Merge pull request #2745 from vpellan/vpellan/caller-locations-narrowing

[Kernel] Narrow `caller_locations`

Author: ksss

core/kernel.rbs

@@ -204,8 +204,9 @@ module Kernel : BasicObject
   # Optionally you can pass a range, which will return an array containing the
   # entries within the specified range.
   #
-  def self?.caller_locations: (?Integer start_or_range, ?Integer length) -> ::Array[Thread::Backtrace::Location]?
-                            | (?::Range[Integer] start_or_range) -> ::Array[Thread::Backtrace::Location]?
+  def self?.caller_locations: (Integer start_or_range, ?Integer length) -> ::Array[Thread::Backtrace::Location]?
+                            | (::Range[Integer] start_or_range) -> ::Array[Thread::Backtrace::Location]?
+                            | () -> ::Array[Thread::Backtrace::Location]
 
   # <!--
   #   rdoc-file=vm_eval.c

test/stdlib/Kernel_test.rb

@@ -7,6 +7,20 @@ class KernelSingletonTest < Test::Unit::TestCase
 
   testing "singleton(::Kernel)"
 
+  def test_caller_locations
+    assert_send_type "() -> Array[Thread::Backtrace::Location]",
+                     Kernel, :caller_locations
+
+    assert_send_type "(Integer) -> Array[Thread::Backtrace::Location]?",
+                      Kernel, :caller_locations, 1
+
+    assert_send_type "(Integer, Integer) -> Array[Thread::Backtrace::Location]?",
+                      Kernel, :caller_locations, 1, 2
+
+    assert_send_type "(::Range[Integer]) -> Array[Thread::Backtrace::Location]?",
+                     Kernel, :caller_locations, (1..3)
+  end
+
   def test_Array
     assert_send_type "(nil) -> []",
                      Kernel, :Array, nil