rule”.

Parameters:

  • receiver_type (Rigor::Type, nil) —

    type of the receiver expression, or ‘nil` for an implicit-self call.

  • method_name (Symbol)
  • arg_types (Array<Rigor::Type>) —

    positional argument types.

  • block_type (Rigor::Type, nil) (defaults to: nil) —

    inferred return type of the accompanying ‘do … end` / `{ … }` block (Slice 6 phase C sub-phase 2). When non-nil, the dispatcher prefers an overload that declares a block, and binds the method’s block-return type variable to ‘block_type` so a return type like `Array` resolves to `Array`.

  • environment (Rigor::Environment, nil) (defaults to: nil) —

    required for RBS-backed dispatch; when nil only constant folding can fire.

Returns:

  • (Rigor::Type, nil) —

    inferred result type, or ‘nil` for “no rule”.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 67

def dispatch(receiver_type:, method_name:, arg_types:, # rubocop:disable Metrics/MethodLength
             block_type: nil, environment: nil,
             call_node: nil, scope: nil)
  return nil if receiver_type.nil?

  bound_method_result = MethodFolding.try_backward(
    receiver: receiver_type, method_name: method_name, args: arg_types,
    block_type: block_type, environment: environment,
    call_node: call_node, scope: scope
  )
  return bound_method_result if bound_method_result

  precise = dispatch_precise_tiers(receiver_type, method_name, arg_types, block_type)
  return precise if precise

  # v0.1.1 Track 2 slice 7 — plugin return-type contribution
  # tier. Sits ahead of `RbsDispatch` so a plugin that
  # understands a domain-specific dispatch (e.g. an
  # `ActiveRecord::Base.find` returning `Nominal[<resolved
  # model>]`) wins over the RBS-projected envelope. Only
  # consults the registry when both `call_node` and `scope`
  # are supplied — the dispatcher's own internal callers
  # (per-element block fold, etc.) skip this tier.
  plugin_result = try_plugin_contribution(call_node, scope)
  return plugin_result if plugin_result

  # ADR-20 slice 3 — Rigor-bundled HKT-builtin return-
  # type tier. Sits ABOVE `RbsDispatch.try_dispatch` so
  # the handful of stdlib methods whose upstream RBS
  # signature is `untyped` but whose runtime shape Rigor
  # models via a Lightweight HKT (`json::value`,
  # eventually `dry_monads::result`, …) get the reduced
  # type instead of `Dynamic[Top]`. The table that
  # populates this tier lives in
  # `Rigor::Builtins::HktBuiltins::METHOD_RETURN_OVERRIDES`;
  # plugin-supplied per-method overrides are out of
  # scope for slice 3 and continue to flow through the
  # `try_plugin_contribution` tier above.
  hkt_builtin_result = try_hkt_builtin_return(receiver_type, method_name, arg_types, environment)
  return hkt_builtin_result if hkt_builtin_result

  # Rigor-bundled static refinement tier. Sits between HKT
  # and RBS so stdlib methods whose upstream RBS is broader
  # than the documented behaviour (e.g. `Kernel#__dir__`
  # declared `() -> String?` when the documented return is
  # `non-empty-string | nil`) get the tightened type
  # without modifying the vendored `ruby/rbs` submodule.
  # The override table lives in
  # `Rigor::Builtins::StaticReturnRefinements::OVERRIDES`.
  static_refinement = try_static_refinement(receiver_type, method_name, arg_types)
  return static_refinement if static_refinement

  rbs_result = RbsDispatch.try_dispatch(
    receiver: receiver_type, method_name: method_name, args: arg_types,
    environment: environment, block_type: block_type
  )
  if rbs_result
    record_boundary_cross_if_applicable(receiver_type, method_name, rbs_result, environment)
    return rbs_result
  end

