Fixed #3423: superclass mismatch in overloading of a generic open class

crystal-lang · Oct 15, 2016 · 7025618 · 7025618
1 parent 6aa58a3
commit 7025618
Showing 5 changed files with 25 additions and 4 deletions.
diff --git a/spec/compiler/semantic/generic_class_spec.cr b/spec/compiler/semantic/generic_class_spec.cr
@@ -966,4 +966,19 @@ describe "Semantic: generic class" do
       foo(Gen(String).new.as(Gen(String)))
       )) { int32 }
   end
+
+  it "subclasses twice with same generic class (#3423)" do
+    assert_type(%(
+      class Foo(T)
+      end
+
+      class Bar(T) < Foo(T)
+      end
+
+      class Bar(T) < Foo(T)
+      end
+
+      Bar(Int32).new
+      )) { generic_class "Bar", int32 }
+  end
 end
diff --git a/src/compiler/crystal/program.cr b/src/compiler/crystal/program.cr
@@ -163,7 +163,7 @@ module Crystal
 
       types["StaticArray"] = static_array = @static_array = StaticArrayType.new self, self, "StaticArray", value, ["T", "N"]
       static_array.struct = true
-      static_array.declare_instance_var("@buffer", TypeParameter.new(self, static_array, "T"))
+      static_array.declare_instance_var("@buffer", static_array.type_parameter("T"))
       static_array.allowed_in_generics = false
 
       types["String"] = string = @string = NonGenericClassType.new self, self, "String", reference

diff --git 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
       if type_vars = node.type_vars
         free_vars = {} of String => TypeVar
         type_vars.each do |type_var|
-          free_vars[type_var] = TypeParameter.new(program, type.as(GenericType), type_var)
+          free_vars[type_var] = type.as(GenericType).type_parameter(type_var)
         end
       else
         free_vars = nil

diff --git a/src/compiler/crystal/semantic/type_lookup.cr b/src/compiler/crystal/semantic/type_lookup.cr
@@ -68,7 +68,7 @@ class Crystal::Type
       if root.is_a?(GenericType)
         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] ||= root.type_parameter(type_var)
         end
         @free_vars = free_vars
       end
@@ -324,7 +324,7 @@ class Crystal::Type
       end
 
       if (self_type = @self_type).is_a?(GenericType)
-        params = self_type.type_vars.map { |type_var| TypeParameter.new(self_type.program, self_type, type_var).as(TypeVar) }
+        params = self_type.type_vars.map { |type_var| self_type.type_parameter(type_var).as(TypeVar) }
         self_type.instantiate(params)
       else
         @self_type.virtual_type

diff --git a/src/compiler/crystal/types.cr b/src/compiler/crystal/types.cr
@@ -1153,6 +1153,12 @@ module Crystal
     # by the type variables.
     getter(generic_types) { {} of Array(TypeVar) => Type }
 
+    # Returns a TypeParameter relative to this type
+    def type_parameter(name) : TypeParameter
+      type_parameters = @type_parameters ||= {} of String => TypeParameter
+      type_parameters[name] ||= TypeParameter.new(program, self, name)
+    end
+
     def instantiate(type_vars)
       if (instance = generic_types[type_vars]?)
         return instance