From fc34403018079ea053f26d0a31b7517053c7dd8c Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Thu, 13 Aug 2020 17:33:38 +0200 Subject: Rename ra_assists -> assists --- .../src/handlers/introduce_named_lifetime.rs | 318 +++++++++++++++++++++ 1 file changed, 318 insertions(+) create mode 100644 crates/assists/src/handlers/introduce_named_lifetime.rs (limited to 'crates/assists/src/handlers/introduce_named_lifetime.rs') diff --git a/crates/assists/src/handlers/introduce_named_lifetime.rs b/crates/assists/src/handlers/introduce_named_lifetime.rs new file mode 100644 index 000000000..5f623e5f7 --- /dev/null +++ b/crates/assists/src/handlers/introduce_named_lifetime.rs @@ -0,0 +1,318 @@ +use rustc_hash::FxHashSet; +use syntax::{ + ast::{self, GenericParamsOwner, NameOwner}, + AstNode, SyntaxKind, TextRange, TextSize, +}; + +use crate::{assist_context::AssistBuilder, AssistContext, AssistId, AssistKind, Assists}; + +static ASSIST_NAME: &str = "introduce_named_lifetime"; +static ASSIST_LABEL: &str = "Introduce named lifetime"; + +// Assist: introduce_named_lifetime +// +// 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? +// FIXME: should also add support for the case fun(f: &Foo) -> &<|>Foo +pub(crate) fn introduce_named_lifetime(acc: &mut Assists, ctx: &AssistContext) -> Option<()> { + let lifetime_token = ctx + .find_token_at_offset(SyntaxKind::LIFETIME) + .filter(|lifetime| lifetime.text() == "'_")?; + if let Some(fn_def) = lifetime_token.ancestors().find_map(ast::Fn::cast) { + generate_fn_def_assist(acc, &fn_def, lifetime_token.text_range()) + } else if let Some(impl_def) = lifetime_token.ancestors().find_map(ast::Impl::cast) { + generate_impl_def_assist(acc, &impl_def, lifetime_token.text_range()) + } else { + None + } +} + +/// Generate the assist for the fn def case +fn generate_fn_def_assist( + acc: &mut Assists, + fn_def: &ast::Fn, + lifetime_loc: TextRange, +) -> Option<()> { + let param_list: ast::ParamList = fn_def.param_list()?; + let new_lifetime_param = generate_unique_lifetime_param_name(&fn_def.generic_param_list())?; + let end_of_fn_ident = fn_def.name()?.ident_token()?.text_range().end(); + let self_param = + // use the self if it's a reference and has no explicit lifetime + param_list.self_param().filter(|p| p.lifetime_token().is_none() && p.amp_token().is_some()); + // compute the location which implicitly has the same lifetime as the anonymous lifetime + let loc_needing_lifetime = if let Some(self_param) = self_param { + // if we have a self reference, use that + Some(self_param.self_token()?.text_range().start()) + } else { + // otherwise, if there's a single reference parameter without a named liftime, use that + let fn_params_without_lifetime: Vec<_> = param_list + .params() + .filter_map(|param| match param.ty() { + Some(ast::Type::RefType(ascribed_type)) + if ascribed_type.lifetime_token() == None => + { + Some(ascribed_type.amp_token()?.text_range().end()) + } + _ => None, + }) + .collect(); + match fn_params_without_lifetime.len() { + 1 => Some(fn_params_without_lifetime.into_iter().nth(0)?), + 0 => None, + // multiple unnnamed is invalid. assist is not applicable + _ => return None, + } + }; + acc.add(AssistId(ASSIST_NAME, AssistKind::Refactor), ASSIST_LABEL, lifetime_loc, |builder| { + add_lifetime_param(fn_def, builder, end_of_fn_ident, new_lifetime_param); + builder.replace(lifetime_loc, format!("'{}", new_lifetime_param)); + loc_needing_lifetime.map(|loc| builder.insert(loc, format!("'{} ", new_lifetime_param))); + }) +} + +/// Generate the assist for the impl def case +fn generate_impl_def_assist( + acc: &mut Assists, + impl_def: &ast::Impl, + lifetime_loc: TextRange, +) -> Option<()> { + let new_lifetime_param = generate_unique_lifetime_param_name(&impl_def.generic_param_list())?; + let end_of_impl_kw = impl_def.impl_token()?.text_range().end(); + acc.add(AssistId(ASSIST_NAME, AssistKind::Refactor), ASSIST_LABEL, lifetime_loc, |builder| { + add_lifetime_param(impl_def, builder, end_of_impl_kw, new_lifetime_param); + builder.replace(lifetime_loc, format!("'{}", new_lifetime_param)); + }) +} + +/// Given a type parameter list, generate a unique lifetime parameter name +/// which is not in the list +fn generate_unique_lifetime_param_name( + existing_type_param_list: &Option, +) -> Option { + match existing_type_param_list { + Some(type_params) => { + let used_lifetime_params: FxHashSet<_> = type_params + .lifetime_params() + .map(|p| p.syntax().text().to_string()[1..].to_owned()) + .collect(); + (b'a'..