rust/crates/ra_assists/src/handlers/generate_impl.rs
2020-07-03 19:32:18 +02:00

110 lines
3.1 KiB
Rust

use ra_syntax::ast::{self, AstNode, NameOwner, TypeParamsOwner};
use stdx::{format_to, SepBy};
use crate::{AssistContext, AssistId, AssistKind, Assists};
// Assist: generate_impl
//
// Adds a new inherent impl for a type.
//
// ```
// struct Ctx<T: Clone> {
// data: T,<|>
// }
// ```
// ->
// ```
// struct Ctx<T: Clone> {
// data: T,
// }
//
// impl<T: Clone> Ctx<T> {
// $0
// }
// ```
pub(crate) fn generate_impl(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let nominal = ctx.find_node_at_offset::<ast::NominalDef>()?;
let name = nominal.name()?;
let target = nominal.syntax().text_range();
acc.add(
AssistId("generate_impl", AssistKind::Generate),
format!("Generate impl for `{}`", name),
target,
|edit| {
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_token())
.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)
}
match ctx.config.snippet_cap {
Some(cap) => {
buf.push_str(" {\n $0\n}");
edit.insert_snippet(cap, start_offset, buf);
}
None => {
buf.push_str(" {\n}");
edit.insert(start_offset, buf);
}
}
},
)
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_target};
use super::*;
#[test]
fn test_add_impl() {
check_assist(
generate_impl,
"struct Foo {<|>}\n",
"struct Foo {}\n\nimpl Foo {\n $0\n}\n",
);
check_assist(
generate_impl,
"struct Foo<T: Clone> {<|>}",
"struct Foo<T: Clone> {}\n\nimpl<T: Clone> Foo<T> {\n $0\n}",
);
check_assist(
generate_impl,
"struct Foo<'a, T: Foo<'a>> {<|>}",
"struct Foo<'a, T: Foo<'a>> {}\n\nimpl<'a, T: Foo<'a>> Foo<'a, T> {\n $0\n}",
);
}
#[test]
fn add_impl_target() {
check_assist_target(
generate_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>> {}",
);
}
}