Fixed #3014: Bug when casting from a pointer to abstract class

crystal-lang · Jul 19, 2016 · d777ce2 · d777ce2
1 parent 3445d6d
commit d777ce2
Showing 4 changed files with 51 additions and 38 deletions.
diff --git a/spec/compiler/codegen/cast_spec.cr b/spec/compiler/codegen/cast_spec.cr
@@ -255,4 +255,20 @@ describe "Code gen: cast" do
       123
       )).to_i.should eq(123)
   end
+
+  it "can cast from Void* to virtual type (#3014)" do
+    run(%(
+      abstract class A
+        abstract def hi
+      end
+
+      class B < A
+        def hi
+          42
+        end
+      end
+
+      B.new.as(Void*).as(A).hi
+      )).to_i.should eq(42)
+  end
 end
diff --git a/spec/compiler/type_inference/cast_spec.cr b/spec/compiler/type_inference/cast_spec.cr
@@ -278,4 +278,16 @@ describe "Type inference: cast" do
       ),
       "can't cast to Class yet"
   end
+
+  it "can cast from Void* to virtual type (#3014)" do
+    assert_type(%(
+      abstract class A
+      end
+
+      class B < A
+      end
+
+      B.new.as(Void*).as(A)
+      )) { types["A"].virtual_type! }
+  end
 end
diff --git a/src/compiler/crystal/codegen/codegen.cr b/src/compiler/crystal/codegen/codegen.cr
@@ -1085,7 +1085,7 @@ module Crystal
       last_value = @last
 
       obj_type = node.obj.type
-      to_type = node.to.type
+      to_type = node.to.type.virtual_type
 
       if to_type.pointer?
         if obj_type.nil_type?

diff --git a/src/compiler/crystal/semantic/ast.cr b/src/compiler/crystal/semantic/ast.cr
@@ -567,19 +567,10 @@ module Crystal
     property? upcast = false
 
     def update(from = nil)
-      to_type = to.type
-
       obj_type = obj.type?
+      to_type = to.type
 
-      # If we don't know what type we are casting from, leave it as the to_type
-      unless obj_type
-        self.type = to_type.virtual_type
-        return
-      end
-
-      if obj_type.pointer? || to_type.pointer?
-        self.type = to_type
-      else
+      if obj_type && !(obj_type.pointer? || to_type.pointer?)
         filtered_type = obj_type.filter_by(to_type)
 
         # If the filtered type didn't change it means that an
@@ -588,16 +579,16 @@ 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)
-          filtered_type = to_type.virtual_type
+          filtered_type = to_type
           @upcast = true
         end
+      end
 
-        # If we don't have a matching type, leave it as the to_type:
-        # later (in after type inference) we will check again.
-        filtered_type ||= to_type.virtual_type
+      # If we don't have a matching type, leave it as the to_type:
+      # later (in after type inference) we will check again.
+      filtered_type ||= to_type
 
-        self.type = filtered_type
-      end
+      self.type = filtered_type.virtual_type
     end
   end
 
@@ -606,33 +597,27 @@ module Crystal
     getter! non_nilable_type : Type
 
     def update(from = nil)
-      to_type = to.type
-
       obj_type = obj.type?
+      to_type = to.type
 
-      # If we don't know what type we are casting from, leave it as nilable to_type
-      unless obj_type
-        @non_nilable_type = non_nilable_type = to_type.virtual_type
-
-        self.type = to_type.program.nilable(non_nilable_type)
-        return
-      end
-
-      filtered_type = obj_type.filter_by(to_type)
+      if obj_type
+        filtered_type = obj_type.filter_by(to_type)
 
-      # If the filtered type didn't change it means that an
-      # upcast is being made, for example:
-      #
-      #   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)
-        filtered_type = to_type.virtual_type
-        @upcast = true
+        # If the filtered type didn't change it means that an
+        # upcast is being made, for example:
+        #
+        #   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)
+          filtered_type = to_type.virtual_type
+          @upcast = true
+        end
       end
 
       # If we don't have a matching type, leave it as the to_type:
       # later (in after type inference) we will check again.
-      filtered_type ||= to_type.virtual_type
+      filtered_type ||= to_type
+      filtered_type = filtered_type.virtual_type
 
       @non_nilable_type = filtered_type