=b'z').map(char::from).find(|c| !used_lifetime_params.contains(&c.to_string())) + } + None => Some('a'), + } +} + +/// Add the lifetime param to `builder`. If there are type parameters in `type_params_owner`, add it to the end. Otherwise +/// add new type params brackets with the lifetime parameter at `new_type_params_loc`. +fn add_lifetime_param( + type_params_owner: &TypeParamsOwner, + builder: &mut AssistBuilder, + new_type_params_loc: TextSize, + new_lifetime_param: char, +) { + match type_params_owner.generic_param_list() { + // add the new lifetime parameter to an existing type param list + Some(type_params) => { + builder.insert( + (u32::from(type_params.syntax().text_range().end()) - 1).into(), + format!(", '{}", new_lifetime_param), + ); + } + // create a new type param list containing only the new lifetime parameter + None => { + builder.insert(new_type_params_loc, format!("<'{}>", new_lifetime_param)); + } + } +} + +#[cfg(test)] +mod tests { + use super::*; + use crate::tests::{check_assist, check_assist_not_applicable}; + + #[test] + fn test_example_case() { + check_assist( + introduce_named_lifetime, + 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( + introduce_named_lifetime, + r#"impl Cursor<'_<|>> {"#, + r#"impl<'a> Cursor<'a> {"#, + ); + } + + #[test] + fn test_example_case_cursor_after_tick() { + check_assist( + introduce_named_lifetime, + r#"impl Cursor<'<|>_> {"#, + r#"impl<'a> Cursor<'a> {"#, + ); + } + + #[test] + fn test_impl_with_other_type_param() { + check_assist( + introduce_named_lifetime, + "impl fmt::Display for SepByBuilder<'_<|>, I> + where + I: Iterator, + I::Item: fmt::Display, + {", + "impl fmt::Display for SepByBuilder<'a, I> + where + I: Iterator, + I::Item: fmt::Display, + {", + ) + } + + #[test] + fn test_example_case_cursor_before_tick() { + check_assist( + introduce_named_lifetime, + r#"impl Cursor<<|>'_> {"#, + r#"impl<'a> Cursor<'a> {"#, + ); + } + + #[test] + fn test_not_applicable_cursor_position() { + check_assist_not_applicable(introduce_named_lifetime, r#"impl Cursor<'_><|> {"#); + check_assist_not_applicable(introduce_named_lifetime, r#"impl Cursor<|><'_> {"#); + } + + #[test] + fn test_not_applicable_lifetime_already_name() { + check_assist_not_applicable(introduce_named_lifetime, r#"impl Cursor<'a<|>> {"#); + check_assist_not_applicable(introduce_named_lifetime, r#"fn my_fun<'a>() -> X<'a<|>>"#); + } + + #[test] + fn test_with_type_parameter() { + check_assist( + introduce_named_lifetime, + r#"impl Cursor>"#, + r#"impl Cursor"#, + ); + } + + #[test] + fn test_with_existing_lifetime_name_conflict() { + check_assist( + introduce_named_lifetime, + r#"impl<'a, 'b> Cursor<'a, 'b, '_<|>>"#, + r#"impl<'a, 'b, 'c> Cursor<'a, 'b, 'c>"#, + ); + } + + #[test] + fn test_function_return_value_anon_lifetime_param() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun() -> X<'_<|>>"#, + r#"fn my_fun<'a>() -> X<'a>"#, + ); + } + + #[test] + fn test_function_return_value_anon_reference_lifetime() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun() -> &'_<|> X"#, + r#"fn my_fun<'a>() -> &'a X"#, + ); + } + + #[test] + fn test_function_param_anon_lifetime() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun(x: X<'_<|>>)"#, + r#"fn my_fun<'a>(x: X<'a>)"#, + ); + } + + #[test] + fn test_function_add_lifetime_to_params() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun(f: &Foo) -> X<'_<|>>"#, + r#"fn my_fun<'a>(f: &'a Foo) -> X<'a>"#, + ); + } + + #[test] + fn test_function_add_lifetime_to_params_in_presence_of_other_lifetime() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun<'other>(f: &Foo, b: &'other Bar) -> X<'_<|>>"#, + r#"fn my_fun<'other, 'a>(f: &'a Foo, b: &'other Bar) -> X<'a>"#, + ); + } + + #[test] + fn test_function_not_applicable_without_self_and_multiple_unnamed_param_lifetimes() { + // this is not permitted under lifetime elision rules + check_assist_not_applicable( + introduce_named_lifetime, + r#"fn my_fun(f: &Foo, b: &Bar) -> X<'_<|>>"#, + ); + } + + #[test] + fn test_function_add_lifetime_to_self_ref_param() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun<'other>(&self, f: &Foo, b: &'other Bar) -> X<'_<|>>"#, + r#"fn my_fun<'other, 'a>(&'a self, f: &Foo, b: &'other Bar) -> X<'a>"#, + ); + } + + #[test] + fn test_function_add_lifetime_to_param_with_non_ref_self() { + check_assist( + introduce_named_lifetime, + r#"fn my_fun<'other>(self, f: &Foo, b: &'other Bar) -> X<'_<|>>"#, + r#"fn my_fun<'other, 'a>(self, f: &'a Foo, b: &'other Bar) -> X<'a>"#, + ); + } +} -- cgit v1.2.3