diff --git a/src/spectator/expectations/expectation_partial.cr b/src/spectator/expectations/expectation_partial.cr
index e848eaf..31606b2 100644
--- a/src/spectator/expectations/expectation_partial.cr
+++ b/src/spectator/expectations/expectation_partial.cr
@@ -24,10 +24,10 @@ module Spectator::Expectations
       report(match_data)
     end
 
-    def to(stub : Mocks::GenericMethodStub(RT, T, NT)) : Nil forall RT, T, NT
+    def to(stub : Mocks::MethodStub) : Nil
       value = TestValue.new(stub.name, stub.to_s)
-      matcher = if stub.arguments?
-        Matchers::ReceiveArgumentsMatcher.new(value, stub.arguments)
+      matcher = if (arguments = stub.arguments?)
+        Matchers::ReceiveArgumentsMatcher.new(value, arguments)
       else
         Matchers::ReceiveMatcher.new(value)
       end
@@ -42,7 +42,13 @@ module Spectator::Expectations
     end
 
     def to_not(stub : Mocks::MethodStub) : Nil
-      raise NotImplementedError.new("`expect(double).to_not receive(message)` syntax not implemented yet")
+      value = TestValue.new(stub.name, stub.to_s)
+      matcher = if (arguments = stub.arguments?)
+        Matchers::ReceiveArgumentsMatcher.new(value, arguments)
+      else
+        Matchers::ReceiveMatcher.new(value)
+      end
+      to_never(matcher)
     end
 
     # ditto
diff --git a/src/spectator/matchers/receive_arguments_matcher.cr b/src/spectator/matchers/receive_arguments_matcher.cr
index bc729db..e4053cc 100644
--- a/src/spectator/matchers/receive_arguments_matcher.cr
+++ b/src/spectator/matchers/receive_arguments_matcher.cr
@@ -2,10 +2,10 @@ require "../mocks"
 require "./standard_matcher"
 
 module Spectator::Matchers
-  struct ReceiveArgumentsMatcher(T, NT) < StandardMatcher
+  struct ReceiveArgumentsMatcher < StandardMatcher
     alias Range = ::Range(Int32, Int32) | ::Range(Nil, Int32) | ::Range(Int32, Nil)
 
-    def initialize(@expected : TestExpression(Symbol), @args : Mocks::GenericArguments(T, NT), @range : Range? = nil)
+    def initialize(@expected : TestExpression(Symbol), @args : Mocks::Arguments, @range : Range? = nil)
     end
 
     def description : String
diff --git a/src/spectator/mocks/generic_method_stub.cr b/src/spectator/mocks/generic_method_stub.cr
index 373de46..c0ee38f 100644
--- a/src/spectator/mocks/generic_method_stub.cr
+++ b/src/spectator/mocks/generic_method_stub.cr
@@ -4,10 +4,10 @@ require "./method_call"
 require "./method_stub"
 
 module Spectator::Mocks
-  abstract class GenericMethodStub(ReturnType, T, NT) < MethodStub
-    getter! arguments : GenericArguments(T, NT)
+  abstract class GenericMethodStub(ReturnType) < MethodStub
+    getter! arguments : Arguments
 
-    def initialize(name, source, @args : GenericArguments(T, NT) = nil)
+    def initialize(name, source, @args : Arguments? = nil)
       super(name, source)
     end
 
diff --git a/src/spectator/mocks/nil_method_stub.cr b/src/spectator/mocks/nil_method_stub.cr
index 0bfe4d7..64e10bb 100644
--- a/src/spectator/mocks/nil_method_stub.cr
+++ b/src/spectator/mocks/nil_method_stub.cr
@@ -3,7 +3,7 @@ require "./generic_method_stub"
 require "./value_method_stub"
 
 module Spectator::Mocks
-  class NilMethodStub < GenericMethodStub(Nil, Tuple, NamedTuple)
+  class NilMethodStub < GenericMethodStub(Nil)
     def call(_args : GenericArguments(T, NT), _rt : RT.class) forall T, NT, RT
       nil
     end
diff --git a/src/spectator/mocks/proc_method_stub.cr b/src/spectator/mocks/proc_method_stub.cr
index f4a9603..b0d921f 100644
--- a/src/spectator/mocks/proc_method_stub.cr
+++ b/src/spectator/mocks/proc_method_stub.cr
@@ -2,7 +2,7 @@ require "./arguments"
 require "./generic_method_stub"
 
 module Spectator::Mocks
-  class ProcMethodStub(ReturnType, T, NT) < GenericMethodStub(ReturnType, T, NT)
+  class ProcMethodStub(ReturnType) < GenericMethodStub(ReturnType)
     def initialize(name, source, @proc : -> ReturnType, args = nil)
       super(name, source, args)
     end
diff --git a/src/spectator/mocks/value_method_stub.cr b/src/spectator/mocks/value_method_stub.cr
index f55ea49..6cdec7b 100644
--- a/src/spectator/mocks/value_method_stub.cr
+++ b/src/spectator/mocks/value_method_stub.cr
@@ -2,7 +2,7 @@ require "./generic_arguments"
 require "./generic_method_stub"
 
 module Spectator::Mocks
-  class ValueMethodStub(ReturnType, T, NT) < GenericMethodStub(ReturnType, T, NT)
+  class ValueMethodStub(ReturnType) < GenericMethodStub(ReturnType)
     def initialize(name, source, @value : ReturnType, args = nil)
       super(name, source, args)
     end