decide: nine constructs measuring short in a boolean slot

[dekobon]

Summary

Nine constructs measured short of an identifier control in a boolean slot
during the 2026-09-14 batch, each deliberately not fixed because counting
it is a judgement call rather than a clear omission. Collecting them so the
measurements are not lost; each needs a decision, not a sweep.

All measured with a rebuilt release binary against an identifier control at
the same cyclomatic, per #1458.

C# — four spellings, 0 conditions against 1 decision

source	notes
if (default(bool))	default_expression — a real bool terminal; the strongest candidate of the four
if (checked(b))	checked_expression — a transparent wrapper; arguably belongs in the peel, not the terminal set
if (b = C())	assignment_expression — the = counts on the A axis; whether the predicate also counts on C is the #1461 walrus question in C# form
if (new Wrapper())	object_creation_expression via a user-defined implicit bool conversion

A fifth, if (x switch { _ => true }), scores 0 only because its sole arm is
the excluded bare discard — that one is working as designed.

Non-literal shapes measuring short against sibling precedent

• JavaScript this — Kotlin lists ThisExpression in its terminal set;
  the JS family does not.
• Groovy object_creation_expression — JS has NewExpression and PHP
  has ObjectCreationExpression in theirs; Groovy does not.
• Groovy spread_dot_expression (a*.b) — a navigation form, but it
  yields a list whose Groovy truth is emptiness rather than the navigation,
  and no sibling language counts a spread. The closest call of the fifteen
  unlisted Groovy _expression alternatives.

Perl / Ruby / Elixir shapes outside the literal class

Found while extending the literal sweep; out of that class and undecided:
Perl s/// and tr/// (operations on $_ yielding a count),
anonymous_function, array_dereference (@$b scores 0 while @a scores
1 — arguably the clearest defect in this list); Ruby lambda and a range in
a predicate slot; Elixir anonymous_function and &f/1.

Also worth a look, unmeasured

Groovy::Identifier2 (141) was not observed emitted in any probe during the
batch. Either it is a hidden or unreachable variant — in which case §2 says
pin its unreachability — or it is reachable and unlisted.

How to take this

Do not land these as one sweep. Each is a policy call about what ABC's C
axis counts, and #1461 is the standing decision that governs the shape of the
answer: a relational operator scores by use, a value-bearing operand scores
in a boolean slot. Classify each construct against that rule first, then
measure the corpus cost of the ones that survive.

Related

• decide: four uncounted boolean operands, and whether terminal sets should be token arms #1461 — the by-use / by-slot rule these should be classified against.
• fix(abc): non-numeric truthy literals score no condition #1462, fix(abc/groovy): indexing and safe navigation score no condition #1466, fix(abc/csharp): the null-forgiving b! scores no condition #1463 — the sweeps that surfaced them.
• meta: sibling sweeps are asserted rather than measured #1458 — sibling sweeps asserted rather than measured.