  # ADR-16 Tier B / Tier C — synthetic-method tier. Sits
  # BELOW RBS dispatch (per WD13: user-authored RBS overrides
  # substrate synthesis) and ABOVE the dependency-source
  # inference tier so a plugin's declared emit table beats
  # the generic gem-source fallback for the same class. Slice
  # 6a-TierB (origin_module dispatch) lands precise return
  # types for Tier B emissions; Tier C emissions still return
  # `Dynamic[T]` at this tier (slice 6b is the Tier C
  # promotion via ADR-13's resolver chain).
  synthetic_result = try_synthetic_method(
    receiver_type, method_name, arg_types, block_type, environment
  )
  return synthetic_result if synthetic_result

  # ADR-17 slice 2 — project-side patched-method tier.
  # Sits BELOW the substrate / plugin tiers and ABOVE
  # dependency-source inference per ADR-17 § "Inference
  # contract". When the user's `pre_eval:` list named a
  # file that re-opens a class (e.g.,
  # `lib/core_ext/string_extensions.rb` declaring
  # `class String; def to_url; end; end`), the pre-pass
  # populated `ProjectPatchedMethods` with the `(class,
  # method, kind)` triple; this tier surfaces it as
  # `Dynamic[top]` so the patched call resolves
  # cross-file without `call.undefined-method`.
  patched_result = try_project_patched_method(receiver_type, method_name, environment)
  return patched_result if patched_result

  # ADR-10 slice 2b-ii — dependency-source inference tier.
  # Sits BELOW RBS dispatch (RBS / RBS::Inline / generated
  # stubs / plugin contracts always win) and ABOVE the
  # user-class fallback so a method defined in an opt-in
  # gem stops emitting `call.undefined-method` even when
  # no signature contract resolves. Returns
  # `Dynamic[top]` — slice 2b-ii deliberately stops at the
  # dynamic-origin envelope; per-method return-type
  # precision is queued for a later slice.
  dep_source_result = try_dependency_source(receiver_type, method_name, environment)
  return dep_source_result if dep_source_result

  # v0.1.3 — discovered-method dispatch tier. When the
  # receiver class has no RBS BUT scope_indexer recorded
  # `def method_name` for that class (or singleton), the
  # call dispatches to `Dynamic[top]` rather than falling
  # through to the user-class fallback. Sits below RBS /
  # dependency-source so authoritative signatures still win.
  # The scope-indexer-built table records every project-side
  # `def`, `define_method`, and `alias_method`; the
  # `discovered_method?` consult here closes the
  # fail-soft-event hot spot on implicit-self calls
  # (`sibling_private(...)`) inside `lib/rigor/`'s own
  # internals (analyser private helpers don't have RBS).
  discovered_result = try_discovered_method(receiver_type, method_name, scope)
  return discovered_result if discovered_result

  # Slice 7 phase 10 — user-class ancestor fallback. When
  # the receiver is `Nominal[T]` or `Singleton[T]` for a
  # class not in the RBS environment (typically a
  # user-defined class), retry the dispatch against the
  # implicit ancestor: `Nominal[Object]` for instance
  # receivers and `Singleton[Object]` for singleton
  # receivers. This resolves Kernel intrinsics
  # (`require`, `raise`, `puts`, ...) and Module/Class
  # introspection (`attr_reader`, `private`, ...) on
  # user classes without requiring the user to author
  # their own RBS.
  try_user_class_fallback(receiver_type, method_name, arg_types, environment, block_type, call_node)
end

.dispatch_precise_tiers(receiver_type, method_name, arg_types, block_type = nil) ⇒ Object

Runs the precision tiers (constant fold, shape dispatch, file-path fold, block fold) in order and returns the first non-nil answer. Each tier owns its own receiver/argument shape checks; a tier that does not recognise the receiver returns nil so the next tier can try. The RBS tier sits below this chain and is invoked by the outer ‘dispatch` method.

