Fix issue with quarantined specs for #syntax_tree

Author: andrykonchin

core/proc/fixtures/syntax_tree.rb

@@ -0,0 +1,14 @@
+# Avoids warnings on Ruby 3.3
+module ProcSpecs
+  module SyntaxTree
+    def self.lambda_it
+      -> { it }
+    end
+    LAMBDA_IT_LINE = __LINE__ - 2
+
+    def self.proc_it
+      proc { it }
+    end
+    PROC_IT_LINE = __LINE__ - 2
+  end
+end

core/proc/syntax_tree_spec.rb

@@ -2,6 +2,8 @@
 require_relative '../../fixtures/source_range_helpers'
 
 ruby_version_is "4.1" do
+  require_relative 'fixtures/syntax_tree' # avoids warnings on Ruby 3.3
+
   describe "Proc#syntax_tree" do
     before :each do
       skip "parse.y" unless syntax_tree_returns_prism_node
@@ -38,26 +40,24 @@ def return_block(&b)
       node.should.is_a?(Ruby::Prism::LambdaNode)
     end
 
-    quarantine! do # NoMethodError: undefined method 'start_line' for nil
     it "does not return implicit parameter nodes" do
       # Interesting because the BlockNode and the ItParametersNode/NumberedParametersNode are fully overlapping
-      node = eval('-> { it }.syntax_tree') # emits a warning on Ruby 3.3
-      node.start_line.should == __LINE__ - 1
+      node = ProcSpecs::SyntaxTree.lambda_it.syntax_tree
+      node.start_line.should == ProcSpecs::SyntaxTree::LAMBDA_IT_LINE
       node.should.is_a?(Ruby::Prism::LambdaNode)
 
       node = -> { _1 }.syntax_tree
       node.start_line.should == __LINE__ - 1
       node.should.is_a?(Ruby::Prism::LambdaNode)
 
-      node = eval('proc { it }.syntax_tree') # emits a warning on Ruby 3.3
-      node.start_line.should == __LINE__ - 1
+      node = ProcSpecs::SyntaxTree.proc_it.syntax_tree
+      node.start_line.should == ProcSpecs::SyntaxTree::PROC_IT_LINE
       node.should.is_a?(Ruby::Prism::CallNode)
 
       node = proc { _1 }.syntax_tree
       node.start_line.should == __LINE__ - 1
       node.should.is_a?(Ruby::Prism::CallNode)
     end
-    end
 
     it "returns a ForNode for a for-loop block" do
       iter = Object.new