Implement Eq alongside Hash

It turns out implementing Hash alone is not very useful, as
std::collection::HashMap keys are required to implement both Hash and
Eq.

Co-authored-by: Nikhil Benesch <nikhil.benesch@gmail.com>

src/ast/data_type.rs

@@ -13,7 +13,7 @@
 use super::ObjectName;
 
 /// SQL data types
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum DataType {
     /// Fixed-length character type e.g. CHAR(10)
     Char(Option<u64>),

src/ast/ddl.rs

@@ -3,7 +3,7 @@
 use super::{DataType, Expr, Ident, ObjectName};
 
 /// An `ALTER TABLE` (`SQLStatement::SQLAlterTable`) operation
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum AlterTableOperation {
     /// `ADD <table_constraint>`
     AddConstraint(TableConstraint),
@@ -22,7 +22,7 @@ impl ToString for AlterTableOperation {
 
 /// A table-level constraint, specified in a `CREATE TABLE` or an
 /// `ALTER TABLE ADD <constraint>` statement.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TableConstraint {
     /// `[ CONSTRAINT <name> ] { PRIMARY KEY | UNIQUE } (<columns>)`
     Unique {
@@ -81,7 +81,7 @@ impl ToString for TableConstraint {
 }
 
 /// SQL column definition
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct ColumnDef {
     pub name: Ident,
     pub data_type: DataType,
@@ -120,7 +120,7 @@ impl ToString for ColumnDef {
 /// For maximum flexibility, we don't distinguish between constraint and
 /// non-constraint options, lumping them all together under the umbrella of
 /// "column options," and we allow any column option to be named.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct ColumnOptionDef {
     pub name: Option<Ident>,
     pub option: ColumnOption,
@@ -138,7 +138,7 @@ impl ToString for ColumnOptionDef {
 
 /// `ColumnOption`s are modifiers that follow a column definition in a `CREATE
 /// TABLE` statement.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum ColumnOption {
     /// `NULL`
     Null,

src/ast/mod.rs

@@ -52,7 +52,7 @@ pub type Ident = String;
 /// The parser does not distinguish between expressions of different types
 /// (e.g. boolean vs string), so the caller must handle expressions of
 /// inappropriate type, like `WHERE 1` or `SELECT 1=1`, as necessary.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum Expr {
     /// Identifier e.g. table name or column name
     Identifier(Ident),
@@ -232,7 +232,7 @@ impl ToString for Expr {
 }
 
 /// A window specification (i.e. `OVER (PARTITION BY .. ORDER BY .. etc.)`)
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct WindowSpec {
     pub partition_by: Vec<Expr>,
     pub order_by: Vec<OrderByExpr>,
@@ -276,7 +276,7 @@ impl ToString for WindowSpec {
 
 /// Specifies the data processed by a window function, e.g.
 /// `RANGE UNBOUNDED PRECEDING` or `ROWS BETWEEN 5 PRECEDING AND CURRENT ROW`.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct WindowFrame {
     pub units: WindowFrameUnits,
     pub start_bound: WindowFrameBound,
@@ -285,7 +285,7 @@ pub struct WindowFrame {
     // TBD: EXCLUDE
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum WindowFrameUnits {
     Rows,
     Range,
@@ -318,7 +318,7 @@ impl FromStr for WindowFrameUnits {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum WindowFrameBound {
     /// "CURRENT ROW"
     CurrentRow,
@@ -343,7 +343,7 @@ impl ToString for WindowFrameBound {
 
 /// A top-level statement (SELECT, INSERT, CREATE, etc.)
 #[allow(clippy::large_enum_variant)]
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum Statement {
     /// SELECT
     Query(Box<Query>),
@@ -588,7 +588,7 @@ impl ToString for Statement {
 }
 
 /// A name of a table, view, custom type, etc., possibly multi-part, i.e. db.schema.obj
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct ObjectName(pub Vec<Ident>);
 
 impl ToString for ObjectName {
@@ -598,7 +598,7 @@ impl ToString for ObjectName {
 }
 
 /// SQL assignment `foo = expr` as used in SQLUpdate
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Assignment {
     pub id: Ident,
     pub value: Expr,
@@ -611,7 +611,7 @@ impl ToString for Assignment {
 }
 
 /// SQL function
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Function {
     pub name: ObjectName,
     pub args: Vec<Expr>,
@@ -636,7 +636,7 @@ impl ToString for Function {
 }
 
