[NSTextStorage readFromURL:options:documentAttributes:error]

[nickasd]

The converted code generates the compiler error Cannot invoke 'read' with an argument list of type '(from: URL, options: [NSAttributedString.DocumentReadingOptionKey : String], documentAttributes: inout [AnyHashable : Any])'.
http://swiftify.me/8oosqh

[tomattoz]

We need intermediate variable here, like this:

        let textStorage: NSTextStorage? = nil
        var documentAttributes: [AnyHashable : Any]?

        do {
            if let url = url {
                var nsDictionary: NSDictionary?
                
                try textStorage?.read(from: url, options: [
                    NSAttributedString.DocumentReadingOptionKey.documentType: NSAttributedString.DocumentType.plain
                ], documentAttributes: &nsDictionary)
                
                documentAttributes = nsDictionary as? [AnyHashable : Any]
            }
        } catch {
        }

But it looks like this is impossible to do in metadata. @alex-swiftify what do you think?

[tomattoz]

Also we can solve this by cancelling conversion of NSDictionary to swift dictionary if explicitly need NSDictionary somewhere in method calls. And the same for another types like NSArray, NSError ...

[alex-swiftify]

@tomattoz I agree that looks difficult.
You could try generating multiple lines of code via metadata translations by adding \n or \t characters, but the [_textStorage readFromURL] method has a return value and that could be problematic if this call is nested.
You can still give that a try anyway - providing it works for 80% of cases and don't take "hours" of work.

We already have similar reports like https://swiftify.atlassian.net/browse/SWC-875 but they look difficult.

[alex-swiftify]

Also we can solve this by cancelling conversion of NSDictionary to swift dictionary if explicitly need NSDictionary somewhere in method calls. And the same for another types like NSArray, NSError ...

This looks like the way to go here.
There are some existing mappings that cast back to NSArray/NSString/NSDictionary and call their methods.
Try reusing that approach.