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|
use ide_db::defs::{Definition, NameRefClass};
use syntax::{ast, AstNode, SyntaxKind, T};
use test_utils::mark;
use crate::{
assist_context::{AssistContext, Assists},
AssistId, AssistKind,
};
// Assist: add_type_ascription
//
// Adds `: _` before the assignment operator to prompt the user for a type
//
// ```
// fn make<T>() -> T { todo!() }
// fn main() {
// let x = make$0();
// }
// ```
// ->
// ```
// fn make<T>() -> T { todo!() }
// fn main() {
// let x: ${0:_} = make();
// }
// ```
pub(crate) fn add_type_ascription(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let let_stmt = ctx.find_node_at_offset::<ast::LetStmt>()?;
if let_stmt.colon_token().is_some() {
mark::hit!(add_type_ascription_already_typed);
return None
}
let ident = ctx.find_token_syntax_at_offset(SyntaxKind::IDENT).or_else(|| {
let arg_list = ctx.find_node_at_offset::<ast::ArgList>()?;
if arg_list.args().count() > 0 {
return None;
}
mark::hit!(add_type_ascription_after_call);
arg_list.l_paren_token()?.prev_token().filter(|it| it.kind() == SyntaxKind::IDENT)
})?;
let next_token = ident.next_token()?;
if next_token.kind() == T![::] {
mark::hit!(add_type_ascription_turbofished);
return None;
}
let name_ref = ast::NameRef::cast(ident.parent())?;
let def = match NameRefClass::classify(&ctx.sema, &name_ref)? {
NameRefClass::Definition(def) => def,
NameRefClass::ExternCrate(_) | 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_type_ascription_non_generic);
return None;
}
let pat = let_stmt.pat()?.syntax().last_token()?.text_range().end();
acc.add(
AssistId("add_type_ascription", AssistKind::RefactorRewrite),
"Add `: _` before assignment operator",
ident.text_range(),
|builder| match ctx.config.snippet_cap {
Some(cap) => builder.insert_snippet(cap, pat, ": ${0:_}"),
None => builder.insert(pat, ": _"),
},
)
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
use test_utils::mark;
#[test]
fn add_type_ascription_function() {
check_assist(
add_type_ascription,
r#"
fn make<T>() -> T {}
fn main() {
let x = make$0();
}
"#,
r#"
fn make<T>() -> T {}
fn main() {
let x: ${0:_} = make();
}
"#,
);
}
#[test]
fn add_type_ascription_after_call() {
mark::check!(add_type_ascription_after_call);
check_assist(
add_type_ascription,
r#"
fn make<T>() -> T {}
fn main() {
let x = make()$0;
}
"#,
r#"
fn make<T>() -> T {}
fn main() {
let x: ${0:_} = make();
}
"#,
);
}
#[test]
fn add_type_ascription_method() {
check_assist(
add_type_ascription,
r#"
struct S;
impl S {
fn make<T>(&self) -> T {}
}
fn main() {
let x = S.make$0();
}
"#,
r#"
struct S;
impl S {
fn make<T>(&self) -> T {}
}
fn main() {
let x: ${0:_} = S.make();
}
"#,
);
}
#[test]
fn add_type_ascription_turbofished() {
mark::check!(add_type_ascription_turbofished);
check_assist_not_applicable(
add_type_ascription,
r#"
fn make<T>() -> T {}
fn main() {
let x = make$0::<()>();
}
"#,
);
}
#[test]
fn add_type_ascription_already_typed() {
mark::check!(add_type_ascription_already_typed);
check_assist_not_applicable(
add_type_ascription,
r#"
fn make<T>() -> T {}
fn main() {
let x: () = make$0();
}
"#,
);
}
#[test]
fn add_type_ascription_non_generic() {
mark::check!(add_type_ascription_non_generic);
check_assist_not_applicable(
add_type_ascription,
r#"
fn make() -> () {}
fn main() {
let x = make$0();
}
"#,
);
}
#[test]
fn add_type_ascription_no_let() {
check_assist_not_applicable(
add_type_ascription,
r#"
fn make<T>() -> T {}
fn main() {
make$0();
}
"#,
);
}
}
|
