[SourceKit] add qualified types in type requests

[skrtks]

This adds the fully qualified type to the response of expression and variable type requests in SourceKit.

The qualified type can be accessed through the <key.expression_qualified_type> and <key.variable_qualified_type> keys in the response of the expression and variable type requests.

[skrtks]

@ahoppen do you perhaps know who would be the right person to ask as a reviewer here?

[ahoppen]

Looks good to me in general. A couple conceptual questions:

• What’s the reason you went for a fully-qualified type instead of a USR? Is it because fully-qualified types are easier to parse than USRs?
• I’m thinking whether sending back the fully-qualified types might blow up the response and if we should add an option to the request to control whether fully-qualified types are sent. I don’t have strong opinions either way but @rintaro might.

[skrtks]

Thanks for the quick response!

What’s the reason you went for a fully-qualified type instead of a USR? Is it because fully-qualified types are easier to parse than USRs?

To give you some context, we would like to use this to improve Swift support in JetBrains IDE's. I considered the USR, but since we have everything in place for parsing type strings to our internal type representation, this seemed like the better option to me.

I’m thinking whether sending back the fully-qualified types might blow up the response and if we should add an option to the request to control whether fully-qualified types are sent. I don’t have strong opinions either way but @rintaro might.

I think adding this as an option would have been the better in the first place, so I'm open to updating it. But let's first see if @rintaro has any comments on this.

[rintaro]

While it's true that this will more than double the size of the result, since duplicated type names are shared in the string buffer, I'm not too worried about the size of the response.

That being said, having a option would be great 👍

[skrtks]

I've updated the implementation so that it doesn't return the fully qualified type as an extra key anymore. Instead, the request option fully_qualified can be used to get the fully qualified type.

[ahoppen]

Looks good to me. One suggestion to merge two test files.

[ahoppen]

This is just a copy of basic.swift, right? You could also just add another RUN: line to it with %FileCheck %s --check-prefix CHECK-FULLY-QUALIFIED

[skrtks]

It is indeed, I was looking for a way to do this, but missed the custom prefix. Thanks for pointing it out!

[ahoppen]

@swift-ci Please smoke test