diff --git a/internal/printer/nodes.go b/internal/printer/nodes.go
index b89324d195c9d268d96891510897f6431260aff1..1d531add88433cd0420edb45b8374fc3f2fc6b77 100644
--- a/internal/printer/nodes.go
+++ b/internal/printer/nodes.go
@@ -386,7 +386,9 @@ func (p *printer) parameters(fields *ast.FieldList) {
 
 func (p *printer) signature(params, result *ast.FieldList) {
 	if params != nil {
-		p.parameters(params)
+		if params.Opening != token.NoPos {
+			p.parameters(params)
+		}
 	} else {
 		p.print(token.LPAREN, token.RPAREN)
 	}