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|
use ast::LoopBodyOwner;
use ide_db::helpers::FamousDefs;
use stdx::format_to;
use syntax::{ast, AstNode};
use crate::{AssistContext, AssistId, AssistKind, Assists};
// Assist: convert_for_to_iter_for_each
//
// Converts a for loop into a for_each loop on the Iterator.
//
// ```
// fn main() {
// let x = vec![1, 2, 3];
// for $0v in x {
// let y = v * 2;
// }
// }
// ```
// ->
// ```
// fn main() {
// let x = vec![1, 2, 3];
// x.into_iter().for_each(|v| {
// let y = v * 2;
// });
// }
// ```
pub(crate) fn convert_for_to_iter_for_each(acc: &mut Assists, ctx: &AssistContext) -> Option<()> {
let for_loop = ctx.find_node_at_offset::<ast::ForExpr>()?;
let iterable = for_loop.iterable()?;
let pat = for_loop.pat()?;
let body = for_loop.loop_body()?;
let mut buf = String::new();
if impls_core_iter(&ctx.sema, &iterable) {
buf += &iterable.to_string();
} else {
match iterable {
ast::Expr::RefExpr(r) => {
if r.mut_token().is_some() {
format_to!(buf, "{}.iter_mut()", r.expr()?);
} else {
format_to!(buf, "{}.iter()", r.expr()?);
}
}
_ => format_to!(buf, "{}.into_iter()", iterable),
}
}
format_to!(buf, ".for_each(|{}| {});", pat, body);
acc.add(
AssistId("convert_for_to_iter_for_each", AssistKind::RefactorRewrite),
"Convert a for loop into an Iterator::for_each",
for_loop.syntax().text_range(),
|builder| builder.replace(for_loop.syntax().text_range(), buf),
)
}
fn impls_core_iter(sema: &hir::Semantics<ide_db::RootDatabase>, iterable: &ast::Expr) -> bool {
let it_typ = if let Some(i) = sema.type_of_expr(iterable) {
i
} else {
return false;
};
let module = if let Some(m) = sema.scope(iterable.syntax()).module() {
m
} else {
return false;
};
let krate = module.krate();
if let Some(iter_trait) = FamousDefs(sema, Some(krate)).core_iter_Iterator() {
return it_typ.impls_trait(sema.db, iter_trait, &[]);
}
false
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
const EMPTY_ITER_FIXTURE: &'static str = r"
//- /lib.rs deps:core crate:empty_iter
pub struct EmptyIter;
impl Iterator for EmptyIter {
type Item = usize;
fn next(&mut self) -> Option<Self::Item> { None }
}
pub struct Empty;
impl Empty {
pub fn iter(&self) -> EmptyIter { EmptyIter }
}
";
#[test]
fn test_not_for() {
check_assist_not_applicable(
convert_for_to_iter_for_each,
r"
let mut x = vec![1, 2, 3];
x.iter_mut().$0for_each(|v| *v *= 2);
",
)
}
#[test]
fn test_simple_for() {
check_assist(
convert_for_to_iter_for_each,
r"
fn main() {
let x = vec![1, 2, 3];
for $0v in x {
v *= 2;
}
}",
r"
fn main() {
let x = vec![1, 2, 3];
x.into_iter().for_each(|v| {
v *= 2;
});
}",
)
}
#[test]
fn test_for_borrowed() {
check_assist(
convert_for_to_iter_for_each,
r"
fn main() {
let x = vec![1, 2, 3];
for $0v in &x {
let a = v * 2;
}
}",
r"
fn main() {
let x = vec![1, 2, 3];
x.iter().for_each(|v| {
let a = v * 2;
});
}",
)
}
#[test]
fn test_for_borrowed_mut() {
check_assist(
convert_for_to_iter_for_each,
r"
fn main() {
let x = vec![1, 2, 3];
for $0v in &mut x {
*v *= 2;
}
}",
r"
fn main() {
let x = vec![1, 2, 3];
x.iter_mut().for_each(|v| {
*v *= 2;
});
}",
)
}
#[test]
fn test_for_borrowed_mut_behind_var() {
check_assist(
convert_for_to_iter_for_each,
r"
fn main() {
let x = vec![1, 2, 3];
let y = &mut x;
for $0v in y {
*v *= 2;
}
}",
r"
fn main() {
let x = vec![1, 2, 3];
let y = &mut x;
y.into_iter().for_each(|v| {
*v *= 2;
});
}",
)
}
#[test]
fn test_take() {
let before = r#"
use empty_iter::*;
fn main() {
let x = Empty;
for$0 a in x.iter().take(1) {
println!("{}", a);
}
}
"#;
let after = r#"
use empty_iter::*;
fn main() {
let x = Empty;
x.iter().take(1).for_each(|a| {
println!("{}", a);
});
}
"#;
let before = &format!(
"//- /main.rs crate:main deps:core,empty_iter{}{}{}",
before,
FamousDefs::FIXTURE,
EMPTY_ITER_FIXTURE
);
check_assist(convert_for_to_iter_for_each, before, after);
}
}
|
