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convert_iter_for_each_to_for.rs
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convert_iter_for_each_to_for.rs
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use hir::known;
use ide_db::famous_defs::FamousDefs;
use stdx::format_to;
use syntax::{
ast::{self, edit_in_place::Indent, make, HasArgList, HasLoopBody},
AstNode,
};
use crate::{AssistContext, AssistId, AssistKind, Assists};
// Assist: convert_iter_for_each_to_for
//
// Converts an Iterator::for_each function into a for loop.
//
// ```
// # //- minicore: iterators
// # use core::iter;
// fn main() {
// let iter = iter::repeat((9, 2));
// iter.for_each$0(|(x, y)| {
// println!("x: {}, y: {}", x, y);
// });
// }
// ```
// ->
// ```
// # use core::iter;
// fn main() {
// let iter = iter::repeat((9, 2));
// for (x, y) in iter {
// println!("x: {}, y: {}", x, y);
// }
// }
// ```
pub(crate) fn convert_iter_for_each_to_for(
acc: &mut Assists,
ctx: &AssistContext<'_>,
) -> Option<()> {
let method = ctx.find_node_at_offset::<ast::MethodCallExpr>()?;
let closure = match method.arg_list()?.args().next()? {
ast::Expr::ClosureExpr(expr) => expr,
_ => return None,
};
let (method, receiver) = validate_method_call_expr(ctx, method)?;
let param_list = closure.param_list()?;
let param = param_list.params().next()?.pat()?;
let body = closure.body()?;
let stmt = method.syntax().parent().and_then(ast::ExprStmt::cast);
let range = stmt.as_ref().map_or(method.syntax(), AstNode::syntax).text_range();
acc.add(
AssistId("convert_iter_for_each_to_for", AssistKind::RefactorRewrite),
"Replace this `Iterator::for_each` with a for loop",
range,
|builder| {
let indent =
stmt.as_ref().map_or_else(|| method.indent_level(), ast::ExprStmt::indent_level);
let block = match body {
ast::Expr::BlockExpr(block) => block,
_ => make::block_expr(Vec::new(), Some(body)),
}
.clone_for_update();
block.reindent_to(indent);
let expr_for_loop = make::expr_for_loop(param, receiver, block);
builder.replace(range, expr_for_loop.to_string())
},
)
}
// Assist: convert_for_loop_with_for_each
//
// Converts a for loop into a for_each loop on the Iterator.
//
// ```
// fn main() {
// let x = vec![1, 2, 3];
// for$0 v 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_loop_with_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()?;
if body.syntax().text_range().start() < ctx.offset() {
cov_mark::hit!(not_available_in_body);
return None;
}
acc.add(
AssistId("convert_for_loop_with_for_each", AssistKind::RefactorRewrite),
"Replace this for loop with `Iterator::for_each`",
for_loop.syntax().text_range(),
|builder| {
let mut buf = String::new();
if let Some((expr_behind_ref, method)) =
is_ref_and_impls_iter_method(&ctx.sema, &iterable)
{
// We have either "for x in &col" and col implements a method called iter
// or "for x in &mut col" and col implements a method called iter_mut
format_to!(buf, "{expr_behind_ref}.{}()", method.display(ctx.db()));
} else if let ast::Expr::RangeExpr(..) = iterable {
// range expressions need to be parenthesized for the syntax to be correct
format_to!(buf, "({iterable})");
} else if impls_core_iter(&ctx.sema, &iterable) {
format_to!(buf, "{iterable}");
} else if let ast::Expr::RefExpr(_) = iterable {
format_to!(buf, "({iterable}).into_iter()");
} else {
format_to!(buf, "{iterable}.into_iter()");
}
format_to!(buf, ".for_each(|{pat}| {body});");
builder.replace(for_loop.syntax().text_range(), buf)