‘BlockFolding` runs last among the precision tiers because its rules apply only to block-taking calls, so the cheaper arity-based fold tiers above it filter out the common cases first. When `block_type` is nil the tier is a no-op.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 639

def dispatch_precise_tiers(receiver_type, method_name, arg_types, block_type = nil)
  meta_result = try_meta_introspection(receiver_type, method_name, arg_types)
  return meta_result if meta_result

  ConstantFolding.try_fold(receiver: receiver_type, method_name: method_name, args: arg_types) ||
    LiteralStringFolding.try_dispatch(receiver: receiver_type, method_name: method_name, args: arg_types) ||
    ShapeDispatch.try_dispatch(receiver: receiver_type, method_name: method_name, args: arg_types) ||
    FileFolding.try_dispatch(receiver: receiver_type, method_name: method_name, args: arg_types) ||
    KernelDispatch.try_dispatch(receiver: receiver_type, method_name: method_name, args: arg_types) ||
    MethodFolding.try_forward(receiver: receiver_type, method_name: method_name, args: arg_types) ||
    BlockFolding.try_fold(
      receiver: receiver_type, method_name: method_name, args: arg_types, block_type: block_type
    )
end

.expected_block_param_types(receiver_type:, method_name:, arg_types:, environment: nil) ⇒ Array<Rigor::Type>

Returns the positional block parameter types declared by the receiving method’s selected RBS overload, translated into ‘Rigor::Type`. Used by the StatementEvaluator’s CallNode handler to bind block parameter names before evaluating the block body.

The probe is best-effort: it returns an empty array whenever the receiver, environment, method definition, or selected overload does not provide statically declared block parameter types. Callers MUST treat the empty array as “no information”; the binder falls back to ‘Dynamic` for every parameter slot in that case.

Parameters:

Returns:



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# File 'lib/rigor/inference/method_dispatcher.rb', line 876

def expected_block_param_types(receiver_type:, method_name:, arg_types:, environment: nil)
  return [] if receiver_type.nil?

  iterator_result = IteratorDispatch.block_param_types(
    receiver: receiver_type,
    method_name: method_name,
    args: arg_types
  )
  return iterator_result if iterator_result

  RbsDispatch.block_param_types(
    receiver: receiver_type,
    method_name: method_name,
    args: arg_types,
    environment: environment
  )
end

.explicit_non_self_receiver?(call_node) ⇒ Boolean

True when the call node carries an explicit receiver that is not the literal ‘self`. Such a call cannot legally dispatch to a private method, so the user-class fallback must skip private signatures rather than return a confidently-wrong type. Returns false for implicit-self calls and `self.`-receiver calls (both may legally reach a private method in modern Ruby), and false when no `call_node` is supplied (internal dispatcher callers).

Returns:

  • (Boolean) 


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# File 'lib/rigor/inference/method_dispatcher.rb', line 696

def explicit_non_self_receiver?(call_node)
  return false if call_node.nil?
  return false unless call_node.respond_to?(:receiver)

  receiver = call_node.receiver
  return false if receiver.nil?

  !receiver.is_a?(Prism::SelfNode)
end

.meta_class(receiver_type) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 746

def meta_class(receiver_type)
  case receiver_type
  when Type::Nominal then Type::Combinator.singleton_of(receiver_type.class_name)
  when Type::Constant then constant_metaclass(receiver_type.value)
  end
end

.meta_new(receiver_type, arg_types = []) ⇒ Object

‘Singleton.new` returns `Nominal` (a fresh instance), regardless of whether Foo is in RBS. This short-circuits the Class.new generic-`instance` plumbing for user classes, so a discovered-class `ScanAccumulator.new` types as `Nominal` rather than `Class`.

v0.0.7 — for the curated set of immutable scalar-shaped classes that ‘Type::Constant::SCALAR_CLASSES` accepts (today: `Pathname`), `.new(Constant<…>)` lifts to a `Constant<…>` carrier so downstream method calls fold through the standard catalog tier.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 765

def meta_new(receiver_type, arg_types = [])
  return nil unless receiver_type.is_a?(Type::Singleton)

  constant_lift = constant_constructor_lift(receiver_type.class_name, arg_types)
  return constant_lift if constant_lift

  array_lift = array_new_lift(receiver_type.class_name, arg_types)
  return array_lift if array_lift

