commit 38fdced8bb255d3460afefaacce9dc89dab97def (tree)
parent 650185692dc6fb6b9c2c4e591d37cb94410972e1
Author: Matthew Lugg <mlugg@mlugg.co.uk>
Date: Sat, 31 Jan 2026 10:19:12 +0000
Sema: small cleanup
Diffstat:
1 file changed, 60 insertions(+), 58 deletions(-)
diff --git a/src/Sema/type_resolution.zig b/src/Sema/type_resolution.zig
@@ -493,65 +493,67 @@ pub fn resolveUnionLayout(sema: *Sema, union_ty: Type) CompileError!void {
};
defer block.instructions.deinit(gpa);
- // MLUGG TODO: this is fucking ugly bro
- const explicit_enum_tag_ty: ?Type = if (union_obj.is_reified) ty: {
- break :ty switch (union_obj.enum_tag_mode) {
- .explicit => .fromInterned(union_obj.enum_tag_type),
- .auto => null,
- };
- } else ty: {
- const zir_union = sema.code.getUnionDecl(zir_index);
- if (zir_union.kind != .tagged_explicit) {
- break :ty null; // enum tag type will be automatically generated
- }
- // Explicitly specified, so evaluate the enum tag type expression.
- const tag_type_body = zir_union.arg_type_body.?;
- const tag_type_src = block.src(.container_arg);
- block.comptime_reason = .{ .reason = .{
- .src = tag_type_src,
- .r = .{ .simple = .union_enum_tag_type },
- } };
- const type_ref = try sema.resolveInlineBody(&block, tag_type_body, zir_index);
- break :ty try sema.analyzeAsType(&block, tag_type_src, .union_enum_tag_type, type_ref);
- };
- const enum_tag_ty: Type = if (explicit_enum_tag_ty) |enum_tag_ty| ty: {
- if (enum_tag_ty.zigTypeTag(zcu) != .@"enum") return sema.fail(
- &block,
- block.src(.container_arg),
- "expected enum tag type, found '{f}'",
- .{enum_tag_ty.fmt(pt)},
- );
- break :ty enum_tag_ty;
- } else switch (try ip.getGeneratedEnumTagType(gpa, io, pt.tid, .{
- .union_type = union_ty.toIntern(),
- // MLUGG TODO: a bit hacky icl
- .int_tag_mode = mode: {
- if (union_obj.is_reified) break :mode .auto;
- const zir_union = sema.code.getUnionDecl(zir_index);
- if (zir_union.kind != .tagged_enum_explicit) break :mode .auto;
- break :mode .explicit;
+ const enum_tag_ty: Type = switch (union_obj.enum_tag_mode) {
+ .explicit => validated_tag_ty: {
+ // If the union is reified, its enum tag type is already populated. If the union is
+ // declared, we need to evaluate the enum tag type expression (the `E` in `union(E)`).
+ const tag_ty: Type = switch (union_obj.is_reified) {
+ true => .fromInterned(union_obj.enum_tag_type),
+ false => tag_ty: {
+ const zir_union = sema.code.getUnionDecl(zir_index);
+ assert(zir_union.kind == .tagged_explicit); // `Zcu.mapOldZirToNew` guarantees that the ZIR mapping preserves `kind`
+ const tag_type_body = zir_union.arg_type_body.?;
+ const tag_type_src = block.src(.container_arg);
+ block.comptime_reason = .{ .reason = .{
+ .src = tag_type_src,
+ .r = .{ .simple = .union_enum_tag_type },
+ } };
+ const type_ref = try sema.resolveInlineBody(&block, tag_type_body, zir_index);
+ break :tag_ty try sema.analyzeAsType(&block, tag_type_src, .union_enum_tag_type, type_ref);
+ },
+ };
+ // Because the type is explicitly specified, we need to validate it.
+ if (tag_ty.zigTypeTag(zcu) != .@"enum") return sema.fail(
+ &block,
+ block.src(.container_arg),
+ "expected enum tag type, found '{f}'",
+ .{tag_ty.fmt(pt)},
+ );
+ break :validated_tag_ty tag_ty;
},
- .fields_len = @intCast(union_obj.field_types.len),
- })) {
- .existing => |tag_ty| .fromInterned(tag_ty),
- .wip => |wip| tag_ty: {
- errdefer wip.cancel(ip, pt.tid);
- _ = wip.setName(ip, try ip.getOrPutStringFmt(
- gpa,
- io,
- pt.tid,
- "@typeInfo({f}).@\"union\".tag_type.?",
- .{union_obj.name.fmt(ip)},
- .no_embedded_nulls,
- ), .none);
- const new_namespace_index: InternPool.NamespaceIndex = try pt.createNamespace(.{
- .parent = union_obj.namespace.toOptional(),
- .owner_type = wip.index,
- .file_scope = zcu.namespacePtr(union_obj.namespace).file_scope,
- .generation = zcu.generation,
- });
- if (comp.debugIncremental()) try zcu.incremental_debug_state.newType(zcu, wip.index);
- break :tag_ty .fromInterned(wip.finish(ip, new_namespace_index));
+ // If no tag type was specified, we generate one keyed on this union type.
+ .auto => switch (try ip.getGeneratedEnumTagType(gpa, io, pt.tid, .{
+ .union_type = union_ty.toIntern(),
+ // The int tag for this enum is usually inferred---the exception is `union(enum(T))`.
+ .int_tag_mode = switch (union_obj.is_reified) {
+ true => .auto,
+ false => switch (sema.code.getUnionDecl(zir_index).kind) {
+ .tagged_enum_explicit => .auto,
+ else => .explicit,
+ },
+ },
+ .fields_len = @intCast(union_obj.field_types.len),
+ })) {
+ .existing => |tag_ty| .fromInterned(tag_ty),
+ .wip => |wip| tag_ty: {
+ errdefer wip.cancel(ip, pt.tid);
+ _ = wip.setName(ip, try ip.getOrPutStringFmt(
+ gpa,
+ io,
+ pt.tid,
+ "@typeInfo({f}).@\"union\".tag_type.?",
+ .{union_obj.name.fmt(ip)},
+ .no_embedded_nulls,
+ ), .none);
+ const new_namespace_index: InternPool.NamespaceIndex = try pt.createNamespace(.{
+ .parent = union_obj.namespace.toOptional(),
+ .owner_type = wip.index,
+ .file_scope = zcu.namespacePtr(union_obj.namespace).file_scope,
+ .generation = zcu.generation,
+ });
+ if (comp.debugIncremental()) try zcu.incremental_debug_state.newType(zcu, wip.index);
+ break :tag_ty .fromInterned(wip.finish(ip, new_namespace_index));
+ },
},
};
