diff --git a/vlib/v/gen/c/for.v b/vlib/v/gen/c/for.v
index 0e31f3e689..50a802ed6c 100644
--- a/vlib/v/gen/c/for.v
+++ b/vlib/v/gen/c/for.v
@@ -322,7 +322,7 @@ fn (mut g Gen) for_in_stmt(node_ ast.ForInStmt) {
 				g.writeln('\t${styp} ${c_name(node.val_var)};')
 				g.writeln('\tmemcpy(*(${styp}*)${c_name(node.val_var)}, (byte*)${cond_var}[${idx}], sizeof(${styp}));')
 			} else {
-				mut styp := g.styp(node.val_type)
+				styp := g.styp(node.val_type)
 				g.write('\t${styp} ${c_name(node.val_var)}')
 			}
 			if !is_fixed_array {
diff --git a/vlib/v/gen/c/str.v b/vlib/v/gen/c/str.v
index b7c736c606..6d3bab7f05 100644
--- a/vlib/v/gen/c/str.v
+++ b/vlib/v/gen/c/str.v
@@ -120,7 +120,7 @@ fn (mut g Gen) gen_expr_to_string(expr ast.Expr, etype ast.Type) {
 		exp_typ := if unwrap_option { typ.clear_flag(.option) } else { typ }
 		is_dump_expr := expr is ast.DumpExpr
 		is_var_mut := expr.is_auto_deref_var()
-		mut str_fn_name := g.get_str_fn(exp_typ)
+		str_fn_name := g.get_str_fn(exp_typ)
 		temp_var_needed := expr is ast.CallExpr
 			&& (expr.return_type.is_ptr() || g.table.sym(expr.return_type).is_c_struct())
 		mut tmp_var := ''
@@ -171,7 +171,7 @@ fn (mut g Gen) gen_expr_to_string(expr ast.Expr, etype ast.Type) {
 			}
 		} else if is_ptr && typ.has_flag(.option) {
 			if typ.has_flag(.option_mut_param_t) {
-				g.write('/**/*')
+				g.write('*')
 			} else {
 				g.write('*(${g.styp(typ)}*)&')
 			}
diff --git a/vlib/v/tests/options/option_for_mut_test.v b/vlib/v/tests/options/option_for_mut_test.v
new file mode 100644
index 0000000000..37650f5f5a
--- /dev/null
+++ b/vlib/v/tests/options/option_for_mut_test.v
@@ -0,0 +1,15 @@
+module main
+
+fn test_main() {
+	mut data := [3]?int{}
+
+	for mut d in data {
+		d = ?int(1)
+		assert '${d}' == 'Option(1)'
+	}
+
+	for i in 0 .. data.len {
+		data[i] = ?int(3)
+	}
+	assert '${data}' == '[Option(3), Option(3), Option(3)]'
+}