rust/crates/ra_assists/src/handlers/add_turbo_fish.rs
2020-05-20 13:00:50 +02:00

135 lines
2.8 KiB
Rust

use ra_ide_db::defs::{classify_name_ref, Definition, NameRefClass};
use ra_syntax::{ast, AstNode, SyntaxKind, T};
use test_utils::mark;
use crate::{
assist_context::{AssistContext, Assists},
AssistId,
};
// Assist: add_turbo_fish
//
// Adds `::<_>` to a call of a generic method or function.
//
// ```
// fn make<T>() -> T { todo!() }
// fn main() {
// let x = make<|>();
// }
// ```
// ->
// ```
// fn make<T>() -> T { todo!() }
// fn main() {
// let x = make::<${0:_}>();
// }
// ```
pub(crate) fn add_turbo_fish(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let ident = ctx.find_token_at_offset(SyntaxKind::IDENT)?;
let next_token = ident.next_token()?;
if next_token.kind() == T![::] {
mark::hit!(add_turbo_fish_one_fish_is_enough);
return None;
}
let name_ref = ast::NameRef::cast(ident.parent())?;
let def = match classify_name_ref(&ctx.sema, &name_ref)? {
NameRefClass::Definition(def) => def,
NameRefClass::FieldShorthand { .. } => return None,
};
let fun = match def {
Definition::ModuleDef(hir::ModuleDef::Function(it)) => it,
_ => return None,
};
let generics = hir::GenericDef::Function(fun).params(ctx.sema.db);
if generics.is_empty() {
mark::hit!(add_turbo_fish_non_generic);
return None;
}
acc.add(AssistId("add_turbo_fish"), "Add `::<>`", ident.text_range(), |builder| {
match ctx.config.snippet_cap {
Some(cap) => builder.insert_snippet(cap, ident.text_range().end(), "::<${0:_}>"),
None => builder.insert(ident.text_range().end(), "::<_>"),
}
})
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
use test_utils::mark;
#[test]
fn add_turbo_fish_function() {
check_assist(
add_turbo_fish,
r#"
fn make<T>() -> T {}
fn main() {
make<|>();
}
"#,
r#"
fn make<T>() -> T {}
fn main() {
make::<${0:_}>();
}
"#,
);
}
#[test]
fn add_turbo_fish_method() {
check_assist(
add_turbo_fish,
r#"
struct S;
impl S {
fn make<T>(&self) -> T {}
}
fn main() {
S.make<|>();
}
"#,
r#"
struct S;
impl S {
fn make<T>(&self) -> T {}
}
fn main() {
S.make::<${0:_}>();
}
"#,
);
}
#[test]
fn add_turbo_fish_one_fish_is_enough() {
mark::check!(add_turbo_fish_one_fish_is_enough);
check_assist_not_applicable(
add_turbo_fish,
r#"
fn make<T>() -> T {}
fn main() {
make<|>::<()>();
}
"#,
);
}
#[test]
fn add_turbo_fish_non_generic() {
mark::check!(add_turbo_fish_non_generic);
check_assist_not_applicable(
add_turbo_fish,
r#"
fn make() -> () {}
fn main() {
make<|>();
}
"#,
);
}
}