Transparent Compiler: Different diagnostics results

[safesparrow]

Using the Transparent Compiler in FCS produces different diagnostics for the Fantomas solution.

Repro steps

Run the below script that checks out and runs the fsharp_scripts tool:

git clone https://github.com/safesparrow/fsharp_scripts
cd fsharp_scripts
git checkout 1af31008beb27a1ab29a7e881b1aa5c1627cfc62
cd Scripts.Sample
dotnet run

The program involves the following steps:

1. Clone https://github.com/fsprojects/fantomas
2. Restore + project cracking
3. Use FSharpChecker with TransparentCompiler=true to request a check of all the projects in the solution in parallel and dump diagnostics
4. Use FSharpChecker with TransparentCompiler=false to request a check of all the projects in the solution in parallel and dump diagnostics

Expected behavior

Diagnostics are identical in both runs.

Actual behavior

First check, using TransparentCompiler=true, produces the following diagnostic:

[12:22:52 INF]  : Diagnostic | Fantomas.FCS.fsproj | ..\..\.deps\e2496896c128ccfde33c92f45bbe0d2aa738873a\src\Compiler\lex.fsl | This expression was expected to have type    ''a -> string'    but here has type    'string'

Second check, using TransparentCompiler=false, produces a different diagnostic:

[12:23:09 INF]  : Diagnostic | Fantomas.Tests.fsproj | C:\projekty\fsharp\test_f\fsharp_scripts\.cache\fsprojects__fantomas\de8ac507\_\src\Fantomas.Tests\IgnoreFileTests.fs | The value 'current'' is not accessible from this code location

Known workarounds

Do not use TransparentCompiler

Related information

Provide any related information (optional):

• FCS version 43.8.300-preview.24115.2, published on 2024-02-16 (latest available on NuGet)
• Windows 11
• Samples project run using SDK 8.0.101
• Editing Tools (e.g. Visual Studio Version, Visual Studio)