use std::fmt::Write; use hir::db::HirDatabase; use join_to_string::join; use ra_syntax::{ ast::{self, AstNode, NameOwner, TypeParamsOwner}, TextUnit, }; use crate::{Assist, AssistCtx, AssistId}; pub(crate) fn add_impl(mut ctx: AssistCtx) -> Option { let nominal = ctx.node_at_offset::()?; let name = nominal.name()?; ctx.add_action(AssistId("add_impl"), "add impl", |edit| { edit.target(nominal.syntax().text_range()); let type_params = nominal.type_param_list(); let start_offset = nominal.syntax().text_range().end(); let mut buf = String::new(); buf.push_str("\n\nimpl"); if let Some(type_params) = &type_params { write!(buf, "{}", type_params.syntax()).unwrap(); } buf.push_str(" "); buf.push_str(name.text().as_str()); if let Some(type_params) = type_params { let lifetime_params = type_params .lifetime_params() .filter_map(|it| it.lifetime_token()) .map(|it| it.text().clone()); let type_params = type_params.type_params().filter_map(|it| it.name()).map(|it| it.text().clone()); join(lifetime_params.chain(type_params)).surround_with("<", ">").to_buf(&mut buf); } buf.push_str(" {\n"); edit.set_cursor(start_offset + TextUnit::of_str(&buf)); buf.push_str("\n}"); edit.insert(start_offset, buf); }); ctx.build() } #[cfg(test)] mod tests { use super::*; use crate::helpers::{check_assist, check_assist_target}; #[test] fn test_add_impl() { check_assist(add_impl, "struct Foo {<|>}\n", "struct Foo {}\n\nimpl Foo {\n<|>\n}\n"); check_assist( add_impl, "struct Foo {<|>}", "struct Foo {}\n\nimpl Foo {\n<|>\n}", ); check_assist( add_impl, "struct Foo<'a, T: Foo<'a>> {<|>}", "struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n<|>\n}", ); } #[test] fn add_impl_target() { check_assist_target( add_impl, " struct SomeThingIrrelevant; /// Has a lifetime parameter struct Foo<'a, T: Foo<'a>> {<|>} struct EvenMoreIrrelevant; ", "/// Has a lifetime parameter struct Foo<'a, T: Foo<'a>> {}", ); } }