Fixed #4054: "is not a type, it's a constant" error

Ary Borenszweig · Ary Borenszweig · commit a2ffa050b54d · 2017-03-02T18:29:52.000-03:00
diff --git a/spec/compiler/semantic/instance_var_spec.cr b/spec/compiler/semantic/instance_var_spec.cr
@@ -4625,4 +4625,19 @@ describe "Semantic: instance var" do
       ),
       "Can't infer the type of instance variable '@bar' of Foo"
   end
+
+  it "can't infer type when using operation on const (#4054)" do
+    assert_error %(
+      class Foo
+        BAR = 5
+
+        def initialize
+          @baz = BAR + 5
+        end
+      end
+
+      Foo.new
+      ),
+      "Can't infer the type of instance variable '@baz' of Foo"
+  end
 end
diff --git a/src/compiler/crystal/semantic/type_lookup.cr b/src/compiler/crystal/semantic/type_lookup.cr
@@ -81,7 +81,11 @@ class Crystal::Type
 
       case type_var
       when Const
-        node.raise "#{type_var} is not a type, it's a constant"
+        if @raise
+          node.raise "#{type_var} is not a type, it's a constant"
+        else
+          return nil
+        end
       when Type
         return type_var
       end
