Compiler: fixed bug related to nested generic classes. Fixes #3297

crystal-lang · Sep 13, 2016 · 83678c4 · 83678c4
1 parent e4dd5b4
commit 83678c4
Showing 2 changed files with 22 additions and 2 deletions.
diff --git a/spec/compiler/semantic/generic_class_spec.cr b/spec/compiler/semantic/generic_class_spec.cr
@@ -930,4 +930,24 @@ describe "Semantic: generic class" do
       Connection(Client).new.packets
       )) { generic_class "Array", generic_class("OutgoingPacket", types["Client"]).virtual_type! }
   end
+
+  it "nests generics with the same type var (#3297)" do
+    assert_type(%(
+      class Foo(A)
+        @a : A
+
+        def initialize(@a : A)
+        end
+
+        def a
+          @a
+        end
+
+        class Bar(A) < Foo(A)
+        end
+      end
+
+      Foo::Bar.new(:a).a
+      ), inject_primitives: false) { symbol }
+  end
 end
diff --git a/src/compiler/crystal/semantic/type_lookup.cr b/src/compiler/crystal/semantic/type_lookup.cr
@@ -67,9 +67,9 @@ class Crystal::Type
       # for example Hash(K, V), we want to find K and V as type parameters
       # of that type.
       if root.is_a?(GenericType)
-        free_vars = {} of String => TypeVar
+        free_vars ||= {} of String => TypeVar
         root.type_vars.each do |type_var|
-          free_vars[type_var] = TypeParameter.new(program, root, type_var)
+          free_vars[type_var] ||= TypeParameter.new(program, root, type_var)
         end
         @free_vars = free_vars
       end