  Type::Combinator.nominal_of(receiver_type.class_name)
end

.plugin_owns_receiver?(class_name, environment) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rigor/inference/method_dispatcher.rb', line 593

def plugin_owns_receiver?(class_name, environment)
  registry = environment&.plugin_registry
  return false if registry.nil? || registry.empty?

  registry.plugins.any? do |plugin|
    owns = plugin.manifest.owns_receivers # rigor:disable undefined-method
    owns.any? { |owner| receiver_matches_owner?(class_name, owner, environment) }
  end
end

.promote_synthetic_match(matches, method_name, arg_types, block_type, environment) ⇒ Object

First non-nil promotion wins. Tier B (origin_module) and Tier C (return_type nominal lookup) are tried in the same registration-order pass per WD11 first-wins —the slice-3b scanner sets ‘origin_module` for Tier B entries and leaves it absent for Tier C, so the two paths self-route per match.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 402

def promote_synthetic_match(matches, method_name, arg_types, block_type, environment)
  return nil if environment.nil?

  matches.each do |synthetic|
    promoted =
      promote_via_origin_module(synthetic, method_name, arg_types, block_type, environment) ||
      promote_via_return_type(synthetic, environment)
    return promoted if promoted
  end
  nil
end

.promote_via_origin_module(synthetic, method_name, arg_types, block_type, environment) ⇒ Object

Slice 6a-TierB. For Tier B emissions (origin_module recorded in provenance), redispatch the call on the included module’s ‘Nominal` type via `RbsDispatch`. Returns nil when the SyntheticMethod is not a Tier B entry or when the origin_module is not in the RBS env.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 419

def promote_via_origin_module(synthetic, method_name, arg_types, block_type, environment)
  module_name = synthetic.provenance[:origin_module]
  return nil unless module_name

  module_type = Type::Combinator.nominal_of(module_name)
  RbsDispatch.try_dispatch(
    receiver: module_type, method_name: method_name, args: arg_types,
    environment: environment, block_type: block_type
  )
end

.promote_via_return_type(synthetic, environment) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 440

def promote_via_return_type(synthetic, environment)
  return_type = synthetic.return_type
  return nil if return_type.nil? || TIER_C_PLACEHOLDER_RETURNS.include?(return_type)

  environment.nominal_for_name(return_type)
end

.rbs_display_for(rbs_result) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 577

def rbs_display_for(rbs_result)
  return "untyped" if rbs_result.nil?

  rbs_result.respond_to?(:describe) ? rbs_result.describe : rbs_result.inspect
end

.rbs_result_untyped?(rbs_result) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rigor/inference/method_dispatcher.rb', line 573

def rbs_result_untyped?(rbs_result)
  rbs_result.is_a?(Type::Dynamic) && rbs_result.static_facet.is_a?(Type::Top)
end

.receiver_matches_owner?(class_name, owner, environment) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rigor/inference/method_dispatcher.rb', line 603

def receiver_matches_owner?(class_name, owner, environment)
  return true if class_name == owner

  ordering = environment.class_ordering(class_name, owner)
  %i[equal subclass].include?(ordering)
rescue StandardError
  false
end

.record_boundary_cross_if_applicable(receiver_type, method_name, rbs_result, environment) ⇒ Object

ADR-10 slice 5c — record a ‘dynamic.dependency-source.boundary-cross` event when RBS dispatch resolves a call AND the receiver class belongs to a `mode: :full` opt-in gem whose Walker also catalogued the same `(class_name, method_name)`. The dispatcher still returns the RBS answer (per ADR-10’s tier order: authoritative-source wins), but the reporter accumulates the crossing for end-of-run audit diagnostics.

