538349611e
A comptime-constructed type with NO members is now VALID for every kind
(empty struct, empty tuple, empty enum, empty tagged_union) — only a bare
`declare("X")` placeholder that is never completed by a matching `define`
stays rejected (it would panic codegen).
- comptime_vm.zig registerTypeVm: drop the blanket "a type with no members
is never valid" rejection. The per-kind loops are vacuous for an empty
member list and the dup-name checks stay correct.
- types.zig TaggedUnionInfo: add `defined: bool = true`. Every real
construction (normal unions, error sets, register_type completion) is
"defined" by default; only the two declare-PLACEHOLDER sites set it false:
comptime_vm.declareNominal and lower/comptime.preregisterForwardTypes.
- lower/comptime.checkComptimeTypeResult: reject on `!defined` (never-defined
placeholder) instead of `fields.len == 0`, so an explicitly-defined empty
union passes through while a never-completed declare is still gated.
- types.zig typeSizeBytes(tagged_union): floor the payload area at 8 bytes
when no field carries a payload, mirroring the LLVM lowering — fixes a
verifySizes panic on an empty/all-void tagged_union (IR sized to tag-only,
LLVM laid out tag + [8 x i8]).
Tests:
- examples/1179: repurposed from "empty enum rejected" (now valid) to the
never-defined `declare` case (the remaining rejection); preserves its
issue-0140 regression role.
- examples/1180 (duplicate variant): still rejected, unchanged output.
- examples/0641 (new): construct empty struct/tuple/enum/tagged_union via
define/declare; instantiate the constructible ones; exit 0.
2 lines
51 B
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2 lines
51 B
Plaintext
empty struct/tuple/enum/tagged_union are all valid
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