chore: remove deprecated expr in proto (#7190)

was not used after #411

Approved-By: lmatz

proto/expr.proto

@@ -110,9 +110,9 @@ message ExprNode {
     ARRAY_CAT = 531;
     ARRAY_APPEND = 532;
     ARRAY_PREPEND = 533;
-    // Search operator and Search ARGument
-    SEARCH = 998;
-    SARG = 999;
+
+    // Non-pure functions below (> 600)
+    // ------------------------
     // Internal functions
     VNODE = 1101;
     // Non-deterministic functions

src/frontend/src/expr/function_call.rs

@@ -208,8 +208,8 @@ impl FunctionCall {
         self.func_type
     }
 
+    /// Refer to [`ExprType`] for details.
     pub fn is_pure(&self) -> bool {
-        // See proto for details
         0 < self.func_type as i32 && self.func_type as i32 <= 600
     }
 

src/frontend/src/expr/mod.rs

@@ -41,23 +41,21 @@ mod utils;
 
 pub use agg_call::AggCall;
 pub use correlated_input_ref::{CorrelatedId, CorrelatedInputRef, Depth};
+pub use expr_mutator::ExprMutator;
+pub use expr_rewriter::ExprRewriter;
+pub use expr_visitor::ExprVisitor;
 pub use function_call::{is_row_function, FunctionCall, FunctionCallDisplay};
 pub use input_ref::{input_ref_to_column_indices, InputRef, InputRefDisplay};
 pub use literal::Literal;
+pub use risingwave_pb::expr::expr_node::Type as ExprType;
 pub use subquery::{Subquery, SubqueryKind};
 pub use table_function::{TableFunction, TableFunctionType};
-pub use window_function::{WindowFunction, WindowFunctionType};
-
-pub type ExprType = risingwave_pb::expr::expr_node::Type;
-
-pub use expr_mutator::ExprMutator;
-pub use expr_rewriter::ExprRewriter;
-pub use expr_visitor::ExprVisitor;
 pub use type_inference::{
     agg_func_sigs, align_types, cast_map_array, cast_ok, cast_sigs, func_sigs, infer_type,
     least_restrictive, AggFuncSig, CastContext, CastSig, FuncSign,
 };
 pub use utils::*;
+pub use window_function::{WindowFunction, WindowFunctionType};
 
 /// the trait of bound expressions
 pub trait Expr: Into<ExprImpl> {