fix: drop unused splitSQLStatements shim and unify ArrayConstructor cleanup

- Remove the unused splitSQLStatements shim from pkg/gosqlx/reader.go;
  golangci-lint's `unused` checker flagged it because golangci.yml runs
  with `tests: false`. The single test caller now uses SplitStatements
  directly with the explicit ANSI dialect.
- Route ArrayConstructorExpression.Subquery through releaseStatement
  (matching In/Subquery/Exists/Any/All) instead of the type-specific
  PutSelectStatement helper, so non-SELECT statement subqueries dispatch
  through the shared cleanup path.

Author: claude

pkg/gosqlx/reader.go

@@ -222,10 +222,3 @@ func (c *ctxReader) Read(p []byte) (int, error) {
 	return c.r.Read(p)
 }
 
-// splitSQLStatements is retained as a thin shim over SplitStatements so
-// existing tests and internal callers that use the ANSI default keep working
-// unchanged. New code should call SplitStatements directly with an explicit
-// dialect.
-func splitSQLStatements(src string) []string {
-	return SplitStatements(src, "")
-}

pkg/gosqlx/reader_test.go

@@ -292,7 +292,7 @@ func TestSplitSQLStatements(t *testing.T) {
 	}
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
-			segs := splitSQLStatements(tc.in)
+			segs := SplitStatements(tc.in, "")
 			count := 0
 			for _, s := range segs {
 				if strings.TrimSpace(s) != "" {

pkg/sql/ast/pool_expression_release.go

@@ -438,10 +438,12 @@ func putExpressionImpl(expr Expression, depth int) {
 				e.Elements[i] = nil
 			}
 			e.Elements = e.Elements[:0]
-			// Subquery is *SelectStatement — release through the
-			// statement pool, not a bare nil-assign (leak before fix).
+			// Subquery is a Statement (typically *SelectStatement); route
+			// through the statement dispatcher to keep dispatch consistent
+			// with InExpression / SubqueryExpression / Exists / Any / All
+			// and to handle non-SELECT statement types correctly.
 			if e.Subquery != nil {
-				PutSelectStatement(e.Subquery)
+				releaseStatement(e.Subquery)
 				e.Subquery = nil
 			}
 			arrayConstructorPool.Put(e)
@@ -656,9 +658,10 @@ func PutArrayConstructor(ac *ArrayConstructorExpression) {
 		ac.Elements[i] = nil
 	}
 	ac.Elements = ac.Elements[:0]
-	// Subquery is *SelectStatement — release through the statement pool.
+	// Subquery is a Statement; route through releaseStatement so non-SELECT
+	// statement types (sequence ops etc.) dispatch correctly.
 	if ac.Subquery != nil {
-		PutSelectStatement(ac.Subquery)
+		releaseStatement(ac.Subquery)
 		ac.Subquery = nil
 	}
 	arrayConstructorPool.Put(ac)