Fixed #3805: incorrect type for generic instance whose generic type has subclasses

Ary Borenszweig · Ary Borenszweig · commit a62dff31476f · 2016-12-30T17:06:34.000-03:00
diff --git a/spec/compiler/semantic/instance_var_spec.cr b/spec/compiler/semantic/instance_var_spec.cr
@@ -4578,4 +4578,27 @@ describe "Semantic: instance var" do
       Foo.new.x
       )) { int32 }
   end
+
+  it "types generic instance as virtual type if generic type has subclasses (#3805)" do
+    assert_type(%(
+      class Foo(T)
+      end
+
+      class Bar(T) < Foo(T)
+      end
+
+      class Qux
+        def initialize
+          @ptr = Pointer(Foo(Int32)).malloc(1_u64)
+        end
+
+        def ptr=(ptr)
+          @ptr = ptr
+        end
+      end
+
+      Bar(Int32).new
+      Qux.new
+      )) { types["Qux"] }
+  end
 end
diff --git a/src/compiler/crystal/types.cr b/src/compiler/crystal/types.cr
@@ -1683,9 +1683,9 @@ module Crystal
     end
 
     def virtual_type
-      if leaf? && !abstract?
+      if generic_type.leaf? && !abstract?
         self
-      elsif struct? && abstract? && !leaf?
+      elsif struct? && abstract? && !generic_type.leaf?
         virtual_type!
       elsif struct?
         self
