Fixed #3977: Invalid memory access when using uninitialized Type

Ary Borenszweig · Ary Borenszweig · commit 1e2dc907101a · 2017-02-08T18:36:28.000-03:00
diff --git a/spec/compiler/semantic/uninitialized_spec.cr b/spec/compiler/semantic/uninitialized_spec.cr
@@ -41,6 +41,20 @@ describe "Semantic: uninitialized" do
       "can't declare variable of generic non-instantiated type Foo"
   end
 
+  it "errors if declaring generic type without type vars (with class var)" do
+    assert_error %(
+      class Foo(T)
+      end
+
+      class Bar
+        @@x = uninitialized Foo
+      end
+
+      Bar.new
+      ),
+      "can't declare variable of generic non-instantiated type Foo"
+  end
+
   it "errors if declares var and then assigns other type" do
     assert_error %(
       x = uninitialized Int32
diff --git a/spec/compiler/semantic/var_spec.cr b/spec/compiler/semantic/var_spec.cr
@@ -128,4 +128,14 @@ describe "Semantic: var" do
       ),
       "variable 'a' already declared"
   end
+
+  it "errors if declaring generic type without type vars (with local var)" do
+    assert_error %(
+      class Foo(T)
+      end
+
+      x : Foo
+      ),
+      "can't declare variable of generic non-instantiated type Foo"
+  end
 end
diff --git a/src/compiler/crystal/semantic/main_visitor.cr b/src/compiler/crystal/semantic/main_visitor.cr
@@ -363,7 +363,8 @@ module Crystal
         check_not_a_constant(node.declared_type)
 
         if declared_type = node.declared_type.type?
-          meta_var.freeze_type = declared_type
+          var_type = check_declare_var_type node, declared_type, "a variable"
+          meta_var.freeze_type = var_type
         else
           node.raise "can't infer type of type declaration"
         end
diff --git a/src/compiler/crystal/syntax/ast.cr b/src/compiler/crystal/syntax/ast.cr
@@ -1413,6 +1413,8 @@ module Crystal
         var.name.size
       when InstanceVar
         var.name.size
+      when ClassVar
+        var.name.size
       else
         raise "can't happen"
       end
