Array expression fails to compile due to internal error

[sangkilc]

Some array expressions fail to compile with the following error message: Error in pass3 for type Program, error: ldelem. This is easily reproduced with the latest F# 9 (.NET 9) on Windows.

Repro steps

let arr1 = [| 0; 1; 2; 3 |]
let arr2 = [| 0UL; 1UL; 2UL; 3UL |]
let wrap x = [| x |]
let good = [| for a in arr1 do wrap a |]
let bad = [| for a in arr2 do wrap a |] // this is causing the prob

When copy-paste the above code to dotnet fsi, the last line produces the error:

> let bad = [| for a in arr2 do wrap a |];;


error FS0192: internal error: Error in pass3 for type <StartupCode$FSI_0003>.$FSI_0003, error: ldelem

Expected behavior

It should compile.

Actual behavior

Internal error

Known workarounds

By using F# 8 (.NET 8) the same code compiles:

> let arr1 = [| 0; 1; 2; 3 |]
- let arr2 = [| 0UL; 1UL; 2UL; 3UL |]
- let wrap x = [| x |]
- let good = [| for a in arr1 do wrap a |]
- let bad = [| for a in arr2 do wrap a |];;
val arr1: int array = [|0; 1; 2; 3|]
val arr2: uint64 array = [|0UL; 1UL; 2UL; 3UL|]
val wrap: x: 'a -> 'a array
val good: int array array = [|[|0|]; [|1|]; [|2|]; [|3|]|]
val bad: uint64 array array = [|[|0UL|]; [|1UL|]; [|2UL|]; [|3UL|]|]

Related information

I'm using the latest .NET 9 (VS 17.12.3) on Windows.

.NET SDK:
 Version:           9.0.101
 Commit:            eedb237549
 Workload version:  9.0.100-manifests.4a280210
 MSBuild version:   17.12.12+1cce77968

[brianrourkeboll]

I think this is the same as #18066, fixed in #18081. It should (hopefully) be in 9.0.200.