HTML-41 Don't print the output of variable assigns to the IO

spec/instance_template/variable_assigns_spec.cr

@@ -0,0 +1,27 @@
+require "../spec_helper"
+
+module ToHtml::InstanceTemplate::VariableAssignsSpec
+  class MyView
+    def something_expensive
+      ["expensive", "strings"]
+    end
+
+    ToHtml.instance_template do
+      tmp = something_expensive
+      tmp.each do |item|
+        div { item }
+      end
+    end
+  end
+
+  describe "MyView#to_html" do
+    it "should not render the variable assignment" do
+      expected = <<-HTML.squish
+      <div>expensive</div>
+      <div>strings</div>
+      HTML
+
+      MyView.new.to_html.should eq(expected)
+    end
+  end
+end

src/instance_template.cr

@@ -100,6 +100,9 @@ module ToHtml
           {% end %}
       {% end %}
       end
+    {% elsif blk.body.is_a?(Assign) %}
+      # Don't print this to the IO
+      {{blk.body}}
     {% elsif blk.body.is_a?(Yield) %}
       yield {{io}}, {{indent_level}}
     {% elsif blk.body.is_a?(Nop) %}