[SR-14552] SwiftSyntax crashes when parsing a malformed function type

[allevato]

Previous ID	SR-14552
Radar	rdar://problem/77391988
Original Reporter	@allevato
Type	Bug
Status	Resolved
Resolution	Done

Attachment: Download

Additional Detail from JIRA

Votes	0
Component/s	SwiftSyntax
Labels	Bug
Assignee	@ahoppen
Priority	Medium

md5: 103052cad603311e83a1a277c4a8f594

Issue Description:

This is a repro of a case that recently started failing in one of swift-format's tests against the main branch (I'm using the 2021-04-26 development snapshot as my current environment).

When parsing the following source code:

{{ let x: (A -> B)}}

(Note that "A" should have its own parentheses surrounding it for this to be valid.)

The parser crashes with the following message:

Assertion failed: (isValid() && "length does not make sense for an invalid range"), function getByteLength, file /Users/buildnode/jenkins/workspace/oss-swift-package-macos/swift/include/swift/Basic/SourceLoc.h, line 218.

I would expect this to fail in some other, non-crashing fashion, such as expressing the syntax using Unknown* nodes.

To reproduce:

1. Download the attached project.

2. Use a development toolchain that is syntax-compatible with swift-syntax's main branch (at the time I'm writing this, 2021-04-26 worked).

3. Run swift run TriviaCrash.

[ahoppen]

@swift-ci create

[ahoppen]

Thanks for reporting this @allevato. I’ve put up a

• PR for main: apple/swift#37241

• PR for 5.5: apple/swift#37242