From 3b0903f8eb453ae75b6660af70cf02df6db56431 Mon Sep 17 00:00:00 2001
From: Orson Peters <orsonpeters@gmail.com>
Date: Wed, 18 Sep 2024 11:31:40 +0200
Subject: [PATCH] refactor(rust): Add missing implicit datetime alias in ExprIR

---
 .../polars-plan/src/dsl/functions/temporal.rs | 32 +++++++++++--------
 1 file changed, 18 insertions(+), 14 deletions(-)

diff --git a/crates/polars-plan/src/dsl/functions/temporal.rs b/crates/polars-plan/src/dsl/functions/temporal.rs
index 145b521092d3..48508dba40d8 100644
--- a/crates/polars-plan/src/dsl/functions/temporal.rs
+++ b/crates/polars-plan/src/dsl/functions/temporal.rs
@@ -208,21 +208,25 @@ pub fn datetime(args: DatetimeArgs) -> Expr {
         ambiguous,
     ];
 
-    Expr::Function {
-        input,
-        function: FunctionExpr::TemporalExpr(TemporalFunction::DatetimeFunction {
-            time_unit,
-            time_zone,
+    Expr::Alias(
+        Arc::new(Expr::Function {
+            input,
+            function: FunctionExpr::TemporalExpr(TemporalFunction::DatetimeFunction {
+                time_unit,
+                time_zone,
+            }),
+            options: FunctionOptions {
+                collect_groups: ApplyOptions::ElementWise,
+                flags: FunctionFlags::default()
+                    | FunctionFlags::INPUT_WILDCARD_EXPANSION
+                    | FunctionFlags::ALLOW_RENAME,
+                fmt_str: "datetime",
+                ..Default::default()
+            },
         }),
-        options: FunctionOptions {
-            collect_groups: ApplyOptions::ElementWise,
-            flags: FunctionFlags::default()
-                | FunctionFlags::INPUT_WILDCARD_EXPANSION
-                | FunctionFlags::ALLOW_RENAME,
-            fmt_str: "datetime",
-            ..Default::default()
-        },
-    }
+        // TODO: follow left-hand rule in Polars 2.0.
+        PlSmallStr::from_static("datetime"),
+    )
 }
 
 /// Arguments used by `duration` in order to produce an [`Expr`] of [`Duration`]