Discovered by: /uber-report 2026-05-10 (SqlBuildingBlocks Architect)

Context

SelectReferenceResolver (706 lines) now handles eight responsibilities. The CTE pre-pass (ResolveCtes, RewriteCteReferences, WrapCteTable, ResolveNonRecursiveSetOperationTerms, ResolveRecursiveTerms) is ~200 lines substantially independent of the column-reference logic — they share only the read-only constructor parameters.

Both classes are internal, so this is not a NuGet surface concern.

Proposed Work

Extract CTE resolution to internal class CteReferenceResolver in src/Core/Utils/CteReferenceResolver.cs. SelectReferenceResolver.ResolveTablesDatabase calls new CteReferenceResolver(...).Resolve(sqlSelectDefinition, outerTablesInScope) at its head and receives back the populated outerTablesInScope (CTEs added) before proceeding to column resolution.

Acceptance Criteria

• All 1279 existing tests pass without change
• SelectReferenceResolver is under 550 lines
• CteReferenceResolver is under 250 lines
• Both classes remain internal
• CTE resolution integration tests in AnsiSqlScenarioTests.cs pass