types: fix hash values of Vararg (#50932)

Fixes #50455

Author: vtjnash

src/jltypes.c

@@ -1597,19 +1597,20 @@ static unsigned typekey_hash(jl_typename_t *tn, jl_value_t **key, size_t n, int
     int failed = nofail;
     for (j = 0; j < n; j++) {
         jl_value_t *p = key[j];
+        size_t repeats = 1;
         if (jl_is_vararg(p)) {
             jl_vararg_t *vm = (jl_vararg_t*)p;
-            if (!nofail && vm->N)
-                return 0;
-            // 0x064eeaab is just a randomly chosen constant
-            hash = bitmix(vm->N ? type_hash(vm->N, &failed) : 0x064eeaab, hash);
-            if (failed && !nofail)
-                return 0;
+            if (vm->N && jl_is_long(vm->N))
+                repeats = jl_unbox_long(vm->N);
+            else
+                hash = bitmix(0x064eeaab, hash); // 0x064eeaab is just a randomly chosen constant
             p = vm->T ? vm->T : (jl_value_t*)jl_any_type;
         }
-        hash = bitmix(type_hash(p, &failed), hash);
+        unsigned hashp = type_hash(p, &failed);
         if (failed && !nofail)
             return 0;
+        while (repeats--)
+            hash = bitmix(hashp, hash);
     }
     hash = bitmix(~tn->hash, hash);
     return hash ? hash : 1;

test/tuple.jl

@@ -796,3 +796,8 @@ namedtup = (;a=1, b=2, c=3)
 @test_throws ErrorException("Tuple field type cannot be Union{}") Tuple{Vararg{Union{},1}}
 @test Tuple{} <: Tuple{Vararg{Union{},N}} where N
 @test !(Tuple{} >: Tuple{Vararg{Union{},N}} where N)
+
+@test Val{Tuple{T,T,T} where T} === Val{Tuple{Vararg{T,3}} where T}
+@test Val{Tuple{Vararg{T,4}} where T} === Val{Tuple{T,T,T,T} where T}
+@test Val{Tuple{Int64, Vararg{Int32,N}} where N} === Val{Tuple{Int64, Vararg{Int32}}}
+@test Val{Tuple{Int32, Vararg{Int64}}} === Val{Tuple{Int32, Vararg{Int64,N}} where N}