use ra_syntax::{ ast::{self, AstNode, AstToken, NameOwner, TypeParamsOwner}, TextUnit, }; use stdx::{format_to, SepBy}; use crate::{Assist, AssistCtx, AssistId}; // Assist: add_impl // // Adds a new inherent impl for a type. // // ``` // struct Ctx { // data: T,<|> // } // ``` // -> // ``` // struct Ctx { // data: T, // } // // impl Ctx { // // } // ``` pub(crate) fn add_impl(ctx: AssistCtx) -> Option { let nominal = ctx.find_node_at_offset::()?; let name = nominal.name()?; ctx.add_assist(AssistId("add_impl"), format!("Implement {}", name.text().as_str()), |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 { format_to!(buf, "{}", type_params.syntax()); } 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()) .map(|it| it.text().clone()); let type_params = type_params.type_params().filter_map(|it| it.name()).map(|it| it.text().clone()); let generic_params = lifetime_params.chain(type_params).sep_by(", "); format_to!(buf, "<{}>", generic_params) } buf.push_str(" {\n"); edit.set_cursor(start_offset + TextUnit::of_str(&buf)); buf.push_str("\n}"); edit.insert(start_offset, buf); }) } #[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>> {}", ); } }