Upgrade Core to 4e9d280a8a452885c7cd2bc488799a4f6410f4d8

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>

Author: jviotti

DEPENDENCIES

@@ -1,2 +1,2 @@
 vendorpull https://github.com/sourcemeta/vendorpull 1dcbac42809cf87cb5b045106b863e17ad84ba02
-core https://github.com/sourcemeta/core 991a4c86b6b22b73aedabe5734cba7108a781953
+core https://github.com/sourcemeta/core 4e9d280a8a452885c7cd2bc488799a4f6410f4d8

src/ir/ir.cc

@@ -46,7 +46,10 @@ auto compile(const sourcemeta::core::JSON &input,
   // (4) Convert every subschema into a code generation object
   // --------------------------------------------------------------------------
 
-  std::unordered_set<sourcemeta::core::WeakPointer> visited;
+  std::unordered_set<sourcemeta::core::WeakPointer,
+                     sourcemeta::core::WeakPointer::Hasher,
+                     sourcemeta::core::WeakPointer::Comparator>
+      visited;
   IRResult result;
   for (const auto &[key, location] : frame.locations()) {
     if (location.type !=