Invariants that involve types (stack type of a variable against its IType,
the element type of an array access, the operand types of a comparison)
need a type system to resolve them against, and the only correct one is the
type system the instruction tree was decoded with. Until now CheckInvariant
took only the phase, so such a check had no compilation to use:
DeconstructInstruction.CheckInvariant called IsAssignment with a null type
system, which only held up because the targets it sees are ldloc, whose
InferType never touches the compilation; a ldflda-wrapped or pointer target
would have failed inside the invariant instead of reporting a violation.
Every call site already has that type system in scope: the ILReader's
compilation, the ILTransformContext of the running transform, or the
decompiler's own IDecompilerTypeSystem. It is now passed explicitly and the
base implementation asserts it is present, so a future invariant can rely
on it without re-plumbing the callers.
Assisted-by: Claude:claude-fable-5:Claude Code
The debug-step node bracket (MarkNodeStart/try/finally/MarkNodeEnd) was copied
into every hand-written WriteTo override and re-emitted by the T4 generator, so
a newly added instruction could silently omit it and lose step highlighting with
no compile error or test failure. Seal WriteTo on ILInstruction to apply the
bracket once and delegate to a new abstract WriteToCore; move every override
(hand-written and generated) to WriteToCore without the wrapper. Rendered output
is unchanged -- the marks are no-ops unless the output tracks nodes.
Assisted-by: Claude:claude-opus-4-8:Claude Code
The C# debug-steps view highlights and centers the exact AST node a
transform changed; the ILAst view already had the step tree and
replay-at-step but produced no highlight. Bring it to parity.
IL rendering has no token-writer seam like the C# output visitor, so
per-instruction text spans are recorded by bracketing
ILInstruction.WriteTo via a new INodeTrackingOutput. The dominant
inst.ReplaceWith(newInst) transform pattern detaches the instruction
passed to Step, so ILTransformContext gains EndStep to record the
produced instruction; Stepper additionally records the position's
ancestor chain as fallback candidates before the step-limit throw, so
the "show state before" view -- which halts at the selected step --
still resolves to a surviving ancestor (ultimately the ILFunction).
The highlight-range resolver is shared with the C# language.
Assisted-by: Claude:claude-opus-4-8:Claude Code
Siegfried Pammer
Peter Crabtree
Daniel Grunwald
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