[SR-12998] Raw Value of literal String #file breaks enum with String Protocol

[swift-ci]

Previous ID	SR-12998
Radar	None
Original Reporter	0-1 (JIRA User)
Type	Bug
Status	Resolved
Resolution	Done

Additional Detail from JIRA

Votes	0
Component/s	Compiler
Labels	Bug, CompilerCrash, TypeChecker
Assignee	@theblixguy
Priority	Medium

md5: da1a27a777b6be474b5c910416171f6d

relates to:

• SR-13022 Support magic literals as enum case raw value

Issue Description:

Bug with #file

enum Foo: String {

{{ case bar = #file}}

{{}}}

This causes an internal error: Segmentation Fault: 11

Is #file considered a literal String?

"(5)" is not a literal. But Apple's Swift 5.2 Guide describes #file, #line, #function, #colorLiteral, etc. all as literals.

___

Bug with nil

enum I:Int?{

{{ case a = nil}}

{{}}}

[theblixguy]

The problem is that the value associated with the magic literals are not available in the type checker (they're emitted in SILGen), which means we can't do a uniqueness check. I suppose we could make it work by only allowing only one magic literal of each kind to be associated with an enum case (i.e. you can't have two cases of #line) but I am not sure if that's a better rule than not allowing magic literals in the first place.

Regardless, the compiler shouldn't be crashing here, which is a bug.

EDIT: Upon thinking a bit more, I think it's possible to support these literals by moving some of the code from SILGen into AST/Sema. I'll give it a try soon.

[swift-ci]

Comment by Jonathan Pappas (JIRA)

@theblixguy Thank you,

I also found that using ExpressibleByNilLiteral and setting one of the raw values to nil also causes the same issue.

[theblixguy]

Thanks. I don’t think nil can be supported as it’s not a unique literal. I think the only ones that can potentially be supported is #file, #function, #line and #column.

[theblixguy]

The crash is now fixed by #32364. I'll create a new SR to track adding support for #file, #filePath, #function, #line and #column.