Fixed #3304: Casting type to itself, when there are subclasses, crash…

…es the compiler
crystal-lang · Sep 14, 2016 · fd2d51f · fd2d51f
1 parent 6bd28f4
commit fd2d51f
Showing 3 changed files with 90 additions and 4 deletions.
diff --git a/spec/compiler/codegen/cast_spec.cr b/spec/compiler/codegen/cast_spec.cr
@@ -289,4 +289,46 @@ describe "Code gen: cast" do
       Bar.new.as(Foo(Int32)).foo
       )).to_i.should eq(2)
   end
+
+  it "upcasts type to virtual (#3304)" do
+    run(%(
+      class Foo
+        def foo
+          1
+        end
+      end
+
+      class Bar < Foo
+        def foo
+          2
+        end
+      end
+
+      Foo.new.as(Foo).foo
+      )).to_i.should eq(1)
+  end
+
+  it "upcasts type to virtual (2) (#3304)" do
+    run(%(
+      class Foo
+        def foo
+          1
+        end
+      end
+
+      class Bar < Foo
+        def foo
+          2
+        end
+      end
+
+      class Gen(T)
+        def self.cast(x)
+          x.as(T)
+        end
+      end
+
+      Gen(Foo).cast(Foo.new).foo
+      )).to_i.should eq(1)
+  end
 end
diff --git a/spec/compiler/codegen/nilable_cast_spec.cr b/spec/compiler/codegen/nilable_cast_spec.cr
@@ -85,4 +85,48 @@ describe "Code gen: nilable cast" do
       foo
       ))
   end
+
+  it "upcasts type to virtual (#3304)" do
+    run(%(
+      class Foo
+        def foo
+          1
+        end
+      end
+
+      class Bar < Foo
+        def foo
+          2
+        end
+      end
+
+      f = Foo.new.as?(Foo)
+      f ? f.foo : 10
+      )).to_i.should eq(1)
+  end
+
+  it "upcasts type to virtual (2) (#3304)" do
+    run(%(
+      class Foo
+        def foo
+          1
+        end
+      end
+
+      class Bar < Foo
+        def foo
+          2
+        end
+      end
+
+      class Gen(T)
+        def self.cast(x)
+          x.as?(T)
+        end
+      end
+
+      f = Gen(Foo).cast(Foo.new)
+      f ? f.foo : 10
+      )).to_i.should eq(1)
+  end
 end
diff --git a/src/compiler/crystal/semantic/bindings.cr b/src/compiler/crystal/semantic/bindings.cr
@@ -296,8 +296,8 @@ module Crystal
         #
         #   1 as Int32 | Float64
         #   Bar.new as Foo # where Bar < Foo
-        if obj_type == filtered_type && obj_type != to_type &&
-           !to_type.is_a?(GenericClassType) && to_type.allowed_in_generics?
+        if obj_type == filtered_type && !to_type.is_a?(GenericClassType) &&
+           to_type.allowed_in_generics?
           filtered_type = to_type
           @upcast = true
         end
@@ -327,8 +327,8 @@ module Crystal
         #
         #   1 as Int32 | Float64
         #   Bar.new as Foo # where Bar < Foo
-        if obj_type == filtered_type && obj_type != to_type &&
-           !to_type.is_a?(GenericClassType) && to_type.allowed_in_generics?
+        if obj_type == filtered_type && !to_type.is_a?(GenericClassType) &&
+           to_type.allowed_in_generics?
           filtered_type = to_type.virtual_type
           @upcast = true
         end