},
)
}
/// If iterable is a reference where the expression behind the reference implements a method
/// returning an Iterator called iter or iter_mut (depending on the type of reference) then return
/// the expression behind the reference and the method name
fn is_ref_and_impls_iter_method(
sema: &hir::Semantics<'_, ide_db::RootDatabase>,
iterable: &ast::Expr,
) -> Option<(ast::Expr, hir::Name)> {
let ref_expr = match iterable {
ast::Expr::RefExpr(r) => r,
_ => return None,
};
let wanted_method = if ref_expr.mut_token().is_some() { known::iter_mut } else { known::iter };
let expr_behind_ref = ref_expr.expr()?;
let ty = sema.type_of_expr(&expr_behind_ref)?.adjusted();
let scope = sema.scope(iterable.syntax())?;
let krate = scope.krate();
let iter_trait = FamousDefs(sema, krate).core_iter_Iterator()?;
let has_wanted_method = ty
.iterate_method_candidates(sema.db, &scope, None, Some(&wanted_method), |func| {
if func.ret_type(sema.db).impls_trait(sema.db, iter_trait, &[]) {
return Some(());
}
None
})
.is_some();
if !has_wanted_method {
return None;
}
Some((expr_behind_ref, wanted_method))
}
/// Whether iterable implements core::Iterator
fn impls_core_iter(sema: &hir::Semantics<'_, ide_db::RootDatabase>, iterable: &ast::Expr) -> bool {
(|| {
let it_typ = sema.type_of_expr(iterable)?.adjusted();
let module = sema.scope(iterable.syntax())?.module();
let krate = module.krate();
let iter_trait = FamousDefs(sema, krate).core_iter_Iterator()?;
cov_mark::hit!(test_already_impls_iterator);
Some(it_typ.impls_trait(sema.db, iter_trait, &[]))
})()
.unwrap_or(false)
}
fn validate_method_call_expr(
ctx: &AssistContext<'_>,
expr: ast::MethodCallExpr,
) -> Option<(ast::Expr, ast::Expr)> {
let name_ref = expr.name_ref()?;
if !name_ref.syntax().text_range().contains_range(ctx.selection_trimmed()) {
cov_mark::hit!(test_for_each_not_applicable_invalid_cursor_pos);
return None;
}
if name_ref.text() != "for_each" {
return None;
}
let sema = &ctx.sema;
let receiver = expr.receiver()?;
let expr = ast::Expr::MethodCallExpr(expr);
let it_type = sema.type_of_expr(&receiver)?.adjusted();
let module = sema.scope(receiver.syntax())?.module();
let krate = module.krate();
let iter_trait = FamousDefs(sema, krate).core_iter_Iterator()?;
it_type.impls_trait(sema.db, iter_trait, &[]).then_some((expr, receiver))
}
#[cfg(test)]
mod tests {
use crate::tests::{check_assist, check_assist_not_applicable};
use super::*;
#[test]
fn test_for_each_in_method_stmt() {
check_assist(
convert_iter_for_each_to_for,
r#"
//- minicore: iterators
fn main() {
let it = core::iter::repeat(92);
it.$0for_each(|(x, y)| {
println!("x: {}, y: {}", x, y);
});
}
"#,
r#"
fn main() {
let it = core::iter::repeat(92);
for (x, y) in it {
println!("x: {}, y: {}", x, y);
}
}
"#,
)
}
#[test]
fn test_for_each_in_method() {
check_assist(
convert_iter_for_each_to_for,
r#"
//- minicore: iterators
fn main() {
let it = core::iter::repeat(92);
it.$0for_each(|(x, y)| {
println!("x: {}, y: {}", x, y);
})
}
"#,
r#"
fn main() {
let it = core::iter::repeat(92);
for (x, y) in it {
println!("x: {}, y: {}", x, y);
}
}
"#,
)
}
#[test]
fn test_for_each_without_braces_stmt() {
check_assist(
convert_iter_for_each_to_for,
r#"
//- minicore: iterators
fn main() {
let it = core::iter::repeat(92);
it.$0for_each(|(x, y)| println!("x: {}, y: {}", x, y));
}
"#,
r#"
fn main() {
let it = core::iter::repeat(92);
for (x, y) in it {
println!("x: {}, y: {}", x, y)
}
}
"#,
)
