rust/crates/ide_assists/src/handlers/introduce_named_generic.rs
2021-09-21 00:54:09 +02:00

145 lines
3.6 KiB
Rust

use syntax::{
ast::{self, edit_in_place::GenericParamsOwnerEdit, make, AstNode},
ted,
};
use crate::{utils::suggest_name, AssistContext, AssistId, AssistKind, Assists};
// Assist: introduce_named_generic
//
// Replaces `impl Trait` function argument with the named generic.
//
// ```
// fn foo(bar: $0impl Bar) {}
// ```
// ->
// ```
// fn foo<B: Bar>(bar: B) {}
// ```
pub(crate) fn introduce_named_generic(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let impl_trait_type = ctx.find_node_at_offset::<ast::ImplTraitType>()?;
let param = impl_trait_type.syntax().parent().and_then(ast::Param::cast)?;
let fn_ = param.syntax().ancestors().find_map(ast::Fn::cast)?;
let type_bound_list = impl_trait_type.type_bound_list()?;
let target = fn_.syntax().text_range();
acc.add(
AssistId("introduce_named_generic", AssistKind::RefactorRewrite),
"Replace impl trait with generic",
target,
|edit| {
let impl_trait_type = edit.make_mut(impl_trait_type);
let fn_ = edit.make_mut(fn_);
let type_param_name = suggest_name::for_generic_parameter(&impl_trait_type);
let type_param = make::type_param(make::name(&type_param_name), Some(type_bound_list))
.clone_for_update();
let new_ty = make::ty(&type_param_name).clone_for_update();
ted::replace(impl_trait_type.syntax(), new_ty.syntax());
fn_.get_or_create_generic_param_list().add_generic_param(type_param.into())
},
)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tests::check_assist;
#[test]
fn introduce_named_generic_params() {
check_assist(
introduce_named_generic,
r#"fn foo<G>(bar: $0impl Bar) {}"#,
r#"fn foo<G, B: Bar>(bar: B) {}"#,
);
}
#[test]
fn replace_impl_trait_without_generic_params() {
check_assist(
introduce_named_generic,
r#"fn foo(bar: $0impl Bar) {}"#,
r#"fn foo<B: Bar>(bar: B) {}"#,
);
}
#[test]
fn replace_two_impl_trait_with_generic_params() {
check_assist(
introduce_named_generic,
r#"fn foo<G>(foo: impl Foo, bar: $0impl Bar) {}"#,
r#"fn foo<G, B: Bar>(foo: impl Foo, bar: B) {}"#,
);
}
#[test]
fn replace_impl_trait_with_empty_generic_params() {
check_assist(
introduce_named_generic,
r#"fn foo<>(bar: $0impl Bar) {}"#,
r#"fn foo<B: Bar>(bar: B) {}"#,
);
}
#[test]
fn replace_impl_trait_with_empty_multiline_generic_params() {
check_assist(
introduce_named_generic,
r#"
fn foo<
>(bar: $0impl Bar) {}
"#,
r#"
fn foo<B: Bar
>(bar: B) {}
"#,
);
}
#[test]
fn replace_impl_trait_with_exist_generic_letter() {
// FIXME: This is wrong, we should pick a different name if the one we
// want is already bound.
check_assist(
introduce_named_generic,
r#"fn foo<B>(bar: $0impl Bar) {}"#,
r#"fn foo<B, B: Bar>(bar: B) {}"#,
);
}
#[test]
fn replace_impl_trait_with_multiline_generic_params() {
check_assist(
introduce_named_generic,
r#"
fn foo<
G: Foo,
F,
H,
>(bar: $0impl Bar) {}
"#,
r#"
fn foo<
G: Foo,
F,
H, B: Bar,
>(bar: B) {}
"#,
);
}
#[test]
fn replace_impl_trait_multiple() {
check_assist(
introduce_named_generic,
r#"fn foo(bar: $0impl Foo + Bar) {}"#,
r#"fn foo<F: Foo + Bar>(bar: F) {}"#,
);
}
}