Fix type inference for Class.new assigned to constants

lib/typeprof/core/ast/const.rb

@@ -112,10 +112,30 @@ def install0(genv)
         @cpath.install(genv) if @cpath
         val = @rhs.install(genv)
         if @static_cpath
-          @changes.add_edge(genv, val, @static_ret.vtx)
+          if detect_class_new?(@rhs)
+            # Create a module entity for the dynamically created class
+            mod = genv.resolve_cpath(@static_cpath)
+
+            # Create singleton type for the new class
+            singleton_ty = Type::Singleton.new(genv, mod)
+            vtx = Source.new(singleton_ty)
+            @changes.add_edge(genv, vtx, @static_ret.vtx)
+          else
+            @changes.add_edge(genv, val, @static_ret.vtx)
+          end
         end
         val
       end
+
+      private
+
+      def detect_class_new?(node)
+        node.is_a?(CallBaseNode) &&
+          node.mid == :new &&
+          node.recv.is_a?(ConstantReadNode) &&
+          node.recv.cname == :Class &&
+          node.recv.cbase.nil?
+      end
     end
   end
 end

scenario/control/rescue-assign-with-class-new.rb

@@ -0,0 +1,15 @@
+## update: my_error.rb
+MyError = Class.new(StandardError)
+
+## update: test.rb
+class C
+  def foo
+  rescue MyError => e
+    raise ArgumentError, e.message
+  end
+end
+
+## assert: test.rb
+class C
+  def foo: -> nil
+end