Compiler: devirtualize inherited types

asterite · jhass · commit 252436226d0a · 2018-01-04T17:31:20.000+01:00
diff --git a/spec/compiler/semantic/class_spec.cr b/spec/compiler/semantic/class_spec.cr
@@ -1061,4 +1061,18 @@ describe "Semantic: class" do
       ),
       "undefined method 'bar' for Foo:Class"
   end
+
+  it "inherits self twice (#5495)" do
+    assert_type(%(
+      class Foo
+        class Bar < self
+        end
+
+        class Baz < self
+        end
+      end
+
+      { {{ Foo::Bar.superclass }}, {{ Foo::Baz.superclass }} }
+    )) { tuple_of [types["Foo"].metaclass, types["Foo"].metaclass] }
+  end
 end
diff --git a/src/compiler/crystal/semantic/top_level_visitor.cr b/src/compiler/crystal/semantic/top_level_visitor.cr
@@ -137,7 +137,7 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
       # type parameters because they will always be unbound.
       superclass = lookup_type(node_superclass,
         free_vars: free_vars,
-        find_root_generic_type_parameters: false)
+        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})"
