checker: fix warning at comptime call (#8248)

vlib/v/checker/checker.v

@@ -3605,6 +3605,11 @@ fn (mut c Checker) comptime_call(mut node ast.ComptimeCall) table.Type {
 	if node.method_name == 'html' {
 		return c.table.find_type_idx('vweb.Result')
 	}
+	mut var := c.fn_scope.objects[node.method_name]
+	if mut var is ast.Var {
+		var.is_used = true
+		c.fn_scope.objects[node.method_name] = var
+	}
 	return table.string_type
 }
 

vlib/v/checker/tests/comptime_call_no_unused_var.out

@@ -0,0 +1 @@
+

vlib/v/checker/tests/comptime_call_no_unused_var.vv

@@ -0,0 +1,11 @@
+struct Test {}
+
+fn (test Test) print() {
+	println('test')
+}
+
+fn main() {
+	test := Test{}
+	abc := 'print'
+	test.$abc()
+}