Fixed #229: Can't change block context if defined within module context

spec/compiler/type_inference/yield_with_scope_spec.cr

@@ -51,4 +51,23 @@ describe "Type inference: yield with scope" do
     mod, input = result.program, result.node as Expressions
     (input.last as Call).block.not_nil!.body.type.should eq(mod.float64)
   end
+
+  it "passes #229" do
+    assert_type(%(
+      class Foo
+        def foo
+          1
+        end
+      end
+
+      def a
+        with Foo.new yield
+      end
+
+      module Bar
+        x = a { foo }
+      end
+      x
+      )) { int32 }
+  end
 end

src/compiler/crystal/semantic/type_inference.cr

@@ -645,7 +645,7 @@ module Crystal
       block_visitor.fun_literal_context = @fun_literal_context
 
       block_scope = node.scope || @scope
-      block_scope = current_type.metaclass unless current_type.is_a?(Program)
+      block_scope ||= current_type.metaclass unless current_type.is_a?(Program)
 
       block_visitor.scope = block_scope