stage1: Make sure union(enum(T)) is valid

The T type should be wide enough to fit values in the  0...num field
range.

Closes #6988
This commit is contained in:
LemonBoy 2020-11-05 20:40:20 +01:00 committed by Andrew Kelley
parent f85d719952
commit 78840c4ab2
2 changed files with 47 additions and 0 deletions

View File

@ -3178,6 +3178,22 @@ static Error resolve_union_zero_bits(CodeGen *g, ZigType *union_type) {
union_type->data.unionation.resolve_status = ResolveStatusInvalid;
return ErrorSemanticAnalyzeFail;
}
if (tag_int_type->id == ZigTypeIdInt) {
BigInt bi;
bigint_init_unsigned(&bi, field_count - 1);
if (!bigint_fits_in_bits(&bi,
tag_int_type->data.integral.bit_count,
tag_int_type->data.integral.is_signed))
{
ErrorMsg *msg = add_node_error(g, enum_type_node,
buf_sprintf("specified integer tag type cannot represent every field"));
add_error_note(g, msg, enum_type_node,
buf_sprintf("type %s cannot fit values in range 0...%" PRIu32,
buf_ptr(&tag_int_type->name), field_count - 1));
union_type->data.unionation.resolve_status = ResolveStatusInvalid;
return ErrorSemanticAnalyzeFail;
}
}
} else {
tag_int_type = get_smallest_unsigned_int_type(g, field_count - 1);
}

View File

@ -2,6 +2,37 @@ const tests = @import("tests.zig");
const std = @import("std");
pub fn addCases(cases: *tests.CompileErrorContext) void {
cases.add("union with too small explicit signed tag type",
\\const U = union(enum(i2)) {
\\ A: u8,
\\ B: u8,
\\ C: u8,
\\ D: u8,
\\};
\\export fn entry() void {
\\ _ = U{ .D = 1 };
\\}
, &[_][]const u8{
"tmp.zig:1:22: error: specified integer tag type cannot represent every field",
"tmp.zig:1:22: note: type i2 cannot fit values in range 0...3",
});
cases.add("union with too small explicit unsigned tag type",
\\const U = union(enum(u2)) {
\\ A: u8,
\\ B: u8,
\\ C: u8,
\\ D: u8,
\\ E: u8,
\\};
\\export fn entry() void {
\\ _ = U{ .E = 1 };
\\}
, &[_][]const u8{
"tmp.zig:1:22: error: specified integer tag type cannot represent every field",
"tmp.zig:1:22: note: type u2 cannot fit values in range 0...4",
});
cases.add("unreachable executed at comptime",
\\fn foo(comptime x: i32) i32 {
\\ comptime {