From 49593f87b10cf8cb87405c3fb75917c84cb64135 Mon Sep 17 00:00:00 2001
From: SamW <mail@sampersand.me>
Date: Fri, 17 Oct 2025 19:05:30 -0700
Subject: [PATCH] [Kernel] Add tests for Exiting and Exception functions

---
 core/kernel.rbs                      |   2 +-
 lib/rbs/unit_test/type_assertions.rb |  25 +++++
 sig/unit_test/type_assertions.rbs    |  11 ++
 test/stdlib/Kernel_test.rb           | 144 +++++++++++++++++++++++++++
 4 files changed, 181 insertions(+), 1 deletion(-)

diff --git a/core/kernel.rbs b/core/kernel.rbs
index b50e58111..7e67cf811 100644
--- a/core/kernel.rbs
+++ b/core/kernel.rbs
@@ -1004,7 +1004,7 @@ module Kernel : BasicObject
   #
   def self?.fail: () -> bot
                 | (string message, ?cause: Exception?) -> bot
-                | (_Exception exception, ?_ToS? message, ?String | Array[String] | Array[Thread::Backtrace::Location] | nil backtrace, ?cause: Exception?) -> bot
+                | (_Exception exception, ?string | _ToS message, ?String | Array[String] | Array[Thread::Backtrace::Location] | nil backtrace, ?cause: Exception?) -> bot
                 | (_Exception exception, ?cause: Exception?, **untyped) -> bot
 
   # <!--
diff --git a/lib/rbs/unit_test/type_assertions.rb b/lib/rbs/unit_test/type_assertions.rb
index d274343fa..44847ef0c 100644
--- a/lib/rbs/unit_test/type_assertions.rb
+++ b/lib/rbs/unit_test/type_assertions.rb
@@ -192,6 +192,31 @@ def send_setup(method_type, receiver, method, args, proc)
         end
       end
 
+      ruby2_keywords def assert_send_type_error(method_type, error_type, receiver, method, *args, &block)
+        send_setup(method_type, receiver, method, args, block) do |method_type, trace, result, exception|
+          typecheck = RBS::Test::TypeCheck.new(
+            self_class: receiver.class,
+            builder: builder,
+            sample_size: 100,
+            unchecked_classes: [],
+            instance_class: instance_class,
+            class_class: class_class
+          )
+          errors = typecheck.method_call(method, method_type, trace, errors: [])
+
+          assert_empty errors.map {|x| RBS::Test::Errors.to_string(x) }, "Call trace does not match with given method type: #{trace.inspect}"
+
+          method_defs = method_defs(method)
+          all_errors = method_defs.map {|t| typecheck.method_call(method, t.type, trace, errors: [], annotations: t.each_annotation.to_a) }
+          assert all_errors.any? {|es| es.empty? }, "Call trace does not match one of method definitions:\n  #{trace.inspect}\n  #{method_defs.map(&:type).join(" | ")}"
+
+          # Use `instnace_of?` instead of `is_a?` as we want to check for _the exact exception class_.
+          assert exception.instance_of? error_type
+
+          result
+        end
+      end
+
       ruby2_keywords def refute_send_type(method_type, receiver, method, *args, &block)
         send_setup(method_type, receiver, method, args, block) do |method_type, trace, result, exception|
           method_type = method_type.update(
diff --git a/sig/unit_test/type_assertions.rbs b/sig/unit_test/type_assertions.rbs
index 3fb1ed9fd..9e7d32fc5 100644
--- a/sig/unit_test/type_assertions.rbs
+++ b/sig/unit_test/type_assertions.rbs
@@ -153,6 +153,17 @@ module RBS
       #
       def refute_send_type: (String | MethodType method_type, untyped receiver, Symbol method_name, *untyped args) ?{ () -> untyped } -> void
 
+      # Calls a method `method_name`, validates if it's compatible with RBS type definition, and ensures it raises the `exception` class.
+      #
+      # 1. It calls `method_name` with `receiver` passing `args` and given block,
+      # 2. Validates if it's compatible with given `method_type`, and
+      # 3. Validates if it's compatible with one of the overloads defined in RBS type definition
+      # 4. Ensures that `exception` is thrown
+      #
+      # See `assert_send_type` for the details.
+      #
+      def assert_send_type_error: (String | MethodType method_type, Class exception, untyped receiver, Symbol method_name, *untyped args) ?{ () -> untyped } -> void
+
       # Asserts if the constant `constant_name` has `constant_type`, and the RBS definition has compatible type
       #
       # ```ruby
diff --git a/test/stdlib/Kernel_test.rb b/test/stdlib/Kernel_test.rb
index 1af2bf0dd..3e6c2a20e 100644
--- a/test/stdlib/Kernel_test.rb
+++ b/test/stdlib/Kernel_test.rb
@@ -81,6 +81,150 @@ def test_String
                      Kernel, :String, ToS.new
   end
 
