[Parse] Fix minor bug in #sourceLocation on lex error

[johnno1962]

There seems to be a minor bug in the implementation of #sourceLocation when the directive is succeeded by token that gives an error during lexing. The error will be reported with the wrong location. This is because lexing of the next token occurs immediately on consuming the last token of the directive which is before the virtual file is set up to have the location take effect.

Resolved by moving consumption of directives last token to the end of the function.

Resolves SR-8772.

[jrose-apple]

Thanks! I'd still like @rintaro or someone more parsery to confirm the actual fix, but I'm glad it's testable.

[rintaro]

Thanks for working on this! This is definitely an improvement.
Unfortunately, I think, this is not perfect. Could you try this?

#sourceLocation(file: "test.swift", line: 1000)
0xG

When the parser is at ), the Lexer have already read 0xG for peekToken().
Do you want to tackle on this issue? Similar one is here: https://bugs.swift.org/browse/SR-3415
If you prefer not to do it on this PR, it's OK, I'll merge this.

[rintaro]

@swift-ci Please smoke test

[johnno1962]

I think I’ll leave the bug you mention for another day but I was looking at making the “file:" optional in #sourceLocation. Do you think that would be worthwhile? That also can be a exercise for another day. Merge away...

[rintaro]

@swift-ci Please smoke test

[jrose-apple]

@swift-ci Please smoke test

[johnno1962]

@jrose-apple I think I may have pushed a commit after your Please smoke test

[jrose-apple]

@swift-ci Please smoke test

[rintaro]

Thank you!

[johnno1962]

Thanks all, we got there there in the end. Any thoughts on the rather eccentric #19347?