diff --git a/spec/compiler/semantic/generic_class_spec.cr b/spec/compiler/semantic/generic_class_spec.cr
index 6e8f48d486f2..a8759d096d4b 100644
--- a/spec/compiler/semantic/generic_class_spec.cr
+++ b/spec/compiler/semantic/generic_class_spec.cr
@@ -324,7 +324,7 @@ describe "Semantic: generic class" do
       class Bar < Foo
       end
       ),
-      "wrong number of type vars for Foo(T) (given 0, expected 1)"
+      "generic type arguments must be specified when inheriting Foo(T)"
   end
 
   %w(Object Value Reference Number Int Float Struct Class Proc Tuple Enum StaticArray Pointer).each do |type|
diff --git a/spec/compiler/semantic/module_spec.cr b/spec/compiler/semantic/module_spec.cr
index b857fd3d5e7f..8ea5217f5ad7 100644
--- a/spec/compiler/semantic/module_spec.cr
+++ b/spec/compiler/semantic/module_spec.cr
@@ -101,7 +101,7 @@ describe "Semantic: module" do
       "wrong number of type vars for Foo(T, U) (given 1, expected 2)"
   end
 
-  it "includes generic module but wrong number of arguments 2" do
+  it "errors if including generic module and not specifying type vars" do
     assert_error "
       module Foo(T)
       end
@@ -110,7 +110,7 @@ describe "Semantic: module" do
         include Foo
       end
       ",
-      "wrong number of type vars for Foo(T) (given 0, expected 1)"
+      "generic type arguments must be specified when including Foo(T)"
   end
 
   it "includes generic module explicitly" do
diff --git a/src/compiler/crystal/semantic/top_level_visitor.cr b/src/compiler/crystal/semantic/top_level_visitor.cr
index d3052dfd15b2..a5b5bac70723 100644
--- a/src/compiler/crystal/semantic/top_level_visitor.cr
+++ b/src/compiler/crystal/semantic/top_level_visitor.cr
@@ -116,7 +116,7 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
         find_root_generic_type_parameters: false).devirtualize
       case superclass
       when GenericClassType
-        node_superclass.raise "wrong number of type vars for #{superclass} (given 0, expected #{superclass.type_vars.size})"
+        node_superclass.raise "generic type arguments must be specified when inheriting #{superclass}"
       when NonGenericClassType, GenericClassInstanceType
         if superclass == @program.enum
           node_superclass.raise "can't inherit Enum. Use the enum keyword to define enums"
@@ -980,7 +980,7 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
     type = lookup_type(node_name)
     case type
     when GenericModuleType
-      node.raise "wrong number of type vars for #{type} (given 0, expected #{type.type_vars.size})"
+      node.raise "generic type arguments must be specified when including #{type}"
     when .module?
       # OK
     else