… arity

The error helper only accepts the two MATCH_CONDITION operands; drop the
unused left/right AttributeSet arguments from the throw site.

Rule.ruleId is a lazy val; overriding it with a non-lazy val fails
compilation. The base Rule implementation already derives the same id
from the class name, so drop the override entirely.

Wrap long lines and reorder expression imports so the braced import
precedes expressions.aggregate.

Store parsed MATCH_CONDITION operands in AsOfMatchCondition so mapExpressions
does not corrupt the tuple shape. Resolve operands in ResolveReferences and
materialize asOfCondition in ResolveAsOfJoin, including USING column projection.

…enabled

Default the new SQL syntax off while under development. AstBuilder rejects
ASOF JOIN at parse time when disabled; tests opt in via SQLConf.

…iance doc

SQLKeywordSuite requires new lexer keywords to be listed in
sql-ref-ansi-compliance.md with correct reserved/non-reserved status.

ASOF is a Spark extension, not SQL standard, so it belongs in
ansiNonReserved rather than being reserved under ANSI mode.

…sing

Restrict matchComparison to valueExpression so boolean AND is rejected at
parse time. Tighten type validation for incompatible operand pairs and
prepare struct/tuple ordering for field-wise distance expressions.

…expressions

Expose parsed MATCH_CONDITION operand trees to analysis pruning and
expression rewriting so functions, interval arithmetic, and ON predicates
all resolve before ResolveAsOfJoin materializes the join condition.

…erands

Recursively build min_by order expressions for nested structs (leaf
flattening) and arrays (ZipWith over element-wise diffs). Use signed
comparison distance for orderable non-numeric types like STRING. Add
AsOfJoinSQLSuite coverage for nested struct, ARRAY<INT>, and struct tuple
operands on the min_by rewrite path.

Regenerate keywords golden files to include ASOF and MATCH_CONDITION
from the lexer vocabulary. Update bitwise parse-error goldens after the
ASOF JOIN grammar change shifts the reported token for `> >>` syntax.

Add ASOF and MATCH_CONDITION to the SPARK-43119 hardcoded keyword list
returned by GetInfo(CLI_ODBC_KEYWORDS).

Reorder ASOF_JOIN_MATCH_CONDITION_* entries before ASSIGNMENT_ARITY_MISMATCH
and AS_OF_JOIN in error-conditions.json to satisfy SparkThrowableSuite
key ordering (ORDER_MAP_ENTRIES_BY_KEYS).

Add ASOF and MATCH_CONDITION to the hardcoded getSQLKeywords expectation
after the new ASOF JOIN grammar keywords were registered.

Parse MATCH_CONDITION comparisons as booleanExpression instead of a
dedicated matchComparison rule, which disturbed unrelated expression
error reporting (e.g. CHECK constraints). Move ASOF JOIN to a trailing
grammar alternative and validate allowed comparison operators in
AstBuilder. Update the join_ parse-error golden after the new ASOF
alternative changes ANTLR error recovery.

Revert the reported error token for `SELECT 20181117 > >> 2` back to
'>>' after removing the ASOF matchComparison grammar rule restored the
original ANTLR error recovery behavior.

Validate MATCH_CONDITION operands that reference both join inputs before
materializing the comparison, so invalid SQL like (t.col + r.col >= r.col)
raises ASOF_JOIN_MATCH_CONDITION_TABLE_REFERENCE instead of an internal
unresolved-operator error.