This commit also changes the ILAst representation of with-initializers to preserve the `<Clone>$()` call, so that BlockKind.WithInitializer only forces the block into a certain shape, without assigning its special semantics.
When an IfInstruction was created with resultType=bool, because only
values 0 or 1 are possible, then we need to preserve this property in
transforms -- otherwise the added correctness test would fail.
The block addresses its allocation through the pointer localloc returns, and
only its result is a Span<T>. Retyping the initializer variable to the span
made every element store ask for a pointer it no longer had, which was papered
over with a conv from the span; once Obj and VT became distinct stack types
that conv had no conversion kind left and the whole method failed to decompile.
The span constructor becomes the block's final instruction instead, so the
element stores keep the pointer they were written against and the block still
evaluates to the span.
Assisted-by: Claude:claude-opus-5[1m]:Claude Code
Change InferType() to an abstract method and implement for every ILInstruction.
With this change, we now always have enough information to create a variable of an appropriate type to store the result of evaluating the instruction.
This previously was not the case for instructions producing "other value type", for which the stacktype-based fallback incorrectly produced `object`.
C# has no ref-returning switch expression. Skip the transform for StackType.Ref and cover the statement form in RefLocalsAndReturns.
Co-authored-by: Copilot <[email protected]>
Copilot-Session: 0dd407b6-9410-48df-add5-761ca4a8dec0
DynamicIsEventInstruction has no ExpressionBuilder visitor, so any is-event
diamond that survives the transform pipeline leaks as an "OpCode not supported"
comment. The collapse only fired for the plain statement form; every other
lowering the compiler emits for "d.Event += b" was missed:
- a copy-of-value temporary between the getmember cache and the diamond (modern
Roslyn emits it for the statement form),
- the result-used shape, where the diamond is a value-if nested inside the
consuming expression (a call argument, or a leave's value when returned),
- the result-returned shape as two leaves, "if (isevent) leave(add)" plus a
fall-through "leave(compound)" rather than an if/else, and
- the same two-leaves shape when the optimizer drops the getmember cache (legacy
csc and Roslyn <= 2.x): the is-event flag then feeds a single branch, inlining
folds it into the condition, and the compound leave is already collapsed, so
the cache-based entry never matched it and the branch leaked. These compilers
only run on Windows CI, so the gap was invisible on Linux.
The descendants walk handles the nested value-if once an over-strict
copy-of-value bounds guard (which never held for the compact return block) is
dropped. The two two-leaves shapes share a skeleton matcher and the add/remove
accessor-name check, and both validate the accessor name and arguments. Re-running
from the collapsed statement instead of the next one avoids indexing past the end
of a block that has shrunk to a single leave.
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
Daniel Grunwald