The C# syntax tree's name accessors (ParameterDeclaration.Name, GotoStatement.Label,
catch variable, query continuations, ...) are convenience strings over a backing Identifier
token. Names that may be absent are now typed string? and read as null when absent, instead of
a non-null empty-string sentinel; required names stay non-null string. The backing token slot's
nullability follows, and an empty or null assignment clears the token (empty == absent).
Because the property type now carries optionality, the separate [NameSlot] attribute and its
nullOnEmpty flag are redundant: a [Slot] on a string property is a name (child slots are
AstNode-typed, so the type disambiguates), and the generator infers optionality from the
declared nullable annotation -- which a string? declaration already requires #nullable for. The
repeated empty-to-null setter body becomes Identifier.CreateIfNotEmpty. To make the annotation
readable, #nullable enable is turned on across the syntax node files (the directive the inferred
optionality depends on), with the attendant local nullability fixups. Consumers that feed a name
into a non-null slot assert it where the variable structurally has a name.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Nodes use nullable reference types now, so the generated null-object
node and its hasNullNode / NeedsNullNode / NullNodeBaseCtorParamCount
plumbing are dead. Drop them and reword the affected comments.
The 124 concrete node classes that are neither a base of another node nor a
host for a generated PatternPlaceholder subclass are now sealed, so the JIT can
devirtualize the slot dispatch (GetChild, GetChildCount, GetChildSlotInfo,
GetChildNodes, AcceptVisitor) when the static type is the sealed leaf. Identifier's
constructor becomes private (protected is meaningless and an error in a sealed
type). Abstract bases, base classes (PreProcessorDirective, the EntityDeclaration/
AstType/Statement/Expression hierarchy roots), and pattern-placeholder hosts stay
open.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Scalar value properties that merely forwarded to a private backing field
(IsAsync, Operator and the operator-type enums, Format, ClassType, Variance,
ParameterModifier, the parameter bool flags, and similar) become
auto-properties, formatted on a single line. Behavior is identical;
PrimitiveExpression's constructor sets the property instead of the dropped
field.
Assisted-by: Claude:claude-opus-4-8:Claude Code
NodeType was NRefactory's coarse node category, but only three reads remained
here: two checks now expressed as "is not Trivia" and one debug assert for the
pattern category. Remove the enum, the abstract property, every per-node
override, and the generator's emission, preserving the pattern-placeholder case
through an IPatternPlaceholder marker interface the output-visitor assert
checks. Also remove the unused PrimitiveExpression.AdvanceLocation helper.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The grammar-production doc comments were transcribed in ANTLR style and
often copied the C# spec verbatim, including sub-rules the AST does not
model. Rewrite them as W3C EBNF (::=, ?, *, +), unroll sub-productions
that are not themselves AST nodes (e.g. anonymous_function_modifier ->
'async'), and shape each production to the node's actual members. Render
top-level alternations of node productions as multi-line <code> blocks;
keep operator and keyword token lists inline.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Each concrete syntax node now carries, in an XML-doc <remarks> block, the
matching production from the C# language specification grammar (ECMA/Microsoft,
ANTLR notation), quoted verbatim. Aggregate nodes (e.g. BinaryOperatorExpression,
ComposedType, TypeDeclaration) list every production they span; lexical/trivia
nodes (Comment, the preprocessor directives, Identifier) cite the lexical rule.
Nodes with no spec production -- ErrorExpression, UndocumentedExpression,
InvocationAstType, TypeReferenceExpression, NamedExpression, DocumentationReference,
and the C# 14 ExtensionDeclaration -- carry a hand-written EBNF plus a note
explaining why no official production exists.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The generator emits the IAstVisitor interface, the AcceptVisitor overloads,
and the null-node and pattern-placeholder nodes from [DecompilerAstNode]
declarations, so drop the hand-written equivalents across the C# AST: per-node
AcceptVisitor/DoMatch, the #region Null / #region PatternPlaceholder blocks,
IAstVisitor.cs, and now-dead usings. Also adds AccessorKind and moves
IdentifierExpressionBackreference into the PatternMatching folder.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Introduce a Roslyn source generator that emits the visitor boilerplate for
the C# AST from [DecompilerAstNode]-tagged node declarations: the
IAstVisitor interface, the AcceptVisitor overloads, the pattern-placeholder
nodes, and the initial DoMatch support. AccessorKind lets an accessor's
keyword be chosen independently of its role, an early step toward shedding
the NRefactory role model.
The C# AST inherited NRefactory's freezable model (IFreezable, Freeze,
IsFrozen, a frozen flag bit, and ThrowIfFrozen guards on every mutator),
but the decompiler never uses it: nothing calls Freeze(), not even the
generated null-node singletons, so every IsFrozen guard only ever
evaluated false. The decompiler is single-threaded and never shares or
freezes nodes. Remove the whole apparatus as preparation for the
slot-based AST rewrite, which has no place for it. Roles are untouched
here, so the flags word keeps its role index; only the freed frozen bit
goes away.
Siegfried Pammer
Peter Crabtree
Daniel Grunwald
dotnet format
Christoph Wille