Fix match AccessType

[trdthg]

-                            Read()          => false,
+                            Read(_)         => false,

I don't know why the previous one could compile, it should be wrong, but after replacing ext_access_type with newtype, the compiler detected the error correctly.

union AccessType ('a : Type) = {
  Read      : 'a,
  Write     : 'a,
  ReadWrite : ('a, 'a),
  Execute   : unit
}

[Timmmm]

Ah interesting. So the reason this wasn't an issue before is that Sail treats unit union variants specially:

union Foo = {
  A : unit,
  B : unit,
  C : unit,
  D : int,
}

function test(f : Foo) -> int =
  match f {
    // These are all ok for unit
    A(()) => 0,
    B() => 1,
    C(_) => 2,
    // But int requires _.
    D(_) => 3,
  }

So Read() would only work if ext_access_type is unit. Extended versions of the model are allowed to change it, and then Read() wouldn't work... except that the only extended version of the model that really exists and uses this is CHERI and that also replaces the entire riscv_vmem_pte.sail file too.

So yeah, we should change the Read() to Read(_) anyway, but I don't see any reason to use newtype?

[github-actions]

Test Results

396 tests  ±0   396 ✅ ±0   0s ⏱️ ±0s
  4 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit a9b6c0c. ± Comparison against base commit 70edcb0.

♻️ This comment has been updated with latest results.

[trdthg]

done