The slot kind is now the canonical typed CSharpSlotInfo<T> in Slots, matched by
object identity (the IL SlotInfo model), instead of a parallel SlotKind enum.
CSharpSlotInfo.Kind points at the canonical shared slot; a Slots constant is its
own kind (null Kind, never read -- only per-node slots are asked for their kind),
so there is no self-reference. Child access (GetChild/GetChildren/SetChild,
GetCollectionByKind, AddChild/InsertChild) and the polymorphic
node.Slot.Kind == Slots.X comparisons key on the canonical reference; the
generated SlotKind enum is removed. No behavior change.
Assisted-by: Claude:claude-opus-4-8:Claude Code
GetChildByRole<T> returned default! while it can legitimately yield null (empty slot
or a kind the node does not declare); it now returns T?. Callers that already null-checked
are unchanged; the few that rely on a structural guarantee (name tokens, label identifier,
property accessors) now state it with an explicit !, and MethodDeclaration drops a redundant
cast that the lie required.
Also removes two members left dead by the Role removal: the AddAnnotation override that
only forwarded to the base, and GetCSharpNodeBefore, which ignored 'this' and had no callers.
On the output path, GetChildNodes() allocates a snapshot List per call; the read-only
.Children traversals that never mutate the tree now walk the live FirstChild/NextSibling chain
(O(n), allocation-free, since child indices are cached), an EmptyStatement child check uses
HasChildren, and the label-statement sibling scan breaks on the first match instead of walking
to the end of the block. The generated GetChildNodes snapshot is kept where traversal may mutate.
Assisted-by: Claude:claude-opus-4-8:Claude Code
With every optional slot nullable, the null-object pattern is dead. Generated
non-nullable getters return the backing field directly, which surfaced a last
tier of slots the decompiler legitimately leaves empty (omitted range operands,
an implicitly-typed array creation, unnamed parameters, an unbound generic
argument, and others) and flips them to nullable too. The machinery is then
removed entirely: the per-node null classes, the .Null statics and
VisitNullNode, AstNode.IsNull, the role null object, and Identifier.Null.
AcceptVisitor becomes unconditionally generated, and consumers move from
.IsNull to is null and from unconditional visits to ?.AcceptVisitor.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Optional single-child slots return T? with a real null instead of a role
null-object, taking the C# grammar as the oracle for which slots are optional.
The generator emits the property type as T? and matches it with MatchOptional,
and consumers move from .IsNull to is null / ?.. This covers the optional
statement, member, try-catch, creation-initializer and pattern slots and the
optional NameSlot tokens. A few slots the grammar marks required but the
decompiler legitimately leaves empty (the implicit-element-access target, an
implicitly-typed lambda parameter's type) are flipped to nullable as well.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Turn on #nullable enable across the AST transform pipeline, ahead of
annotating the slot properties themselves. TransformContext now exposes the
nullable CurrentMember/CurrentTypeDefinition/CurrentModule contract already
declared by ITypeResolveContext, and the generated pattern-to-node conversion
returns a non-null node so patterns can be used in collection initializers
without warnings. No IL changes.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Introduce the successor to node.Role for child-slot identity: the generator
emits a CSharpSlotInfo per [Slot], exposed as node.Slot, plus a shared SlotKind
enum for the polymorphic "is this node in an embedded-statement / condition /
base-type slot?" comparisons a per-node identity cannot express. Migrate the
printer and transform position checks from node.Role to node.Slot and
node.Slot.Kind, and read identifier children and role-keyed writes through the
typed properties. Role is still present and is removed later; output is
unchanged.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Siegfried Pammer
Peter Crabtree
Kirill Osenkov
dotnet format
Daniel Grunwald