}
#[test]
fn test_for_each_not_applicable() {
check_assist_not_applicable(
convert_iter_for_each_to_for,
r#"
//- minicore: iterators
fn main() {
().$0for_each(|x| println!("{}", x));
}"#,
)
}
#[test]
fn test_for_each_not_applicable_invalid_cursor_pos() {
cov_mark::check!(test_for_each_not_applicable_invalid_cursor_pos);
check_assist_not_applicable(
convert_iter_for_each_to_for,
r#"
//- minicore: iterators
fn main() {
core::iter::repeat(92).for_each(|(x, y)| $0println!("x: {}, y: {}", x, y));
}"#,
)
}
#[test]
fn each_to_for_not_for() {
check_assist_not_applicable(
convert_for_loop_with_for_each,
r"
let mut x = vec![1, 2, 3];
x.iter_mut().$0for_each(|v| *v *= 2);
",
)
}
#[test]
fn each_to_for_simple_for() {
check_assist(
convert_for_loop_with_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 each_to_for_for_in_range() {
check_assist(
convert_for_loop_with_for_each,
r#"
//- minicore: range, iterators
impl<T> core::iter::Iterator for core::ops::Range<T> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
None
}
}
fn main() {
for $0x in 0..92 {
print!("{}", x);
}
}"#,
r#"
impl<T> core::iter::Iterator for core::ops::Range<T> {
type Item = T;
fn next(&mut self) -> Option<Self::Item> {
None
}
}
fn main() {
(0..92).for_each(|x| {
print!("{}", x);
});
}"#,
)
}
#[test]
fn each_to_for_not_available_in_body() {
cov_mark::check!(not_available_in_body);
check_assist_not_applicable(
convert_for_loop_with_for_each,
r"
fn main() {
let x = vec![1, 2, 3];
for v in x {
$0v *= 2;
}
}",
)
}
#[test]
fn each_to_for_for_borrowed() {
check_assist(
convert_for_loop_with_for_each,
r#"
//- minicore: iterators
use core::iter::{Repeat, repeat};
struct S;
impl S {
fn iter(&self) -> Repeat<i32> { repeat(92) }
fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
}
fn main() {
let x = S;
for $0v in &x {
let a = v * 2;
}
}
"#,
r#"
use core::iter::{Repeat, repeat};
struct S;
impl S {
fn iter(&self) -> Repeat<i32> { repeat(92) }
fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
}
fn main() {
let x = S;
x.iter().for_each(|v| {
let a = v * 2;
});
}
"#,
)
}
#[test]
fn each_to_for_for_borrowed_no_iter_method() {
check_assist(
convert_for_loop_with_for_each,
r"
struct NoIterMethod;
fn main() {
let x = NoIterMethod;
for $0v in &x {
let a = v * 2;
}
}
",
r"
struct NoIterMethod;
fn main() {
let x = NoIterMethod;
(&x).into_iter().for_each(|v| {
let a = v * 2;
});
}
",
)
}
#[test]
fn each_to_for_for_borrowed_mut() {
check_assist(
convert_for_loop_with_for_each,
r#"
//- minicore: iterators
use core::iter::{Repeat, repeat};
struct S;
impl S {
fn iter(&self) -> Repeat<i32> { repeat(92) }
fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
}
fn main() {
let x = S;
for $0v in &mut x {
let a = v * 2;
}
}
"#,
r#"
use core::iter::{Repeat, repeat};
struct S;
impl S {
fn iter(&self) -> Repeat<i32> { repeat(92) }
fn iter_mut(&mut self) -> Repeat<i32> { repeat(92) }
}
fn main() {
let x = S;
x.iter_mut().for_each(|v| {
let a = v * 2;
});
}
"#,
)
}
#[test]
fn each_to_for_for_borrowed_mut_behind_var() {
check_assist(
convert_for_loop_with_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 each_to_for_already_impls_iterator() {
cov_mark::check!(test_already_impls_iterator);
check_assist(
convert_for_loop_with_for_each,
r#"
//- minicore: iterators
fn main() {
for$0 a in core::iter::repeat(92).take(1) {
println!("{}", a);
}
}
"#,
r#"
fn main() {
core::iter::repeat(92).take(1).for_each(|a| {
println!("{}", a);
});
}
"#,
);
}
}