BUG: CC0091 (make static) changes references incorrectly when used as a method group and in conjunction with another method invocation

[jakubsuchybio]

This is producing an incorrect fix:

class Bar
{
    void ShouldBeStatic()
    {
    }
    void Caller()
    {
        Foo.M(new Baz(ShouldBeStatic));
    }
}
class Foo
{
    public static void M(Baz b) { }
}
class Baz
{
    public Baz(Action a)
    {
    }
}

This is the current fix, broken (other classes omitted):

class Bar
{
    static void ShouldBeStatic()
    {
    }
    void Caller()
    {
        M(new Baz(ShouldBeStatic));
    }
}

This is the expected fix (other classes omitted, only static added to method, nothing else changed):

class Bar
{
    static void ShouldBeStatic()
    {
    }
    void Caller()
    {
        Foo.M(new Baz(ShouldBeStatic));
    }
}

Here is the original description from @jakubsuchybio:

I found another error in CC0091 which somehow changes another method.
Dunno why it is changing things in another method not related to the changed method.

        private void ResetButton_Confirm(Gump sender, bool response)
        {
            if( response )
            {
                PerConfig.DefaultMacros();
                MacroProvider.InstanceIndex = 0;
            }

            GMacroEditorForm.Open();
        }

        private void ResetButton_OnClick(Gump g)
        {
            this.Close();
            Gumps.Desktop.Children.Add( new GMessageBoxYesNo(
                ClientLocalization.GetString( "#319#Smazat všechna\rvlastní makra?" ),
                true,
                ResetButton_Confirm ) );
        }

Translates into:

        private static void ResetButton_Confirm(Gump sender, bool response)
        {
            if( response )
            {
                PerConfig.DefaultMacros();
                MacroProvider.InstanceIndex = 0;
            }

            GMacroEditorForm.Open();
        }

        private void ResetButton_OnClick(Gump g)
        {
            this.Close();
            Add( new GMessageBoxYesNo(
                            ClientLocalization.GetString( "#319#Smazat všechna\rvlastní makra?" ),
                            true,
                            ResetButton_Confirm ) );
        }

Here is a picture of preview:

Another occurence of this bug here:

        private void Export(string fileName)
        {
            var dialog = new System.Windows.Forms.SaveFileDialog
            {
                FileName = "mwmakra.mul",
                InitialDirectory = Environment.GetFolderPath( System.Environment.SpecialFolder.MyDocuments )
            };

            var result = dialog.ShowDialog();
            if( result == System.Windows.Forms.DialogResult.OK )
            {
                System.IO.File.Copy( fileName, dialog.FileName, true );
            }
            System.IO.File.Delete( fileName );
        }

        private void ExportButton_OnClick(Gump g)
        {
            var fileName = System.IO.Path.GetTempFileName();
            this.Close();
            MacroProvider.Export( fileName );
            GSystemDialogWaiter<string>.Run( Export, fileName, ExportCompleted );
        }

Translates into:

        private static void Export(string fileName)
        {
            var dialog = new System.Windows.Forms.SaveFileDialog
            {
                FileName = "mwmakra.mul",
                InitialDirectory = Environment.GetFolderPath( System.Environment.SpecialFolder.MyDocuments )
            };

            var result = dialog.ShowDialog();
            if( result == System.Windows.Forms.DialogResult.OK )
            {
                System.IO.File.Copy( fileName, dialog.FileName, true );
            }
            System.IO.File.Delete( fileName );
        }

        private void ExportButton_OnClick(Gump g)
        {
            var fileName = System.IO.Path.GetTempFileName();
            this.Close();
            MacroProvider.Export( fileName );
            Run( Export, fileName, ExportCompleted );
        }

Here is a picture of preview of second occurence:

I would post you my whole codebase to test it on it, if you couldn't find a code proof, but this project is not open and my employer wouldn't like it.

[giggio]

@jakubsuchybio bug confirmed, I have narrowed it down to a simpler case. Thanks for the report.

[martinzimmermann]

@giggio my pull request also fixes this issue