revert sql_interval_expr refactor

Author: kosiew

datafusion/sql/src/expr/mod.rs

@@ -233,7 +233,7 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
             }
 
             SQLExpr::Array(arr) => self.sql_array_literal(arr.elem, schema),
-            SQLExpr::Interval(interval) => Self::sql_interval_to_expr(false, interval),
+            SQLExpr::Interval(interval) => self.sql_interval_to_expr(false, interval),
             SQLExpr::Identifier(id) => {
                 self.sql_identifier_to_expr(id, schema, planner_context)
             }

datafusion/sql/src/expr/unary_op.rs

@@ -69,7 +69,7 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
                         span: _,
                     }) => self.parse_sql_number(&n, true),
                     SQLExpr::Interval(interval) => {
-                        Self::sql_interval_to_expr(true, interval)
+                        self.sql_interval_to_expr(true, interval)
                     }
                     // Not a literal, apply negative operator on expression
                     _ => Ok(Expr::Negative(Box::new(self.sql_expr_to_logical_expr(

datafusion/sql/src/expr/value.rs

@@ -187,6 +187,7 @@ impl<S: ContextProvider> SqlToRel<'_, S> {
     /// Convert a SQL interval expression to a DataFusion logical plan
     /// expression
     pub(super) fn sql_interval_to_expr(
+        &self,
         negative: bool,
         interval: Interval,
     ) -> Result<Expr> {