Five honest fall-throughs keep the gate narrow:

  • environment / index / reporter missing — slice 5c needs all three.

  • receiver has no nominal class name (Dynamic-only carriers) — nothing to look up.

  • receiver class doesn’t belong to a ‘mode: :full` gem — the user didn’t opt this gem into the distinct dispatch path.

  • the gem-source catalog has no entry for the method —only RBS knows about it; nothing to cross.

  • the RBS-side result is itself ‘Dynamic` — the “agreement” is trivially `untyped ≈ untyped`, no meaningful divergence to flag.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 531

def record_boundary_cross_if_applicable(receiver_type, method_name, rbs_result, environment)
  class_name = boundary_cross_class_name(receiver_type, environment, rbs_result)
  return if class_name.nil?

  index = environment.dependency_source_index
  return unless index.full_mode?(class_name)
  return unless index.contribution_for(class_name: class_name, method_name: method_name)

  environment.boundary_cross_reporter.record(
    class_name: class_name, method_name: method_name,
    gem_name: index.gem_for(class_name),
    rbs_display: rbs_display_for(rbs_result)
  )
end

.static_refinement_class_for(receiver_type) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 329

def static_refinement_class_for(receiver_type)
  case receiver_type
  when Type::Singleton, Type::Nominal
    receiver_type.class_name
  end
end

.static_refinement_owner_for(receiver_type, candidates) ⇒ Object

Picks the most specific override owner the receiver honours. For Kernel-owned overrides the receiver simply needs to be a real-class Nominal / Singleton (i.e. not BasicObject and not a Dynamic / Constant / shape carrier — those carriers go through their own narrower tiers).



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# File 'lib/rigor/inference/method_dispatcher.rb', line 320

def static_refinement_owner_for(receiver_type, candidates)
  receiver_class = static_refinement_class_for(receiver_type)
  return nil unless receiver_class

  return "Kernel" if candidates.include?("Kernel") && receiver_class != "BasicObject"

  candidates.find { |owner| owner == receiver_class }
end

.synthetic_method_class_name(receiver_type) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 447

def synthetic_method_class_name(receiver_type)
  case receiver_type
  when Type::Nominal, Type::Singleton then receiver_type.class_name
  end
end

.try_dependency_source(receiver_type, method_name, environment) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 477

def try_dependency_source(receiver_type, method_name, environment)
  index = environment&.dependency_source_index
  return nil if index.nil? || index.empty?

  class_name = dep_source_class_name(receiver_type)
  return nil if class_name.nil?

  # ADR-10 5a — per-receiver plugin veto. When a
  # registered plugin declares `manifest(owns_receivers:
  # [<class>])` AND the call's receiver IS that class
  # (or a subclass), decline and let plugins handle the
  # call. Plugins that own a receiver are the
  # authoritative source for that type; gem-source
  # inference must not contribute behind their backs.
  return nil if plugin_owns_receiver?(class_name, environment)

  contribution = index.contribution_for(class_name: class_name, method_name: method_name)
  return dependency_source_return_type(contribution) if contribution

  # ADR-10 5b — β budget semantics. On a catalog miss,
  # if the receiver class belongs to a budget-exceeded
  # gem AND the user opted into `:dependency_silence`,
  # return `Dynamic[top]` rather than falling through to
  # the user-class fallback. The user-class fallback
  # would otherwise emit `call.undefined-method` for
  # methods Rigor's catalog couldn't reach because the
  # walker hit its cap.
  budget_silence_result(class_name, index, environment)
end

.try_discovered_method(receiver_type, method_name, scope) ⇒ Object

v0.1.3 — discovered-method dispatch tier. ‘scope` carries the `discovered_methods` table built once per program by `ScopeIndexer` (a `Hash[String, Hash[Symbol, :instance | :singleton]]`). When the receiver names a discovered class AND the requested method is recorded for that class’s appropriate kind, return ‘Type::Combinator.untyped` — the dispatcher cannot infer a more precise return type from the bare `def` shape, but the call site stops being a fail-soft hot spot.

