1const std = @import("std");
 2const expect = std.testing.expect;
 3
 4test "no runtime side effects" {
 5    var data: i32 = 0;
 6    const T = @TypeOf(foo(i32, &data));
 7    try comptime expect(T == i32);
 8    try expect(data == 0);
 9}
10
11fn foo(comptime T: type, ptr: *T) T {
12    ptr.* += 1;
13    return ptr.*;
14}
15
16// test