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|
use crate::{AssistContext, AssistId, Assists};
use ra_syntax::{ast, ast::TypeParamsOwner, AstNode, SyntaxKind};
use std::collections::HashSet;
// Assist: change_lifetime_anon_to_named
//
// Change an anonymous lifetime to a named lifetime.
//
// ```
// impl Cursor<'_<|>> {
// fn node(self) -> &SyntaxNode {
// match self {
// Cursor::Replace(node) | Cursor::Before(node) => node,
// }
// }
// }
// ```
// ->
// ```
// impl<'a> Cursor<'a> {
// fn node(self) -> &SyntaxNode {
// match self {
// Cursor::Replace(node) | Cursor::Before(node) => node,
// }
// }
// }
// ```
// FIXME: How can we handle renaming any one of multiple anonymous lifetimes?
pub(crate) fn change_lifetime_anon_to_named(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let lifetime_token = ctx.find_token_at_offset(SyntaxKind::LIFETIME)?;
let lifetime_arg = ast::LifetimeArg::cast(lifetime_token.parent())?;
if lifetime_arg.syntax().text() != "'_" {
return None;
}
let next_token = lifetime_token.next_token()?;
if next_token.kind() != SyntaxKind::R_ANGLE {
// only allow naming the last anonymous lifetime
return None;
}
match lifetime_arg.syntax().ancestors().find_map(ast::ImplDef::cast) {
Some(impl_def) => {
// get the `impl` keyword so we know where to add the lifetime argument
let impl_kw = impl_def.syntax().first_child_or_token()?.into_token()?;
if impl_kw.kind() != SyntaxKind::IMPL_KW {
return None;
}
let new_lifetime_param = match impl_def.type_param_list() {
Some(type_params) => {
let used_lifetime_params: HashSet<_> = type_params
.lifetime_params()
.map(|p| {
let mut param_name = p.syntax().text().to_string();
param_name.remove(0);
param_name
})
.collect();
"abcdefghijklmnopqrstuvwxyz"
.chars()
.find(|c| !used_lifetime_params.contains(&c.to_string()))?
}
None => 'a',
};
acc.add(
AssistId("change_lifetime_anon_to_named"),
"Give anonymous lifetime a name",
lifetime_arg.syntax().text_range(),
|builder| {
match impl_def.type_param_list() {
Some(type_params) => {
builder.insert(
(u32::from(type_params.syntax().text_range().end()) - 1).into(),
format!(", '{}", new_lifetime_param),
);
}
None => {
builder.insert(
impl_kw.text_range().end(),
format!("<'{}>", new_lifetime_param),
);
}
}
builder.replace(
lifetime_arg.syntax().text_range(),
format!("'{}", new_lifetime_param),
);
},
)
}
_ => None,
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tests::{check_assist, check_assist_not_applicable};
#[test]
fn test_example_case() {
check_assist(
change_lifetime_anon_to_named,
r#"impl Cursor<'_<|>> {
fn node(self) -> &SyntaxNode {
match self {
Cursor::Replace(node) | Cursor::Before(node) => node,
}
}
}"#,
r#"impl<'a> Cursor<'a> {
fn node(self) -> &SyntaxNode {
match self {
Cursor::Replace(node) | Cursor::Before(node) => node,
}
}
}"#,
);
}
#[test]
fn test_example_case_simplified() {
check_assist(
change_lifetime_anon_to_named,
r#"impl Cursor<'_<|>> {"#,
r#"impl<'a> Cursor<'a> {"#,
);
}
#[test]
fn test_not_applicable() {
check_assist_not_applicable(change_lifetime_anon_to_named, r#"impl Cursor<'_><|> {"#);
check_assist_not_applicable(change_lifetime_anon_to_named, r#"impl Cursor<|><'_> {"#);
check_assist_not_applicable(change_lifetime_anon_to_named, r#"impl Cursor<'a<|>> {"#);
}
#[test]
fn test_with_type_parameter() {
check_assist(
change_lifetime_anon_to_named,
r#"impl<T> Cursor<T, '_<|>>"#,
r#"impl<T, 'a> Cursor<T, 'a>"#,
);
}
#[test]
fn test_with_existing_lifetime_name_conflict() {
check_assist(
change_lifetime_anon_to_named,
r#"impl<'a, 'b> Cursor<'a, 'b, '_<|>>"#,
r#"impl<'a, 'b, 'c> Cursor<'a, 'b, 'c>"#,
);
}
}
|