Returns ‘nil` when scope / receiver class is unavailable, when the method is not in the discovered table, OR when `discovered_def_nodes` carries a re-typable body for the method (so the downstream `ExpressionTyper#try_user_method_inference` tier can re-type the body for a precise return type rather than collapsing to `Dynamic` here).

The tier does NOT gate on ‘rbs_class_known?`. RBS dispatch already had its turn upstream and returned `nil` (otherwise we wouldn’t be here). When RBS knows the class but the particular method is missing from the sig — common for internal helpers and for auto-generated stubs that emit ‘class X` without enumerating every method — falling through to the user-class fallback would mistakenly fire `call.undefined-method`. Honoring the discovered table here keeps the sibling-private call resolution working under partial RBS coverage.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 225

def try_discovered_method(receiver_type, method_name, scope)
  return nil if scope.nil?

  class_name, kind = discovered_method_lookup(receiver_type)
  return nil if class_name.nil?
  return nil unless scope.discovered_method?(class_name, method_name, kind)
  return nil if kind == :instance && scope.user_def_for(class_name, method_name)

  Type::Combinator.untyped
end

.try_hkt_builtin_return(receiver_type, method_name, arg_types, environment) ⇒ Object

ADR-2 § “Flow Contribution Bundle” / v0.1.1 Track 2 slice 7. Walks every loaded plugin’s ‘#flow_contribution_for(call_node:, scope:)` hook, collects the non-nil `FlowContribution` bundles, merges them through `FlowContribution::Merger`, and returns the merged `return_type` slot (or nil when no plugin contributed a return type).

Plugins whose hook raises have their contribution silently dropped for this call so the dispatch chain keeps moving — the run-level diagnostic envelope (per ADR-2 § “Plugin Trust and I/O Policy”) is owned by ‘Analysis::Runner#plugin_emitted_diagnostics`. ADR-20 slice 3 — looks up the receiver / method pair in Builtins::HktBuiltins::METHOD_RETURN_OVERRIDES and returns the reduced HKT type. Only fires when the receiver is a Type::Singleton (the `JSON.parse` shape) and the registry-backed reduction succeeds; returns `nil` otherwise so the dispatcher falls through to RBS.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 269

def try_hkt_builtin_return(receiver_type, method_name, arg_types, environment)
  return nil if environment.nil?
  return nil unless receiver_type.is_a?(Type::Singleton)

  Rigor::Builtins::HktBuiltins.method_return_override(
    class_name: receiver_type.class_name,
    method_name: method_name,
    kind: :singleton,
    arg_types: arg_types,
    hkt_registry: environment.hkt_registry
  )
end

.try_meta_introspection(receiver_type, method_name, arg_types = []) ⇒ Object

Slice 7 phase 8 — meta-introspection shortcuts. The default ‘Object#class` RBS return type is `Class`, but for a receiver of known nominal identity we can do better: `instance_of(Foo).class` is `Singleton` (the class object itself), which downstream dispatch uses to resolve `self.class.some_class_method`. The same logic answers `Foo.class` as `Singleton` (deliberate; calling `.class` on a class object yields `Class`, the metaclass). We also special-case `is_a?`- adjacent calls and the trivial `instance_of?(self)` later as the rule catalogue grows; for now only `class` is handled.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 739

def try_meta_introspection(receiver_type, method_name, arg_types = [])
  case method_name
  when :class then meta_class(receiver_type)
  when :new then meta_new(receiver_type, arg_types)
  end
end

.try_plugin_contribution(call_node, scope) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 336

def try_plugin_contribution(call_node, scope)
  return nil if call_node.nil? || scope.nil?

  registry = scope.environment&.plugin_registry
  return nil if registry.nil? || registry.empty?

  contributions = collect_plugin_contributions(registry, call_node, scope)
  return nil if contributions.empty?

