diff --git a/lib/graphql/schema/member/has_fields.rb b/lib/graphql/schema/member/has_fields.rb
index 0f38f089cc..4f03bc1968 100644
--- a/lib/graphql/schema/member/has_fields.rb
+++ b/lib/graphql/schema/member/has_fields.rb
@@ -127,7 +127,10 @@ def add_super_method(field_key, method_name)
 ERR
           end
           default_resolve_module.module_eval <<-RUBY, __FILE__, __LINE__ + 1
-            def #{method_name}(**args)
+            # method_name can be a hash_key (see lib/graphql/schema/field.rb)
+            # so we need to make a raw define_method :sym call to avoid crashing
+            # on hash keys like :'some key with/weird-chars'
+            define_method #{method_name.inspect} do |**args|
               field_inst = self.class.fields[#{field_key}] || raise(%|Failed to find field #{field_key} for \#{self.class} among \#{self.class.fields.keys}|)
               field_inst.resolve_field_method(self, args, context)
             end
diff --git a/spec/graphql/schema/member/has_fields_spec.rb b/spec/graphql/schema/member/has_fields_spec.rb
index a67906efc7..0165e6c8fd 100644
--- a/spec/graphql/schema/member/has_fields_spec.rb
+++ b/spec/graphql/schema/member/has_fields_spec.rb
@@ -75,6 +75,7 @@ def int
       field :string3, SubSubObjectWithStringField, null: false, method: :object
       field :float1, ObjectWithFloatField, null: false, method: :object
       field :float2, ObjectWithSubFloatField, null: false, method: :object
+      field :hash_key1, String, null: false, hash_key: :'foo bar/fizz-buzz'
     end
 
     class Schema < GraphQL::Schema