SeeAlso documentation callouts (Swift) do not display in Xcode quick help

Number:rdar://36925268 Date Originated:2018-01-26
Status:Open Resolved:
Product:Developer Tools Product Version:Xcode 9.2 (9C40b), Xcode 9.3 beta (9Q98q)
Classification:Bug Reproducible:Always
When a SeeAlso documentation callout is added to the documentation comment for a symbol, it does not display in the Quick Help dialog for that symbol.

Steps to Reproduce:
- Open Xcode
- Create a new project (of any type, but for example, a macOS Command Line Tool)
- In a Swift file, declare a symbol, such as `struct Foo { }`
- Build the project, and verify that it builds successfully
- Add a documentation comment before the symbol. This documentation comment can be either a block comment, surrounded by /** and */, or a single-line comment, beginning with ///.
- Add a SeeAlso callout within the documentation comment, in any of the following forms:
    - SeeAlso: Bar
    + SeeAlso: Bar
    * SeeAlso: Bar
    - seealso: Bar
    + seealso: Bar
    * seealso: Bar (Note: this form, when inserted inside a block comment, is parsed as "seealso: Bar" and displayed as plain text, because the leading * is stripped out to allow for a leading * on each line to form a vertical bar in the documentation comment)
- Build the project again, and verify that it builds successfully
- Option-click on the symbol `Foo`, Command-Control-click on the symbol and click Quick Help, or place the cursor on the symbol and open the Quick Help inspector
- Observe the result

Expected Results:
The SeeAlso callout and its contents are rendered in the quick help window, with a bold heading reading "See Also", as described in the Markup Formatting Reference here:

Actual Results:
The SeeAlso callout is not rendered in any form (either its contents or the heading, in plain or formatted text). See the attached file "actualresults.png".

- Xcode 9.2 (9C40b), macOS High Sierra 10.13.3 (17D47)
- Xcode 9.3 beta (9Q98q), macOS High Sierra 10.13.3 (17D47)


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