Commit 8f5db19791dde73e8e969c6ebf821767f1c3e50b | zig

author	Matthew Lugg <mlugg@mlugg.co.uk> 2025-11-29 11:55:36+00:00
committer	Matthew Lugg <mlugg@mlugg.co.uk> 2025-11-29 11:55:36+00:00
log	8f5db19791dde73e8e969c6ebf821767f1c3e50b
tree	dc1337c0ff763087963f524e4f8d6e0c18fb887a
parent	e52232cd570935d7880cbfe52215dbdf0f2d2243
signature	Commit is signed but in an unrecognized format.

Sema: initialize OPV comptime allocs correctly

This was caused a `[0]std.builtin.Type.StructField.Attributes` to be
considered `undefined`, even though that type is OPV so should prefer
its OPV `.{}` over `undefined`.

Resolves: #30039

2 files changed, 12 insertions(+), 1 deletions(-)

src
- Sema.zig
test
- behavior
  - type.zig

src/Sema.zig+3-1

...	...	@@ -175,9 +175,11 @@ const ComptimeAlloc = struct {
175	175
176	176	/// `src` may be `null` if `is_const` will be set.
177	177	fn newComptimeAlloc(sema: Sema, block: Block, src: LazySrcLoc, ty: Type, alignment: Alignment) !ComptimeAllocIndex {
	178	const pt = sema.pt;
	179	const init_val = try sema.typeHasOnePossibleValue(ty) orelse try pt.undefValue(ty);
178	180	const idx = sema.comptime_allocs.items.len;
179	181	try sema.comptime_allocs.append(sema.gpa, .{
180		.val = .{ .interned = try sema.pt.intern(.{ .undef = ty.toIntern() }) },
	182	.val = .{ .interned = init_val.toIntern() },
181	183	.is_const = false,
182	184	.src = src,
183	185	.alignment = alignment,

test/behavior/type.zig+9

...	...	@@ -427,3 +427,12 @@ test "undefined type value" {
427	427	};
428	428	comptime assert(@TypeOf(S.undef_type) == type);
429	429	}
	430
	431	test "reify struct with zero fields through const arrays" {
	432	const names: [0][]const u8 = .{};
	433	const types: [0]type = .{};
	434	const attrs: [0]std.builtin.Type.StructField.Attributes = .{};
	435	const S = @Struct(.auto, null, &names, &types, &attrs);
	436	comptime assert(@typeInfo(S) == .@"struct");
	437	comptime assert(@typeInfo(S).@"struct".fields.len == 0);
	438	}