Make RubyVM::AbstractSyntaxTree.of raise for method/proc created in eval

This changes Thread::Location::Backtrace#absolute_path to return
nil for methods/procs defined in eval.  If the realpath of an iseq
is nil, that indicates it was defined in eval, in which case you
cannot use RubyVM::AbstractSyntaxTree.of.

Fixes [Bug #16983]

Co-authored-by: Koichi Sasada <ko1@atdot.net>

1 files changed, 14 insertions, 4 deletions

diff --git a/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb b/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb
index b0ae28beee..4136f09348 100644
--- a/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb
+++ b/spec/ruby/core/thread/backtrace/location/absolute_path_spec.rb
@@ -18,10 +18,20 @@ describe 'Thread::Backtrace::Location#absolute_path' do
   end
 
   context "when used in eval with a given filename" do
-    it "returns filename" do
-      code = "caller_locations(0)[0].absolute_path"
-      eval(code, nil, "foo.rb").should == "foo.rb"
-      eval(code, nil, "foo/bar.rb").should == "foo/bar.rb"
+    code = "caller_locations(0)[0].absolute_path"
+
+    ruby_version_is ""..."3.1" do
+      it "returns filename with absolute_path" do
+        eval(code, nil, "foo.rb").should == "foo.rb"
+        eval(code, nil, "foo/bar.rb").should == "foo/bar.rb"
+      end
+    end
+
+    ruby_version_is "3.1" do
+      it "returns nil with absolute_path" do
+        eval(code, nil, "foo.rb").should == nil
+        eval(code, nil, "foo/bar.rb").should == nil
+      end
     end
   end