[FSharp.Editor] tooltips shows unnamed types when there is an error in a file / project which has type provider

Edit: with VS 17.8.

I'm editing [FSharp.Data.SqlClient\tests\SqlClient.Tests\SqlEnumTests.fs](https://github.com/fsprojects/FSharp.Data.SqlClient/blob/master/tests/SqlClient.Tests/SqlEnumTests.fs) by breaking a bit of code unrelated to the type provider (splitting an `Assert.Equal` into `Assert.Eq ual` by putting a space), and I'm kind of seeing unnamed types and noise in the tooltip to read about the error introduced in the code.