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const std = @import("std");
const testing = std.testing;
const expect = testing.expect;
const expectEqual = testing.expectEqual;
pub const EmptyStruct = struct {};
test "optional pointer to size zero struct" {
var e = EmptyStruct{};
var o: ?*EmptyStruct = &e;
try expect(o != null);
}
test "equality compare nullable pointers" {
try testNullPtrsEql();
comptime try testNullPtrsEql();
}
fn testNullPtrsEql() !void {
var number: i32 = 1234;
var x: ?*i32 = null;
var y: ?*i32 = null;
try expect(x == y);
y = &number;
try expect(x != y);
try expect(x != &number);
try expect(&number != x);
x = &number;
try expect(x == y);
try expect(x == &number);
try expect(&number == x);
}
test "address of unwrap optional" {
const S = struct {
const Foo = struct {
a: i32,
};
var global: ?Foo = null;
pub fn getFoo() anyerror!*Foo {
return &global.?;
}
};
S.global = S.Foo{ .a = 1234 };
const foo = S.getFoo() catch unreachable;
try expect(foo.a == 1234);
}
test "equality compare optional with non-optional" {
try test_cmp_optional_non_optional();
comptime try test_cmp_optional_non_optional();
}
fn test_cmp_optional_non_optional() !void {
var ten: i32 = 10;
var opt_ten: ?i32 = 10;
var five: i32 = 5;
var int_n: ?i32 = null;
try expect(int_n != ten);
try expect(opt_ten == ten);
try expect(opt_ten != five);
// test evaluation is always lexical
// ensure that the optional isn't always computed before the non-optional
var mutable_state: i32 = 0;
_ = blk1: {
mutable_state += 1;
break :blk1 @as(?f64, 10.0);
} != blk2: {
try expect(mutable_state == 1);
break :blk2 @as(f64, 5.0);
};
_ = blk1: {
mutable_state += 1;
break :blk1 @as(f64, 10.0);
} != blk2: {
try expect(mutable_state == 2);
break :blk2 @as(?f64, 5.0);
};
}
test "passing an optional integer as a parameter" {
const S = struct {
fn entry() bool {
var x: i32 = 1234;
return foo(x);
}
fn foo(x: ?i32) bool {
return x.? == 1234;
}
};
try expect(S.entry());
comptime try expect(S.entry());
}
test "unwrap function call with optional pointer return value" {
const S = struct {
fn entry() !void {
try expect(foo().?.* == 1234);
try expect(bar() == null);
}
const global: i32 = 1234;
fn foo() ?*const i32 {
return &global;
}
fn bar() ?*i32 {
return null;
}
};
try S.entry();
comptime try S.entry();
}
test "nested orelse" {
const S = struct {
fn entry() !void {
try expect(func() == null);
}
fn maybe() ?Foo {
return null;
}
fn func() ?Foo {
const x = maybe() orelse
maybe() orelse
return null;
_ = x;
unreachable;
}
const Foo = struct {
field: i32,
};
};
try S.entry();
comptime try S.entry();
}
test "self-referential struct through a slice of optional" {
const S = struct {
const Node = struct {
children: []?Node,
data: ?u8,
fn new() Node {
return Node{
.children = undefined,
.data = null,
};
}
};
};
var n = S.Node.new();
try expect(n.data == null);
}
test "assigning to an unwrapped optional field in an inline loop" {
comptime var maybe_pos_arg: ?comptime_int = null;
inline for ("ab") |x| {
_ = x;
maybe_pos_arg = 0;
if (maybe_pos_arg.? != 0) {
@compileError("bad");
}
maybe_pos_arg.? = 10;
}
}
test "coerce an anon struct literal to optional struct" {
const S = struct {
const Struct = struct {
field: u32,
};
fn doTheTest() !void {
var maybe_dims: ?Struct = null;
maybe_dims = .{ .field = 1 };
try expect(maybe_dims.?.field == 1);
}
};
try S.doTheTest();
comptime try S.doTheTest();
}
test "optional with void type" {
const Foo = struct {
x: ?void,
};
var x = Foo{ .x = null };
try expect(x.x == null);
}
test "0-bit child type coerced to optional return ptr result location" {
const S = struct {
fn doTheTest() !void {
var y = Foo{};
var z = y.thing();
try expect(z != null);
}
const Foo = struct {
pub const Bar = struct {
field: *Foo,
};
pub fn thing(self: *Foo) ?Bar {
return Bar{ .field = self };
}
};
};
try S.doTheTest();
comptime try S.doTheTest();
}
test "0-bit child type coerced to optional" {
const S = struct {
fn doTheTest() !void {
var it: Foo = .{
.list = undefined,
};
try expect(it.foo() != null);
}
const Empty = struct {};
const Foo = struct {
list: [10]Empty,
fn foo(self: *Foo) ?*Empty {
const data = &self.list[0];
return data;
}
};
};
try S.doTheTest();
comptime try S.doTheTest();
}
test "array of optional unaligned types" {
const Enum = enum { one, two, three };
const SomeUnion = union(enum) {
Num: Enum,
Other: u32,
};
const values = [_]?SomeUnion{
SomeUnion{ .Num = .one },
SomeUnion{ .Num = .two },
SomeUnion{ .Num = .three },
SomeUnion{ .Num = .one },
SomeUnion{ .Num = .two },
SomeUnion{ .Num = .three },
};
// The index must be a runtime value
var i: usize = 0;
try expectEqual(Enum.one, values[i].?.Num);
i += 1;
try expectEqual(Enum.two, values[i].?.Num);
i += 1;
try expectEqual(Enum.three, values[i].?.Num);
i += 1;
try expectEqual(Enum.one, values[i].?.Num);
i += 1;
try expectEqual(Enum.two, values[i].?.Num);
i += 1;
try expectEqual(Enum.three, values[i].?.Num);
}
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