 /// External table's available file format
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum FileFormat {
     TEXTFILE,
     SEQUENCEFILE,
@@ -685,7 +685,7 @@ impl FromStr for FileFormat {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum ObjectType {
     Table,
     View,
@@ -700,7 +700,7 @@ impl ObjectType {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct SqlOption {
     pub name: Ident,
     pub value: Value,
@@ -712,7 +712,7 @@ impl ToString for SqlOption {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TransactionMode {
     AccessMode(TransactionAccessMode),
     IsolationLevel(TransactionIsolationLevel),
@@ -728,7 +728,7 @@ impl ToString for TransactionMode {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TransactionAccessMode {
     ReadOnly,
     ReadWrite,
@@ -744,7 +744,7 @@ impl ToString for TransactionAccessMode {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TransactionIsolationLevel {
     ReadUncommitted,
     ReadCommitted,

src/ast/operator.rs

@@ -11,7 +11,7 @@
 // limitations under the License.
 
 /// Unary operators
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum UnaryOperator {
     Plus,
     Minus,
@@ -29,7 +29,7 @@ impl ToString for UnaryOperator {
 }
 
 /// Binary operators
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum BinaryOperator {
     Plus,
     Minus,

src/ast/query.rs

@@ -14,7 +14,7 @@ use super::*;
 
 /// The most complete variant of a `SELECT` query expression, optionally
 /// including `WITH`, `UNION` / other set operations, and `ORDER BY`.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Query {
     /// WITH (common table expressions, or CTEs)
     pub ctes: Vec<Cte>,
@@ -56,7 +56,7 @@ impl ToString for Query {
 
 /// A node in a tree, representing a "query body" expression, roughly:
 /// `SELECT ... [ {UNION|EXCEPT|INTERSECT} SELECT ...]`
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum SetExpr {
     /// Restricted SELECT .. FROM .. HAVING (no ORDER BY or set operations)
     Select(Box<Select>),
@@ -99,7 +99,7 @@ impl ToString for SetExpr {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum SetOperator {
     Union,
     Except,
@@ -119,7 +119,7 @@ impl ToString for SetOperator {
 /// A restricted variant of `SELECT` (without CTEs/`ORDER BY`), which may
 /// appear either as the only body item of an `SQLQuery`, or as an operand
 /// to a set operation like `UNION`.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Select {
     pub distinct: bool,
     /// projection expressions
@@ -161,7 +161,7 @@ impl ToString for Select {
 /// The names in the column list before `AS`, when specified, replace the names
 /// of the columns returned by the query. The parser does not validate that the
 /// number of columns in the query matches the number of columns in the query.
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Cte {
     pub alias: TableAlias,
     pub query: Query,
@@ -174,7 +174,7 @@ impl ToString for Cte {
 }
 
 /// One item of the comma-separated list following `SELECT`
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum SelectItem {
     /// Any expression, not followed by `[ AS ] alias`
     UnnamedExpr(Expr),
@@ -199,7 +199,7 @@ impl ToString for SelectItem {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct TableWithJoins {
     pub relation: TableFactor,
     pub joins: Vec<Join>,
@@ -216,7 +216,7 @@ impl ToString for TableWithJoins {
 }
 
 /// A table name or a parenthesized subquery with an optional alias
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum TableFactor {
     Table {
         name: ObjectName,
@@ -283,7 +283,7 @@ impl ToString for TableFactor {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct TableAlias {
     pub name: Ident,
     pub columns: Vec<Ident>,
@@ -299,7 +299,7 @@ impl ToString for TableAlias {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Join {
     pub relation: TableFactor,
     pub join_operator: JoinOperator,
@@ -352,7 +352,7 @@ impl ToString for Join {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum JoinOperator {
     Inner(JoinConstraint),
     LeftOuter(JoinConstraint),
@@ -365,7 +365,7 @@ pub enum JoinOperator {
     OuterApply,
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum JoinConstraint {
     On(Expr),
     Using(Vec<Ident>),
@@ -373,7 +373,7 @@ pub enum JoinConstraint {
 }
 
 /// SQL ORDER BY expression
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct OrderByExpr {
     pub expr: Expr,
     pub asc: Option<bool>,
@@ -389,7 +389,7 @@ impl ToString for OrderByExpr {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Fetch {
     pub with_ties: bool,
     pub percent: bool,
@@ -413,7 +413,7 @@ impl ToString for Fetch {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Values(pub Vec<Vec<Expr>>);
 
 impl ToString for Values {

src/ast/value.rs

@@ -13,7 +13,7 @@
 use ordered_float::OrderedFloat;
 
 /// Primitive SQL values such as number and string
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum Value {
     /// Unsigned integer value
     Long(u64),
@@ -113,7 +113,7 @@ impl ToString for Value {
     }
 }
 
-#[derive(Debug, Clone, PartialEq, Hash)]
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum DateTimeField {
     Year,
     Month,