Commit 283afb50b56fb8a2c288d2452bdf6e595a1bbb06 | zig

author	Matthew Lugg <mlugg@mlugg.co.uk> 2023-08-21 02:27:11+01:00
committer	Veikka Tuominen <git@vexu.eu> 2023-08-21 11:47:31+03:00
log	283afb50b56fb8a2c288d2452bdf6e595a1bbb06
tree	074cfa8a07a8763d455289a20fc0b08e1b0395be
parent	411462e1cdac518ccb67a8dd7aa5ef93332f8d19

AstGen: disallow '-0' integer literal

The intent here is ambiguous: this resolves to the comptime_int '0', but
it's likely the user meant to use a floating-point literal.

Resolves: #16890

5 files changed, 22 insertions(+), 18 deletions(-)

lib
- std
  - math
    big
    int_test.zig
    pow.zig
src
- AstGen.zig
test
- behavior
  - bitcast.zig
- cases
  - compile_errors
    negative_zero_literal.zig

lib/std/math/big/int_test.zig-13

...	...	@@ -2317,17 +2317,6 @@ test "big.int bitwise xor single negative simple" {
2317	2317	try testing.expect((try a.to(i64)) == -0x2efed94fcb932ef9);
2318	2318	}
2319	2319
2320		test "big.int bitwise xor single negative zero" {
2321		var a = try Managed.initSet(testing.allocator, 0);
2322		defer a.deinit();
2323		var b = try Managed.initSet(testing.allocator, -0);
2324		defer b.deinit();
2325
2326		try a.bitXor(&a, &b);
2327
2328		try testing.expect(a.eqlZero());
2329		}
2330
2331	2320	test "big.int bitwise xor single negative multi-limb" {
2332	2321	var a = try Managed.initSet(testing.allocator, -0x9849c6e7a10d66d0e4260d4846254c32);
2333	2322	defer a.deinit();
...	...	@@ -2687,8 +2676,6 @@ test "big int popcount" {
2687	2676	try a.set(0);
2688	2677	try popCountTest(&a, 0, 0);
2689	2678	try popCountTest(&a, 567, 0);
2690		try a.set(-0);
2691		try popCountTest(&a, 0, 0);
2692	2679
2693	2680	try a.set(1);
2694	2681	try popCountTest(&a, 1, 1);

lib/std/math/pow.zig+2-2

...	...	@@ -209,8 +209,8 @@ test "math.pow.special" {
209	209	try expect(pow(f32, -45, 1.0) == -45);
210	210	try expect(math.isNan(pow(f32, math.nan(f32), 5.0)));
211	211	try expect(math.isPositiveInf(pow(f32, -math.inf(f32), 0.5)));
212		try expect(math.isPositiveInf(pow(f32, -0, -0.5)));
213		try expect(pow(f32, -0, 0.5) == 0);
	212	try expect(math.isPositiveInf(pow(f32, -0.0, -0.5)));
	213	try expect(pow(f32, -0.0, 0.5) == 0);
214	214	try expect(math.isNan(pow(f32, 5.0, math.nan(f32))));
215	215	try expect(math.isPositiveInf(pow(f32, 0.0, -1.0)));
216	216	//expect(math.isNegativeInf(pow(f32, -0.0, -3.0))); TODO is this required?

src/AstGen.zig+9-1

...	...	@@ -7270,7 +7270,15 @@ fn numberLiteral(gz: *GenZir, ri: ResultInfo, node: Ast.Node.Index, source_node:
7270	7270
7271	7271	const result: Zir.Inst.Ref = switch (std.zig.parseNumberLiteral(bytes)) {
7272	7272	.int => \|num\| switch (num) {
7273		0 => .zero,
	7273	0 => if (sign == .positive) .zero else return astgen.failTokNotes(
	7274	num_token,
	7275	"integer literal '-0' is ambiguous",
	7276	.{},
	7277	&.{
	7278	try astgen.errNoteTok(num_token, "use '0' for an integer zero", .{}),
	7279	try astgen.errNoteTok(num_token, "use '-0.0' for a floating-point signed zero", .{}),
	7280	},
	7281	),
7274	7282	1 => .one,
7275	7283	else => try gz.addInt(num),
7276	7284	},

test/behavior/bitcast.zig-2

...	...	@@ -63,8 +63,6 @@ fn testBitCast(comptime N: usize) !void {
63	63	try expect(conv_uN(N, 0) == 0);
64	64	try expect(conv_iN(N, 0) == 0);
65	65
66		try expect(conv_iN(N, -0) == 0);
67
68	66	if (N > 24) {
69	67	try expect(conv_uN(N, 0xf23456) == 0xf23456);
70	68	}

test/cases/compile_errors/negative_zero_literal.zig created+11

...	...	@@ -0,0 +1,11 @@
	1	export fn foo() void {
	2	_ = -0;
	3	}
	4
	5	// error
	6	// backend=stage2
	7	// target=native
	8	//
	9	// :2:10: error: integer literal '-0' is ambiguous
	10	// :2:10: note: use '0' for an integer zero
	11	// :2:10: note: use '-0.0' for a floating-point signed zero