3 files changed, 38 insertions, 8 deletions
diff --git a/test/ruby/test_jit.rb b/test/ruby/test_jit.rb
index f7ea67c023..dcbe694d7a 100644
--- a/test/ruby/test_jit.rb
+++ b/test/ruby/test_jit.rb
@@ -243,8 +243,8 @@ class TestJIT < Test::Unit::TestCase
     end;
   end
 
-  def test_compile_insn_putstring_concatstrings_tostring
-    assert_compile_once('"a#{}b" + "c"', result_inspect: '"abc"', insns: %i[putstring concatstrings tostring])
+  def test_compile_insn_putstring_concatstrings_objtostring
+    assert_compile_once('"a#{}b" + "c"', result_inspect: '"abc"', insns: %i[putstring concatstrings objtostring])
   end
 
   def test_compile_insn_toregexp
@@ -482,8 +482,8 @@ class TestJIT < Test::Unit::TestCase
     end;
   end
 
-  def test_compile_insn_checktype
-    assert_compile_once("#{<<~"begin;"}\n#{<<~'end;'}", result_inspect: '"42"', insns: %i[checktype])
+  def test_compile_insn_objtostring
+    assert_compile_once("#{<<~"begin;"}\n#{<<~'end;'}", result_inspect: '"42"', insns: %i[objtostring])
     begin;
       a = '2'
       "4#{a}"
diff --git a/test/ruby/test_optimization.rb b/test/ruby/test_optimization.rb
index cbae6d5e8c..a834996788 100644
--- a/test/ruby/test_optimization.rb
+++ b/test/ruby/test_optimization.rb
@@ -903,4 +903,34 @@ class TestRubyOptimization < Test::Unit::TestCase
       raise  "END"
     end;
   end
+
+  class Objtostring
+  end
+
+  def test_objtostring
+    assert_raise(NoMethodError){"#{BasicObject.new}"}
+    assert_redefine_method('Symbol', 'to_s', <<-'end')
+      assert_match %r{\A#<Symbol:0x[0-9a-f]+>\z}, "#{:foo}"
+    end
+    assert_redefine_method('NilClass', 'to_s', <<-'end')
+      assert_match %r{\A#<NilClass:0x[0-9a-f]+>\z}, "#{nil}"
+    end
+    assert_redefine_method('TrueClass', 'to_s', <<-'end')
+      assert_match %r{\A#<TrueClass:0x[0-9a-f]+>\z}, "#{true}"
+    end
+    assert_redefine_method('FalseClass', 'to_s', <<-'end')
+      assert_match %r{\A#<FalseClass:0x[0-9a-f]+>\z}, "#{false}"
+    end
+    assert_redefine_method('Integer', 'to_s', <<-'end')
+      (-1..10).each { |i|
+        assert_match %r{\A#<Integer:0x[0-9a-f]+>\z}, "#{i}"
+      }
+    end
+    assert_equal "TestRubyOptimization::Objtostring", "#{Objtostring}"
+    assert_match %r{\A#<Class:0x[0-9a-f]+>\z}, "#{Class.new}"
+    assert_match %r{\A#<Module:0x[0-9a-f]+>\z}, "#{Module.new}"
+    o = Object.new
+    def o.to_s; 1; end
+    assert_match %r{\A#<Object:0x[0-9a-f]+>\z}, "#{o}"
+  end
 end
diff --git a/test/ruby/test_yjit.rb b/test/ruby/test_yjit.rb
index f0d899e908..9cb727eae1 100644
--- a/test/ruby/test_yjit.rb
+++ b/test/ruby/test_yjit.rb
@@ -215,7 +215,7 @@ class TestYJIT < Test::Unit::TestCase
 
   def test_compile_tostring
     assert_no_exits('"i am a string #{true}"')
-  end
+  end if false # Until objtostring supported
 
   def test_compile_opt_aset
     assert_compiles('[1,2,3][2] = 4', insns: %i[opt_aset])
@@ -240,7 +240,7 @@ class TestYJIT < Test::Unit::TestCase
 
   def test_compile_regexp
     assert_no_exits('/#{true}/')
-  end
+  end if false # Until objtostring supported
 
   def test_getlocal_with_level
     assert_compiles(<<~RUBY, insns: %i[getlocal opt_plus], result: [[7]])
@@ -385,7 +385,7 @@ class TestYJIT < Test::Unit::TestCase
       make_str("foo", "bar")
       make_str("foo", "bar")
     RUBY
-  end
+  end if false # Until objtostring supported
 
   def test_string_interpolation_cast
     assert_compiles(<<~'RUBY', insns: %i[checktype concatstrings tostring], result: "123")
@@ -395,7 +395,7 @@ class TestYJIT < Test::Unit::TestCase
 
       make_str(1, 23)
     RUBY
-  end
+  end if false # Until objtostring supported
 
   def test_checkkeyword
     assert_compiles(<<~'RUBY', insns: %i[checkkeyword], result: [2, 5])