--- /dev/null
+use hir::db::HirDatabase;
+use ra_syntax::{
+ ast::{AstNode, BinExpr, BinOp}
+};
+
+use crate::{AssistCtx, Assist, AssistId};
+
+pub(crate) fn flip_eq_operands(mut ctx: AssistCtx<impl HirDatabase>) -> Option<Assist> {
+ let expr = ctx.node_at_offset::<BinExpr>()?;
+ let allowed_ops = [BinOp::EqualityTest, BinOp::NegatedEqualityTest];
+ let expr_op = expr.op()?;
+ if ! allowed_ops.iter().any(|o| *o == expr_op) {
+ return None;
+ }
+ let node = expr.syntax();
+ let prev = node.first_child()?;
+ let next = node.last_child()?;
+ ctx.add_action(AssistId("flip_eq_operands"), "flip equality operands", |edit| {
+ edit.target(node.range());
+ edit.replace(prev.range(), next.text());
+ edit.replace(next.range(), prev.text());
+ });
+
+ ctx.build()
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ use crate::helpers::{check_assist, check_assist_target};
+
+ #[test]
+ fn flip_eq_operands_for_simple_stmt() {
+ check_assist(
+ flip_eq_operands,
+ "fn f() { let res = 1 ==<|> 2; }",
+ "fn f() { let res = 2 ==<|> 1; }",
+ )
+ }
+
+ #[test]
+ fn flip_neq_operands_for_simple_stmt() {
+ check_assist(
+ flip_eq_operands,
+ "fn f() { let res = 1 !=<|> 2; }",
+ "fn f() { let res = 2 !=<|> 1; }",
+ )
+ }
+
+ #[test]
+ fn flip_eq_operands_for_complex_stmt() {
+ check_assist(
+ flip_eq_operands,
+ "fn f() { let res = (1 + 1) ==<|> (2 + 2); }",
+ "fn f() { let res = (2 + 2) ==<|> (1 + 1); }",
+ )
+ }
+
+ #[test]
+ fn flip_eq_operands_in_match_expr() {
+ check_assist(
+ flip_eq_operands,
+ r#"
+ fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
+ match other.downcast_ref::<Self>() {
+ None => false,
+ Some(it) => it ==<|> self,
+ }
+ }
+ "#,
+ r#"
+ fn dyn_eq(&self, other: &dyn Diagnostic) -> bool {
+ match other.downcast_ref::<Self>() {
+ None => false,
+ Some(it) => self ==<|> it,
+ }
+ }
+ "#,
+ )
+ }
+
+ #[test]
+ fn flip_eq_operands_target() {
+ check_assist_target(flip_eq_operands, "fn f() { let res = 1 ==<|> 2; }", "1 == 2")
+ }
+}
mod add_derive;
mod add_impl;
mod flip_comma;
+mod flip_eq_operands;
mod change_visibility;
mod fill_match_arms;
mod fill_struct_fields;
fill_match_arms::fill_match_arms,
fill_struct_fields::fill_struct_fields,
flip_comma::flip_comma,
+ flip_eq_operands::flip_eq_operands,
introduce_variable::introduce_variable,
replace_if_let_with_match::replace_if_let_with_match,
split_import::split_import,