Go: Unable to match specific members within a struct initialization when using pattern-inside

[enncoded]

Describe the bug
I'm having trouble matching specific MemberName: Value pairs when using a pattern-inside along with a pattern to match specific members of a struct.

To Reproduce
https://semgrep.dev/s/68B1

While playing around with it, I noticed that you can match the MemberNames, such as ServerName or InsecureSkipVerify, but not the Values or MemberName: Value pairs.

Expected behavior
The InsecureSkipVerify: true should match

What is the priority of the bug to you?

• P0: blocking your adoption of Semgrep or workflow
• P1: important to fix or quite annoying
• P2: regular bug that should get fixed

Use case
Allow me to write more detailed Go rules

[r2c-demo]

This issue is synced in Linear at https://linear.app/r2c/issue/PA-1453/go-unable-to-match-specific-members-within-a-struct-initialization. Note: this link is for r2c use only and is not accessible publicly.

[kopecs]

Something like https://semgrep.dev/s/j44N should work---we probably don't try and parse a pattern as being a field right now, although we could change that if using a metavariable-pattern & focus-metavariable is an issue.

[enncoded]

Oh thanks! I didn't think of this. I'll see how far I can go with this for now, but I definitely do think that this is important to fix, as narrowing scope as much as possible using pattern-inside and using pattern to match internal stuff is a very common rule pattern.

[aryx]

We actually do parse the pattern as a field (see -dump_pattern with PartialSingleField). The problem is that the Composite Literal (the tls.Config {xxx}) is internally parsed as a function call with keyword arguments instead of a Record,
and so the PartialSingleField pattern does not match an ArgKwd.
I'll try to fix it by generating a Record. Not sure why we were not doing that in the first place.

[aryx]

Hmm I think it's because the composite literal can also be written with the "fields" unnamed as long as they are in the same order.