FSI hangs if illformed string is inserted

[realvictorprm]

FSI hangs if an illformed string is inserted.

Repro steps

1. Open FSI in VS or via command prompt
2. Type in let test = """\"""";;
3. See that FSI hangs

Expected behavior

FSI doesn't hang up and show some error.

Actual behavior

FSI hangs up without error.

Known workarounds

Don't type in illformed strings.

Related information

Microsoft Visual Studio Community 2017
Version 15.8.0
VisualStudio.15.Release/15.8.0+28010.0
Microsoft .NET Framework
Version 4.7.03056

Installierte Version: Community
Visual F# Tools 10.2 für F# 4.5 15.8.0.0. Commit Hash: c55dd2c.
Microsoft Visual F# Tools 10.2 für F# 4.5

[smoothdeveloper]

Note that it doesn't hang, it is waiting for more input and the string to be completed.

I'm not sure there is a more graceful way to handle this, do you know any REPL that handle this better that we could draw inspiration from?

[abelbraaksma]

Good to see others are stunned by this too. This is a duplicate of #4802.

[abelbraaksma]

Perhaps an improvement is to show a message hint on enter, since that usually executes what's already there: "Quoted string detected that wasn't properly closed, expected a quote character."

Or recognize ';;' even when it's inside a non-closed string, as the end of the statement, perhaps provided that it's the last two characters. It's unlikely the programmer meant anything else.

[cartermp]

Heh, this is some bad issue management on our part. Closing as a duplicate of #830

[realvictorprm]

thanks

[abelbraaksma]

Oh, there was even an older one! :D