Proc.new: change deprecation warning for clarity (issue #15539)

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67519 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

proc.c

@@ -710,7 +710,7 @@ proc_new(VALUE klass, int8_t is_lambda)
                 rb_raise(rb_eArgError, proc_without_block);
             }
             else {
-		rb_warn(proc_without_block);
+		rb_warn("Capturing the given block using Proc.new is deprecated; use `&block` instead");
 	    }
 	}
 #else

spec/ruby/core/kernel/proc_spec.rb

@@ -56,7 +56,7 @@ describe "Kernel#proc" do
 
       -> {
         some_method { "hello" }
-      }.should complain(/tried to create Proc object without a block/)
+      }.should complain(/Capturing the given block using Proc.new is deprecated/)
     end
   end
 

spec/ruby/core/proc/new_spec.rb

@@ -194,11 +194,11 @@ describe "Proc.new without a block" do
 
   ruby_version_is "2.7" do
     it "can be created if invoked from within a method with a block" do
-      lambda { ProcSpecs.new_proc_in_method { "hello" } }.should complain(/tried to create Proc object without a block/)
+      lambda { ProcSpecs.new_proc_in_method { "hello" } }.should complain(/Capturing the given block using Proc.new is deprecated/)
     end
 
     it "can be created if invoked on a subclass from within a method with a block" do
-      lambda { ProcSpecs.new_proc_subclass_in_method { "hello" } }.should complain(/tried to create Proc object without a block/)
+      lambda { ProcSpecs.new_proc_subclass_in_method { "hello" } }.should complain(/Capturing the given block using Proc.new is deprecated/)
     end
 
 
@@ -209,7 +209,7 @@ describe "Proc.new without a block" do
 
       -> {
         some_method { "hello" }
-      }.should complain(/tried to create Proc object without a block/)
+      }.should complain(/Capturing the given block using Proc.new is deprecated/)
     end
   end
 end