Remove support for passing nil to IO#ungetc

Fixes [Bug #13675]

1 files changed, 13 insertions, 4 deletions

diff --git a/spec/ruby/core/io/ungetc_spec.rb b/spec/ruby/core/io/ungetc_spec.rb
index 34d4caf745..4be0e3aa8b 100644
--- a/spec/ruby/core/io/ungetc_spec.rb
+++ b/spec/ruby/core/io/ungetc_spec.rb
@@ -103,10 +103,19 @@ describe "IO#ungetc" do
     -> { @io.sysread(1) }.should raise_error(IOError)
   end
 
-  it "does not affect the stream and returns nil when passed nil" do
-    @io.getc.should == ?V
-    @io.ungetc(nil)
-    @io.getc.should == ?o
+  ruby_version_is "0"..."2.8" do
+    it "does not affect the stream and returns nil when passed nil" do
+      @io.getc.should == ?V
+      @io.ungetc(nil)
+      @io.getc.should == ?o
+    end
+  end
+
+  ruby_version_is "2.8" do
+    it "raises TypeError if passed nil" do
+      @io.getc.should == ?V
+      proc{@io.ungetc(nil)}.should raise_error(TypeError)
+    end
   end
 
   it "puts one or more characters back in the stream" do