execution: add forgotten subquery guards (#369)

Signed-off-by: Michael Hoffmann <[email protected]>

Author: MichaHoffmann

execution/execution.go

@@ -168,6 +168,9 @@ func newCall(e *parser.Call, storage *engstore.SelectorPool, opts *query.Options
 	for i := range e.Args {
 		switch t := e.Args[i].(type) {
 		case *parser.SubqueryExpr:
+			if !opts.IsInstantQuery() {
+				return nil, parse.ErrNotImplemented
+			}
 			if !opts.EnableSubqueries {
 				return nil, parse.ErrNotImplemented
 			}
@@ -182,6 +185,12 @@ func newCall(e *parser.Call, storage *engstore.SelectorPool, opts *query.Options
 func newAbsentOverTimeOperator(call *parser.Call, storage *engstore.SelectorPool, opts *query.Options, hints storage.SelectHints) (model.VectorOperator, error) {
 	switch arg := call.Args[0].(type) {
 	case *parser.SubqueryExpr:
+		if !opts.IsInstantQuery() {
+			return nil, parse.ErrNotImplemented
+		}
+		if !opts.EnableSubqueries {
+			return nil, parse.ErrNotImplemented
+		}
 		matrixCall := &parser.Call{
 			Func: &parser.Function{Name: "last_over_time"},
 		}