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don't make anonymous tuple fields referencing comptime vars comptime #25458

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Merged
merged 1 commit into from
Oct 7, 2025
Merged

don't make anonymous tuple fields referencing comptime vars comptime #25458

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29 changes: 27 additions & 2 deletions src/Sema.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -20048,10 +20048,14 @@ fn arrayInitAnon(
const types = try sema.arena.alloc(InternPool.Index, operands.len);
const values = try sema.arena.alloc(InternPool.Index, operands.len);

var any_comptime = false;
const opt_runtime_src = rs: {
var runtime_src: ?LazySrcLoc = null;
for (operands, 0..) |operand, i| {
const operand_src = src; // TODO better source location
const operand_src = block.src(.{ .init_elem = .{
.init_node_offset = src.offset.node_offset.x,
.elem_index = @intCast(i),
} });
const elem = try sema.resolveInst(operand);
types[i] = sema.typeOf(elem).toIntern();
if (Type.fromInterned(types[i]).zigTypeTag(zcu) == .@"opaque") {
Expand All @@ -20066,6 +20070,7 @@ fn arrayInitAnon(
}
if (try sema.resolveValue(elem)) |val| {
values[i] = val.toIntern();
any_comptime = true;
} else {
values[i] = .none;
runtime_src = operand_src;
Expand All @@ -20074,9 +20079,21 @@ fn arrayInitAnon(
break :rs runtime_src;
};

// A field can't be `comptime` if it references a `comptime var` but the aggregate can still be comptime-known.
// Replace these fields with `.none` only for generating the type.
const values_no_comptime = if (!any_comptime) values else blk: {
const new_values = try sema.arena.alloc(InternPool.Index, operands.len);
for (values, new_values) |val, *new_val| {
if (val != .none and Value.fromInterned(val).canMutateComptimeVarState(zcu)) {
new_val.* = .none;
} else new_val.* = val;
}
break :blk new_values;
};

const tuple_ty: Type = .fromInterned(try ip.getTupleType(gpa, pt.tid, .{
.types = types,
.values = values,
.values = values_no_comptime,
}));

const runtime_src = opt_runtime_src orelse {
Expand All @@ -20086,6 +20103,14 @@ fn arrayInitAnon(

try sema.requireRuntimeBlock(block, src, runtime_src);

for (operands, 0..) |operand, i| {
const operand_src = block.src(.{ .init_elem = .{
.init_node_offset = src.offset.node_offset.x,
.elem_index = @intCast(i),
} });
try sema.validateRuntimeValue(block, operand_src, try sema.resolveInst(operand));
}

if (is_ref) {
const target = sema.pt.zcu.getTarget();
const alloc_ty = try pt.ptrTypeSema(.{
Expand Down
9 changes: 9 additions & 0 deletions test/behavior/tuple.zig
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Original file line number Diff line number Diff line change
Expand Up @@ -486,6 +486,15 @@ test "tuple with comptime fields with non empty initializer" {
_ = a;
}

test "anon tuple field referencing comptime var isn't comptime" {
comptime var a: u8 = 0;
const tuple = .{&a};
// field isn't comptime but tuple is still comptime-known
comptime assert(@TypeOf(tuple) == struct { *u8 });
a = 1;
comptime assert(tuple[0].* == 1);
}

test "tuple with runtime value coerced into a slice with a sentinel" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
Expand Down