claude@clouddev1
3912fb5a9b
Expression WARNING diagnostics (type mismatch, = NULL) carried a coarse span — the whole WHERE clause, from the `where` keyword to end of input. They now span exactly the offending literal operand, read from the Operand source span added in the previous commit. predicate_warnings derives the span per warning; pair_type_mismatch returns (message, literal-span); the dead where_clause_span helper is removed. 5 walker tests assert the spans cover exactly the literal / identifier (type mismatch, = NULL, BETWEEN bounds, IN item, unknown-column ERROR). 1105 passing, clippy clean.