diff --git a/hatmill.go b/hatmill.go
index 96d7191..2890b65 100644
--- a/hatmill.go
+++ b/hatmill.go
@@ -2,8 +2,6 @@ package hatmill
 
 import "io"
 
-//go:generate go run ./internal/codegen/codegen.go -input htmldefs.json -output html5/generated.go -package html5 -import
-
 // Term represents a fragment of HTML markup, and is one of VoidElement, ParentElement, or Text.
 type Term interface {
 	io.WriterTo
diff --git a/htmldefs.json b/html5/defs.json
similarity index 100%
rename from htmldefs.json
rename to html5/defs.json
diff --git a/html5/html5.go b/html5/html5.go
index 3ed436d..4a3fa5f 100644
--- a/html5/html5.go
+++ b/html5/html5.go
@@ -1,5 +1,7 @@
 package html5
 
+//go:generate go run ../internal/codegen/codegen.go -input defs.json -output generated.go -package html5 -import
+
 import "gitlab.codemonkeysoftware.net/b/hatmill"
 
 // Data creates an attribute of the form "data-suffix='value'".