Remove `HashType::Unknown`

Instead, `Hash` uses `std::optional<HashType>`. In the future, we may
also make `Hash` itself require a known hash type, encoraging people to
use `std::optional<Hash>` instead.

1 files changed, 1 insertions, 3 deletions

diff --git a/src/nix/hash.cc b/src/nix/hash.cc
index 3362ffd0d..4980cd198 100644
--- a/src/nix/hash.cc
+++ b/src/nix/hash.cc
@@ -79,7 +79,7 @@ static RegisterCommand r2("hash-path", [](){ return make_ref<CmdHash>(FileIngest
 struct CmdToBase : Command
 {
     Base base;
-    HashType ht = HashType::Unknown;
+    HashType ht;
     std::vector<std::string> args;
 
     CmdToBase(Base base) : base(base)
@@ -132,8 +132,6 @@ static int compatNixHash(int argc, char * * argv)
         else if (*arg == "--type") {
             string s = getArg(*arg, arg, end);
             ht = parseHashType(s);
-            if (ht == HashType::Unknown)
-                throw UsageError(format("unknown hash type '%1%'") % s);
         }
         else if (*arg == "--to-base16") op = opTo16;
         else if (*arg == "--to-base32") op = opTo32;