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|
use syntax::ast::{self, edit::AstNodeEdit, make, AstNode, GenericParamsOwner};
use crate::{AssistContext, AssistId, AssistKind, Assists};
// Assist: replace_impl_trait_with_generic
//
// Replaces `impl Trait` function argument with the named generic.
//
// ```
// fn foo<G>(bar: <|>impl Bar) {}
// ```
// ->
// ```
// fn foo<B: Bar>(bar: B) {}
// ```
pub(crate) fn replace_impl_trait_with_generic(
acc: &mut Assists,
ctx: &AssistContext,
) -> Option<()> {
let type_impl_trait = ctx.find_node_at_offset::<ast::ImplTraitType>()?;
let type_param = type_impl_trait.syntax().parent().and_then(ast::Param::cast)?;
let type_fn = type_param.syntax().ancestors().find_map(ast::Fn::cast)?;
let impl_trait_ty = type_impl_trait
.syntax()
.descendants()
.last()
.and_then(ast::NameRef::cast)?
.text()
.to_string();
let target = type_fn.syntax().text_range();
acc.add(
AssistId("replace_impl_trait_with_generic", AssistKind::RefactorRewrite),
"Replace impl trait with generic",
target,
|edit| {
let generic_letter = impl_trait_ty.chars().next().unwrap().to_string();
let generic_param_list = type_fn
.generic_param_list()
.unwrap_or_else(|| make::generic_param_list(None))
.append_param(make::generic_param(generic_letter.clone(), Some(impl_trait_ty)));
let new_type_fn = type_fn
.replace_descendant::<ast::Type>(type_impl_trait.into(), make::ty(&generic_letter))
.with_generic_param_list(generic_param_list);
edit.replace_ast(type_fn.clone(), new_type_fn);
},
)
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tests::check_assist;
#[test]
fn replace_impl_trait_with_generic_params() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo<G>(bar: <|>impl Bar) {}
"#,
r#"
fn foo<G, B: Bar>(bar: B) {}
"#,
);
}
#[test]
fn replace_impl_trait_without_generic_params() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo(bar: <|>impl Bar) {}
"#,
r#"
fn foo<B: Bar>(bar: B) {}
"#,
);
}
#[test]
fn replace_two_impl_trait_with_generic_params() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo<G>(foo: impl Foo, bar: <|>impl Bar) {}
"#,
r#"
fn foo<G, B: Bar>(foo: impl Foo, bar: B) {}
"#,
);
}
#[test]
fn replace_impl_trait_with_empty_generic_params() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo<>(bar: <|>impl Bar) {}
"#,
r#"
fn foo<B: Bar>(bar: B) {}
"#,
);
}
#[test]
fn replace_impl_trait_with_empty_multiline_generic_params() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo<
>(bar: <|>impl Bar) {}
"#,
r#"
fn foo<B: Bar,
>(bar: B) {}
"#,
);
}
#[test]
#[ignore = "This case is very rare but there is no simple solutions to fix it."]
fn replace_impl_trait_with_exist_generic_letter() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo<B>(bar: <|>impl Bar) {}
"#,
r#"
fn foo<B, C: Bar>(bar: C) {}
"#,
);
}
#[test]
fn replace_impl_trait_with_multiline_generic_params() {
check_assist(
replace_impl_trait_with_generic,
r#"
fn foo<
G: Foo,
F,
H,
>(bar: <|>impl Bar) {}
"#,
r#"
fn foo<
G: Foo,
F,
H, B: Bar,
>(bar: B) {}
"#,
);
}
}
|