1const std = @import("std");
 2const builtin = @import("builtin");
 3const assert = std.debug.assert;
 4const expect = std.testing.expect;
 5
 6test "truncate u0 to larger integer allowed and has comptime-known result" {
 7    var x: u0 = 0;
 8    _ = &x;
 9    const y = @as(u8, @truncate(x));
10    comptime assert(y == 0);
11}
12
13test "truncate.u0.literal" {
14    const z: u0 = @truncate(0);
15    try expect(z == 0);
16}
17
18test "truncate.u0.const" {
19    const c0: usize = 0;
20    const z: u0 = @truncate(c0);
21    try expect(z == 0);
22}
23
24test "truncate.u0.var" {
25    var d: u8 = 2;
26    _ = &d;
27    const z: u0 = @truncate(d);
28    try expect(z == 0);
29}
30
31test "truncate i0 to larger integer allowed and has comptime-known result" {
32    var x: i0 = 0;
33    _ = &x;
34    const y: i8 = @truncate(x);
35    comptime assert(y == 0);
36}
37
38test "truncate.i0.literal" {
39    const z: i0 = @truncate(0);
40    try expect(z == 0);
41}
42
43test "truncate.i0.const" {
44    const c0: isize = 0;
45    const z: i0 = @truncate(c0);
46    try expect(z == 0);
47}
48
49test "truncate.i0.var" {
50    var d: i8 = 2;
51    _ = &d;
52    const z: i0 = @truncate(d);
53    try expect(z == 0);
54}
55
56test "truncate on comptime integer" {
57    const x: u16 = @truncate(9999);
58    try expect(x == 9999);
59    const y: u16 = @truncate(-21555);
60    try expect(y == 0xabcd);
61    const z: i16 = @truncate(-65537);
62    try expect(z == -1);
63    const w: u1 = @truncate(1 << 100);
64    try expect(w == 0);
65}
66
67test "truncate on vectors" {
68    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
69    if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest;
70    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest;
71    if (builtin.zig_backend == .stage2_sparc64) return error.SkipZigTest; // TODO
72    if (builtin.zig_backend == .stage2_riscv64) return error.SkipZigTest;
73    if (builtin.zig_backend == .stage2_spirv) return error.SkipZigTest;
74
75    const S = struct {
76        fn doTheTest() !void {
77            var v1: @Vector(4, u16) = .{ 0xaabb, 0xccdd, 0xeeff, 0x1122 };
78            _ = &v1;
79            const v2: @Vector(4, u8) = @truncate(v1);
80            try expect(std.mem.eql(u8, &@as([4]u8, v2), &[4]u8{ 0xbb, 0xdd, 0xff, 0x22 }));
81        }
82    };
83    try comptime S.doTheTest();
84    try S.doTheTest();
85}