  FlowContribution::Merger.merge(contributions).return_type
end

.try_project_patched_method(receiver_type, method_name, environment) ⇒ Object

ADR-17 slice 2 — project-side patched-method tier. Slice 3a uses the registry’s heuristic-extracted ‘return_type` (populated via the same `Analysis::DependencySourceInference::ReturnTypeHeuristic` the ADR-10 walker uses): a `def to_url; “hello”; end` patched onto `String` now resolves `s.to_url` to `Dynamic[Nominal]` instead of the pre-3a `Dynamic`. Falls back to `Dynamic` when the heuristic declined (non-literal tail expression).



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# File 'lib/rigor/inference/method_dispatcher.rb', line 462

def try_project_patched_method(receiver_type, method_name, environment)
  registry = environment&.project_patched_methods
  return nil if registry.nil? || registry.empty?

  class_name = synthetic_method_class_name(receiver_type)
  return nil if class_name.nil?

  kind = receiver_type.is_a?(Type::Singleton) ? :singleton : :instance
  entry = registry.lookup(class_name: class_name, method_name: method_name, kind: kind)
  return nil if entry.nil?
  return Type::Combinator.untyped if entry.return_type.nil?

  Type::Combinator.dynamic(entry.return_type)
end

.try_static_refinement(receiver_type, method_name, arg_types) ⇒ Object

Consults the Rigor-bundled static refinement table for a (owner-class, method-name, kind) entry. Kernel methods are mixed into every non-BasicObject class, so an implicit-self ‘__dir__` call (receiver_type = Nominal) is matched by looking up Kernel as the owner. Explicit `Kernel.__dir__` (receiver_type = Singleton) and instance-side calls (receiver_type = Nominal) share the `:both` row.

The receiver-side ancestor check is intentionally cheap: any non-BasicObject Nominal / Singleton matches every Kernel-owned override. BasicObject explicitly excludes Kernel and is therefore rejected. The narrow risk of a user-defined ‘def __dir__` shadowing Kernel’s method would also alter the runtime answer; users with that configuration opt out via a ‘signature_paths` overlay declaring their own return type.



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# File 'lib/rigor/inference/method_dispatcher.rb', line 299

def try_static_refinement(receiver_type, method_name, arg_types)
  candidates = Rigor::Builtins::StaticReturnRefinements.owners_for(method_name)
  return nil if candidates.empty?

  owner = static_refinement_owner_for(receiver_type, candidates)
  return nil unless owner

  kind = receiver_type.is_a?(Type::Singleton) ? :singleton : :instance
  Rigor::Builtins::StaticReturnRefinements.lookup(
    owner_class_name: owner,
    method_name: method_name,
    kind: kind,
    arg_types: arg_types
  )
end

.try_synthetic_method(receiver_type, method_name, arg_types, block_type, environment) ⇒ Object

ADR-10 slice 2b-ii. Consults the per-run ‘Analysis::DependencySourceInference::Index` carried by the environment for `(class_name, method_name)` observations harvested from opt-in gems’ ‘roots:`. On a hit, returns `Combinator.untyped` so the call site carries the `Dynamic` provenance (per ADR-10’s “Inference contract”: gem-source-inferred shapes never publish as ground-truth ‘T`). Returns `nil` when the environment carries no index, the index has no entry, or the receiver has no nominal class to look up. ADR-16 synthetic-method tier. Slice 2b shipped the floor —a match short-circuits at the right precedence (above dep-source / discovered / user-class-fallback; below RBS) and returns `Dynamic`. Slice 6 (precision promotion):

  • Tier B path (slice 6a, ‘provenance` recorded by the slice-3b scanner): redispatch on `Nominal` via `RbsDispatch` so the module’s authored RBS return type wins. Devise’s ‘valid_password?` returns `bool`, not `Dynamic`.

