diff --git a/spec/compiler/parser/to_s_spec.cr b/spec/compiler/parser/to_s_spec.cr
index 4e48797cf268..5e6896ffb77c 100644
--- a/spec/compiler/parser/to_s_spec.cr
+++ b/spec/compiler/parser/to_s_spec.cr
@@ -160,4 +160,5 @@ describe "ASTNode#to_s" do
   expect_to_s %(asm("nop" ::: "e" : "volatile"))
   expect_to_s %[(1..)]
   expect_to_s %[..3]
+  expect_to_s "offsetof(Foo, @bar)"
 end
diff --git a/src/compiler/crystal/syntax/to_s.cr b/src/compiler/crystal/syntax/to_s.cr
index c18be3078de5..51497bbbeb34 100644
--- a/src/compiler/crystal/syntax/to_s.cr
+++ b/src/compiler/crystal/syntax/to_s.cr
@@ -1268,6 +1268,7 @@ module Crystal
       @str << ", "
       node.instance_var.accept(self)
       @str << ')'
+      false
     end
 
     def visit(node : IsA)