use ra_syntax::{ algo::non_trivia_sibling, ast::{self, AstNode}, Direction, T, }; use crate::{Assist, AssistCtx, AssistId}; // Assist: flip_trait_bound // // Flips two trait bounds. // // ``` // fn foo Copy>() { } // ``` // -> // ``` // fn foo() { } // ``` pub(crate) fn flip_trait_bound(ctx: AssistCtx) -> Option { // We want to replicate the behavior of `flip_binexpr` by only suggesting // the assist when the cursor is on a `+` let plus = ctx.find_token_at_offset(T![+])?; // Make sure we're in a `TypeBoundList` if ast::TypeBoundList::cast(plus.parent()).is_none() { return None; } let (before, after) = ( non_trivia_sibling(plus.clone().into(), Direction::Prev)?, non_trivia_sibling(plus.clone().into(), Direction::Next)?, ); ctx.add_assist(AssistId("flip_trait_bound"), "Flip trait bounds", |edit| { edit.target(plus.text_range()); edit.replace(before.text_range(), after.to_string()); edit.replace(after.text_range(), before.to_string()); }) } #[cfg(test)] mod tests { use super::*; use crate::helpers::{check_assist, check_assist_not_applicable, check_assist_target}; #[test] fn flip_trait_bound_assist_available() { check_assist_target(flip_trait_bound, "struct S where T: A <|>+ B + C { }", "+") } #[test] fn flip_trait_bound_not_applicable_for_single_trait_bound() { check_assist_not_applicable(flip_trait_bound, "struct S where T: <|>A { }") } #[test] fn flip_trait_bound_works_for_struct() { check_assist( flip_trait_bound, "struct S where T: A <|>+ B { }", "struct S where T: B <|>+ A { }", ) } #[test] fn flip_trait_bound_works_for_trait_impl() { check_assist( flip_trait_bound, "impl X for S where T: A +<|> B { }", "impl X for S where T: B +<|> A { }", ) } #[test] fn flip_trait_bound_works_for_fn() { check_assist(flip_trait_bound, "fn f+ B>(t: T) { }", "fn f+ A>(t: T) { }") } #[test] fn flip_trait_bound_works_for_fn_where_clause() { check_assist( flip_trait_bound, "fn f(t: T) where T: A +<|> B { }", "fn f(t: T) where T: B +<|> A { }", ) } #[test] fn flip_trait_bound_works_for_lifetime() { check_assist( flip_trait_bound, "fn f(t: T) where T: A <|>+ 'static { }", "fn f(t: T) where T: 'static <|>+ A { }", ) } #[test] fn flip_trait_bound_works_for_complex_bounds() { check_assist( flip_trait_bound, "struct S where T: A <|>+ b_mod::B + C { }", "struct S where T: b_mod::B <|>+ A + C { }", ) } #[test] fn flip_trait_bound_works_for_long_bounds() { check_assist( flip_trait_bound, "struct S where T: A + B + C + D + E + F +<|> G + H + I + J { }", "struct S where T: A + B + C + D + E + G +<|> F + H + I + J { }", ) } }