  • Tier C path (slice 6b, plain ‘return_type:` string from the manifest’s emit table): look up ‘environment.nominal_for_name(return_type)` so `attribute :avatar, Types::String` emits a synthetic reader returning `Nominal` (when the class is in RBS). Unparameterised class names only — parameterised forms (`Array`, `Hash[K, V]`) and plugin-supplied utility-type names (`Pick<T, K>`) require routing through the full ADR-13 `Plugin::TypeNodeResolver` chain, which slice 6 does not yet wire in (the resolver chain is consulted only for `%arigor:v1:…` payloads as of ADR-13 slice 3).



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# File 'lib/rigor/inference/method_dispatcher.rb', line 379

def try_synthetic_method(receiver_type, method_name, arg_types, block_type, environment)
  index = environment&.synthetic_method_index
  return nil if index.nil? || index.empty?

  class_name = synthetic_method_class_name(receiver_type)
  return nil if class_name.nil?

  matches = case receiver_type
            when Type::Singleton then index.lookup_singleton(class_name, method_name)
            else index.lookup_instance(class_name, method_name)
            end
  return nil if matches.empty?

  promoted = promote_synthetic_match(matches, method_name, arg_types, block_type, environment)
  promoted || Type::Combinator.untyped
end

.try_user_class_fallback(receiver_type, method_name, arg_types, environment, block_type, call_node = nil) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 654

def try_user_class_fallback(receiver_type, method_name, arg_types, environment, block_type, call_node = nil)
  return nil if environment.nil?

  fallback_receiver = user_class_fallback_receiver(receiver_type, environment)
  return nil if fallback_receiver.nil?

  # Preserve the ORIGINAL receiver type as the `self`
  # substitution so `Kernel#dup: () -> self` and other
  # `self`-returning methods route through Object's RBS
  # while still returning the caller's type rather than
  # `Object`. Without this, `base = self.dup` inside a
  # `Bundler::URI::Generic` instance method types `base`
  # as `Object` because `Bundler::URI::Generic` is not in
  # RBS and the fallback's `self` resolves to Object.
  #
  # `public_only:` — when the call has an EXPLICIT, non-`self`
  # receiver (`Favourite.select(...)`), suppress the private
  # `Object`/`Kernel`/`Class` methods the fallback would
  # otherwise resolve. Ruby raises `NoMethodError` for a
  # private method called with an explicit receiver, so
  # resolving `Favourite.select` to the private `Kernel#select`
  # (`-> Array[String]`) is a confidently-wrong type. Implicit-
  # self / `self.`-receiver calls (`puts`, `raise`, `require`)
  # keep resolving — those are the fallback's intended targets.
  RbsDispatch.try_dispatch(
    receiver: fallback_receiver,
    method_name: method_name,
    args: arg_types,
    environment: environment,
    block_type: block_type,
    self_type_override: receiver_type,
    public_only: explicit_non_self_receiver?(call_node)
  )
end

.user_class_fallback_receiver(receiver_type, environment) ⇒ Object 



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# File 'lib/rigor/inference/method_dispatcher.rb', line 706

def user_class_fallback_receiver(receiver_type, environment)
  case receiver_type
  when Type::Nominal
    # Modules: even when RBS knows the module, an instance
    # method on a mixin-only module (e.g. `PP::ObjectMixin`)
    # observes Kernel / Object methods through every concrete
    # includer's ancestor chain. Route through the
    # `Nominal[Object]` fallback so `self.inspect` /
    # `self.respond_to?` / `self.class` resolve cleanly when
    # the module itself does not declare them.
    known = Rigor::Reflection.rbs_class_known?(receiver_type.class_name, environment: environment)
    return environment.nominal_for_name("Object") if !known || environment.rbs_module?(receiver_type.class_name)

    nil
  when Type::Singleton
    return nil if Rigor::Reflection.rbs_class_known?(receiver_type.class_name, environment: environment)

    environment.singleton_for_name("Class")
  end
end