[CaffeinatedCoder]

Closes #375
Closes #376
Closes #377
Closes #378
Closes #379
Closes #380

Problem

The differential sweeps vary shapes, types and operand kinds, mostly in a projection and over one nullable column at most. #349, #350, #355, #360 and #361 all came from how a translated call composes inside a query: where the NULL comes from, what EF Core's null semantics do around it, and what a later execution reuses. Nothing swept that axis (#362).

Change

Six sweeps in the integration project, each in a database of its own, over DateRange, its RangeSet and StringSet, with the members discovered (Composition/CompositionMembers.cs):

Class	Issue	What it composes
OuterJoinProbeTests	#375	every member over the child of a parent without one (navigation, GroupJoin + DefaultIfEmpty, LeftJoin), the factories over the child's element columns, bounds through ??
NullableOperandPairProbeTests	#376	every binary member over two nullable columns, a CASE and a COALESCE, on every (null, value) pair; equality and CompareTo under their documented rules
QuantifierProbeTests	#377	Any/All/Count/Contains over captured lists holding NULL; P && Q, P || Q with De Morgan; predicates over value-producing members
RepeatedExecutionProbeTests	#378	one query re-run with its parameter walked null → finite → empty → (,) → null and back, lists walked empty → one → duplicate → NULL; EF.CompileQuery/EF.CompileAsyncQuery
FilteredAggregateProbeTests	#379	RangeAgg/RangeIntersectAgg over groups that are filtered empty, all NULL, hold empty, or are a LeftJoin key without rows, consumed by every member, HAVING, HAVING NOT and an ordering by a bound
DeclaredNullabilityTests	#380	every function the translators emit against pg_proc.proisstrict and the server (typed NULLs, empty, (,), {}); every translated value's null test against its projection

The reference is Composition/NullRule.cs: the expression rewritten so a NULL never reaches the library (rule (c) for a predicate, no value for a value-producing member or a missing element, equality and CompareTo under their own documented rules, aggregates skipping NULL). Documented differences are mapped, not reported: E07 (aggregates over zero inputs), E72 (ordering by a bound), CompareTo (#261). CompositionRunner adds a reference-free check to every call: Where(P) and Where(!P) partition the rows and Select(P) says which side each row is on.

Registered in test/oracles/oracles.json, named in the heldBy of E07, E70, E71 and E72, with the axes in test/oracles/axes.md and a section in docs/oracles.md. No change to src/.

What they found

Every disagreement is a filed issue and a candidates.json entry:

• Contains(element) on a range or RangeSet is NULL in SQL for a NULL element: the negation drops the row EF Core keeps, and a projection into bool throws #381 (new, silent, low): Contains(element) on a range or RangeSet with a NULL element (outer join, nullable element column) is NULL in SQL, so the negation drops the row EF Core keeps, a projection into bool throws, and under All a positive filter selects the row.
• The range factories over a NULL element build a range: CreateFinite gives empty and CreateUnboundedStart/End give (,), where EF Core answers NULL #382 (new, silent, medium): the factories over a NULL element build a range (CreateFinite → empty, CreateUnboundedStart/End → (,)), so CreateUnboundedEnd(c.From).Contains(v) selects a parent without a child.
• Value set Union is declared NULL only for a NULL operand, but array_cat isn't strict: a filter and a projection disagree on a NULL column #360 (existing): array_cat and array_remove are declared strict and are not; reached through an outer join, two nullable columns, a NULL parameter and a nullable element. Measured in a comment there.

Clean: predicates, bounds and range/multirange value operations over a missing child; two nullable operands including CASE/COALESCE; equality and CompareTo; quantifiers over lists holding NULL (apart from #381's All); 112 compound predicates with De Morgan; nested predicates; repeated and compiled execution (apart from #360); every aggregate consumption; every other emitted function's declaration.

Tests

• All six classes pass on PostgreSQL 16 and 18 with their candidates (floors: judged calls per sweep).
• Seeds, dotnet run tools/oracles.cs seeds, each CAUGHT by the sweeps it names:
  • range-predicate-over-a-null-column-is-null, value-set-predicate-over-a-null-column-is-null: sweeps 1–4;
  • bound-declared-null-only-for-a-null-argument (fix: declare lower() and upper() NULL for a non-null range #353 reverted): sweeps 1, 2, 5, 6;
  • aggregates-fold-a-null-input: sweep 5;
  • new sql-processor-reuses-its-first-output: sweep 4 (no other sweep re-executes a query shape with another parameter);
  • new range-agg-declared-never-null: sweep 5.
• Conventions project green (seeds, candidates, claims, catalogue).

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