Implement Eq trait for Expr and nest types (apache#3381)

Author: jdye64

datafusion/expr/src/expr.rs

@@ -80,7 +80,7 @@ use std::sync::Arc;
 ///   assert_eq!(op, Operator::Eq);
 /// }
 /// ```
-#[derive(Clone, PartialEq, Hash)]
+#[derive(Clone, PartialEq, Eq, Hash)]
 pub enum Expr {
     /// An expression with a specific name.
     Alias(Box<Expr>, String),

datafusion/expr/src/udaf.rs

@@ -56,6 +56,8 @@ impl PartialEq for AggregateUDF {
     }
 }
 
+impl Eq for AggregateUDF {}
+
 impl std::hash::Hash for AggregateUDF {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         self.name.hash(state);

datafusion/expr/src/udf.rs

@@ -59,6 +59,8 @@ impl PartialEq for ScalarUDF {
     }
 }
 
+impl Eq for ScalarUDF {}
+
 impl std::hash::Hash for ScalarUDF {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         self.name.hash(state);

datafusion/expr/src/udtf.rs

@@ -52,6 +52,8 @@ impl PartialEq for TableUDF {
     }
 }
 
+impl Eq for TableUDF {}
+
 impl std::hash::Hash for TableUDF {
     fn hash<H: std::hash::Hasher>(&self, state: &mut H) {
         self.name.hash(state);