+  def test_abort
+    old_stderr = $stderr
+    $stderr = File.open(File::NULL, 'w')
+
+    assert_send_type_error '() -> bot', SystemExit,
+                           Kernel, :abort
+
+    with_string 'oops' do |message|
+      assert_send_type_error '(string) -> bot', SystemExit,
+                             Kernel, :abort, message
+    end
+  ensure
+    $stderr.close rescue nil
+    $stderr = old_stderr
+  end
+
+  def test_exit
+    assert_send_type_error '() -> bot', SystemExit,
+                           Kernel, :exit
+
+    with_int.and with_bool do |status|
+      assert_send_type_error '(int | bool) -> bot', SystemExit,
+                             Kernel, :exit, status
+    end
+  end
+
+  def test_exit!
+    # Sadly can't use `assert_send_type_error`, so we use exit status to check.
+    _, status = Process.wait2(Process.spawn(RUBY_EXECUTABLE, '--disable=all', '-e', 'exit!; exit(80)'))
+    assert_equal 1, status.exitstatus
+
+    _, status = Process.wait2(Process.spawn(RUBY_EXECUTABLE, '--disable=all', '-e', 'exit!(true); exit(80)'))
+    assert_equal 0, status.exitstatus
+
+    _, status = Process.wait2(Process.spawn(RUBY_EXECUTABLE, '--disable=all', '-e', 'exit!(false); exit(80)'))
+    assert_equal 1, status.exitstatus
+
+    _, status = Process.wait2(Process.spawn(RUBY_EXECUTABLE, '--disable=all', '-e', 'exit!(12); exit(80)'))
+    assert_equal 12, status.exitstatus
+
+    _, status = Process.wait2(Process.spawn(RUBY_EXECUTABLE, '--disable=all', '-e', <<~'RUBY'))
+      # hardcode a "blank slate" object in
+      class ToInt < BasicObject
+        instance_methods.each do |im|
+          next if im == :__id__
+          next if im == :__send__
+          undef_method im
+        end
+
+        def to_int = 12
+      end
+
+      exit!(ToInt.new)
+      exit(80)
+    RUBY
+    assert_equal 12, status.exitstatus
+  end
+
+  def test_at_exit
+    assert_send_type "() { () -> void } -> Proc",
+                     Kernel, :at_exit do end
+  end
+
+  def test_catch
+    assert_send_type "() { (Object) -> untyped } -> untyped",
+                     Kernel, :catch do end
+    assert_send_type "[T] (T) { (T) -> untyped } -> untyped",
+                     Kernel, :catch, Object.new do end
+  end
+
+  def test_throw
+    # Make sure it requires an arg
+    refute_send_type "() -> bot",
+                     Kernel, :throw
+
+    with_untyped do |tag|
+      assert_send_type_error '(untyped) -> bot', UncaughtThrowError,
+                             Kernel, :throw, tag
+      with_untyped do |obj|
+        assert_send_type_error '(untyped, untyped) -> bot', UncaughtThrowError,
+                               Kernel, :throw, tag, obj
+      end
+    end
+  end
+
+  TestException = Class.new(Exception)
+
+  def test_raise(method: :raise)
+    assert_send_type_error '() -> bot', RuntimeError,
+                           Kernel, method
+
+    cause = TestException.new
+
+    with_string do |message|
+      assert_send_type_error '(string) -> bot', RuntimeError,
+                             Kernel, method, message
+      assert_send_type_error '(string, cause: nil) -> bot', RuntimeError,
+                             Kernel, method, message, cause: nil
+      assert_send_type_error '(string, cause: Exception) -> bot', RuntimeError,
+                             Kernel, method, message, cause: cause
+    end
+
+    exception = BlankSlate.new
+    def exception.exception(mesasage = nil) = TestException.new
+
+    assert_send_type_error '(_Exception) -> bot', TestException,
+                           Kernel, method, exception
+    assert_send_type_error '(_Exception, cause: nil) -> bot', TestException,
+                           Kernel, method, exception, cause: nil
+    assert_send_type_error '(_Exception, cause: Exception) -> bot', TestException,
+                           Kernel, method, exception, cause: cause
+
+    with_string.and ToS.new, nil do |message|
+      assert_send_type_error '(_Exception, string | _ToS) -> bot', TestException,
+                             Kernel, method, exception, message
+      assert_send_type_error '(_Exception, string | _ToS, cause: nil) -> bot', TestException,
+                             Kernel, method, exception, message, cause: nil
+      assert_send_type_error '(_Exception, string | _ToS, cause: Exception) -> bot', TestException,
+                             Kernel, method, exception, message, cause: cause
+
+      with "bt", caller, caller_locations, nil do |backtrace|
+        assert_send_type_error '(_Exception, string | _ToS, String | Array[String] | Array[Thread::Backtrace::Location] | nil) -> bot', TestException,
+                               Kernel, method, exception, message, backtrace
+        assert_send_type_error '(_Exception, string | _ToS, String | Array[String] | Array[Thread::Backtrace::Location] | nil, cause: nil) -> bot', TestException,
+                               Kernel, method, exception, message, backtrace, cause: nil
+        assert_send_type_error '(_Exception, string | _ToS, String | Array[String] | Array[Thread::Backtrace::Location] | nil, cause: Exception) -> bot', TestException,
+                               Kernel, method, exception, message, backtrace, cause: cause
+      end
+    end
+
+    with_untyped do |value|
+      assert_send_type_error '(_Exception, **untyped) -> bot', TestException,
+                             Kernel, method, exception, key: value
+      assert_send_type_error '(_Exception, cause: nil, **untyped) -> bot', TestException,
+                             Kernel, method, exception, cause: nil, key: value
+      assert_send_type_error '(_Exception, cause: Exception, **untyped) -> bot', TestException,
+                             Kernel, method, exception, cause: cause, key: value
+    end
+  end
+
+  def test_fail
+    test_raise method: :fail
+  end
+
   def test_autoload?
     with_interned :TestModuleForAutoload do |interned|
       assert_send_type "(::interned) -> String?",