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Sema: fix access of inactive union field when enum and union fields are in different order

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Closes #12667
This commit is contained in:
Veikka Tuominen 2022-08-29 00:40:02 +03:00 • committed by Andrew Kelley
parent 15cc4514e0
commit a4b52ccd9f
2 changed files with 33 additions and 10 deletions
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20
src/Sema.zig
View file

@ -21892,17 +21892,18 @@ fn unionFieldPtr(
if (union_val.isUndef()) {
return sema.failWithUseOfUndef(block, src);
}
const enum_field_index = union_obj.tag_ty.enumFieldIndex(field_name).?;
const tag_and_val = union_val.castTag(.@"union").?.data;
var field_tag_buf: Value.Payload.U32 = .{
.base = .{ .tag = .enum_field_index },
.data = field_index,
.data = @intCast(u32, enum_field_index),
};
const field_tag = Value.initPayload(&field_tag_buf.base);
const tag_matches = tag_and_val.tag.eql(field_tag, union_obj.tag_ty, sema.mod);
if (!tag_matches) {
const msg = msg: {
const active_index = tag_and_val.tag.castTag(.enum_field_index).?.data;
const active_field_name = union_obj.fields.keys()[active_index];
const active_field_name = union_obj.tag_ty.enumFieldName(active_index);
const msg = try sema.errMsg(block, src, "access of union field '{s}' while field '{s}' is active", .{ field_name, active_field_name });
errdefer msg.destroy(sema.gpa);
try sema.addDeclaredHereNote(msg, union_ty);
@ -21927,12 +21928,11 @@ fn unionFieldPtr(
if (!initializing and union_obj.layout == .Auto and block.wantSafety() and
union_ty.unionTagTypeSafety() != null and union_obj.fields.count() > 1)
{
const enum_ty = union_ty.unionTagTypeHypothetical();
const wanted_tag_val = try Value.Tag.enum_field_index.create(sema.arena, field_index);
const wanted_tag = try sema.addConstant(enum_ty, wanted_tag_val);
const wanted_tag = try sema.addConstant(union_obj.tag_ty, wanted_tag_val);
// TODO would it be better if get_union_tag supported pointers to unions?
const union_val = try block.addTyOp(.load, union_ty, union_ptr);
const active_tag = try block.addTyOp(.get_union_tag, enum_ty, union_val);
const active_tag = try block.addTyOp(.get_union_tag, union_obj.tag_ty, union_val);
const ok = try block.addBinOp(.cmp_eq, active_tag, wanted_tag);
try sema.addSafetyCheck(block, ok, .inactive_union_field);
}
@ -21963,9 +21963,10 @@ fn unionFieldVal(
if (union_val.isUndef()) return sema.addConstUndef(field.ty);
const tag_and_val = union_val.castTag(.@"union").?.data;
const enum_field_index = union_obj.tag_ty.enumFieldIndex(field_name).?;
var field_tag_buf: Value.Payload.U32 = .{
.base = .{ .tag = .enum_field_index },
.data = field_index,
.data = @intCast(u32, enum_field_index),
};
const field_tag = Value.initPayload(&field_tag_buf.base);
const tag_matches = tag_and_val.tag.eql(field_tag, union_obj.tag_ty, sema.mod);
@ -21976,7 +21977,7 @@ fn unionFieldVal(
} else {
const msg = msg: {
const active_index = tag_and_val.tag.castTag(.enum_field_index).?.data;
const active_field_name = union_obj.fields.keys()[active_index];
const active_field_name = union_obj.tag_ty.enumFieldName(active_index);
const msg = try sema.errMsg(block, src, "access of union field '{s}' while field '{s}' is active", .{ field_name, active_field_name });
errdefer msg.destroy(sema.gpa);
try sema.addDeclaredHereNote(msg, union_ty);
@ -22001,10 +22002,9 @@ fn unionFieldVal(
if (union_obj.layout == .Auto and block.wantSafety() and
union_ty.unionTagTypeSafety() != null and union_obj.fields.count() > 1)
{
const enum_ty = union_ty.unionTagTypeHypothetical();
const wanted_tag_val = try Value.Tag.enum_field_index.create(sema.arena, field_index);
const wanted_tag = try sema.addConstant(enum_ty, wanted_tag_val);
const active_tag = try block.addTyOp(.get_union_tag, enum_ty, union_byval);
const wanted_tag = try sema.addConstant(union_obj.tag_ty, wanted_tag_val);
const active_tag = try block.addTyOp(.get_union_tag, union_obj.tag_ty, union_byval);
const ok = try block.addBinOp(.cmp_eq, active_tag, wanted_tag);
try sema.addSafetyCheck(block, ok, .inactive_union_field);
}

23
test/cases/compile_errors/access_inactive_union_field_comptime.zig Normal file
View file

@ -0,0 +1,23 @@
const Enum = enum(u32) { a, b };
const TaggedUnion = union(Enum) {
b: []const u8,
a: []const u8,
};
pub export fn entry() void {
const result = TaggedUnion{ .b = "b" };
_ = result.b;
_ = result.a;
}
pub export fn entry1() void {
const result = TaggedUnion{ .b = "b" };
_ = &result.b;
_ = &result.a;
}
// error
// backend=stage2
// target=native
//
// :9:15: error: access of union field 'a' while field 'b' is active
// :2:21: note: union declared here
// :14:16: error: access of union field 'a' while field 'b' is active