Fix test for Windows paths and add test for errors in loaded files

Co-authored-by: abonie <20281641+abonie@users.noreply.github.com>

Author: Copilot

src/Compiler/Interactive/fsi.fs

@@ -2500,7 +2500,18 @@ type internal FsiDynamicCompiler
         let isIncrementalFragment = true
 
         let istate, tcEnvAtEndOfLastInput, declaredImpls =
-            ProcessInputs(ctok, diagnosticsLogger, istate, [ input ], showTypes, isIncrementalFragment, isInteractiveItExpr, prefix, m, false)
+            ProcessInputs(
+                ctok,
+                diagnosticsLogger,
+                istate,
+                [ input ],
+                showTypes,
+                isIncrementalFragment,
+                isInteractiveItExpr,
+                prefix,
+                m,
+                false
+            )
 
         let tcState = istate.tcState
 

tests/FSharp.Compiler.ComponentTests/Scripting/TypeCheckOnlyTests.fs

@@ -1,5 +1,6 @@
 module FSharp.Compiler.ComponentTests.Scripting.TypeCheckOnlyTests
 
+open System
 open System.IO
 open Xunit
 open FSharp.Test
@@ -51,19 +52,50 @@ let x = 21+21
 let ``typecheck-only flag catches type errors in scripts with #load``() =
     let tempDir = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName())
     Directory.CreateDirectory(tempDir) |> ignore
+    let originalDir = Environment.CurrentDirectory
 
     try
+        Environment.CurrentDirectory <- tempDir
         let domainPath = Path.Combine(tempDir, "Domain.fsx")
         let mainPath = Path.Combine(tempDir, "A.fsx")
 
         File.WriteAllText(domainPath, "type T = { Field: string }\nprintfn \"D\"")
-        File.WriteAllText(mainPath, sprintf "#load \"%s\"\nopen Domain\nlet y = { Field = 1 }\nprintfn \"A\"" domainPath)
+        File.WriteAllText(mainPath, "#load \"Domain.fsx\"\nopen Domain\nlet y = { Field = 1 }\nprintfn \"A\"")
 
         FsxFromPath mainPath
         |> withOptions ["--typecheck-only"]
         |> runFsi
         |> shouldFail
         |> withStdErrContains "This expression was expected to have type"
     finally
-        if Directory.Exists(tempDir) then
-            Directory.Delete(tempDir, true)
+        try
+            Environment.CurrentDirectory <- originalDir
+            if Directory.Exists(tempDir) then
+                Directory.Delete(tempDir, true)
+        with _ -> ()
+
+[<Fact>]
+let ``typecheck-only flag catches type errors in loaded file``() =
+    let tempDir = Path.Combine(Path.GetTempPath(), Path.GetRandomFileName())
+    Directory.CreateDirectory(tempDir) |> ignore
+    let originalDir = Environment.CurrentDirectory
+    
+    try
+        Environment.CurrentDirectory <- tempDir
+        let domainPath = Path.Combine(tempDir, "Domain.fsx")
+        let mainPath = Path.Combine(tempDir, "A.fsx")
+        
+        File.WriteAllText(domainPath, "type T = { Field: string }\nlet x: int = \"error\"\nprintfn \"D\"")
+        File.WriteAllText(mainPath, "#load \"Domain.fsx\"\nopen Domain\nlet y = { Field = \"ok\" }\nprintfn \"A\"")
+        
+        FsxFromPath mainPath
+        |> withOptions ["--typecheck-only"]
+        |> runFsi
+        |> shouldFail
+        |> withStdErrContains "This expression was expected to have type"
+    finally
+        try
+            Environment.CurrentDirectory <- originalDir
+            if Directory.Exists(tempDir) then
+                Directory.Delete(tempDir, true)
+        with _ -> ()