From 506293ca43f4cae7520c9e14b6b36b42b1af4ce1 Mon Sep 17 00:00:00 2001
From: Matt Hall <matthew@quickbeam.me.uk>
Date: Sun, 21 Feb 2021 17:36:37 +0000
Subject: Add convert_for_to_iter_for_each assist
---
.../src/handlers/convert_for_to_iter_for_each.rs | 225 +++++++++++++++++++++
crates/ide_assists/src/lib.rs | 2 +
crates/ide_assists/src/tests/generated.rs | 23 +++
3 files changed, 250 insertions(+)
create mode 100644 crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs
diff --git a/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs b/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs
new file mode 100644
index 000000000..d858474c6
--- /dev/null
+++ b/crates/ide_assists/src/handlers/convert_for_to_iter_for_each.rs
@@ -0,0 +1,225 @@
+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);
+ }
+}
diff --git a/crates/ide_assists/src/lib.rs b/crates/ide_assists/src/lib.rs
index 7067cf8b6..f4c7e6fbf 100644
--- a/crates/ide_assists/src/lib.rs
+++ b/crates/ide_assists/src/lib.rs
@@ -114,6 +114,7 @@ mod handlers {
mod apply_demorgan;
mod auto_import;
mod change_visibility;
+ mod convert_for_to_iter_for_each;
mod convert_integer_literal;
mod early_return;
mod expand_glob_import;
@@ -175,6 +176,7 @@ mod handlers {
apply_demorgan::apply_demorgan,
auto_import::auto_import,
change_visibility::change_visibility,
+ convert_for_to_iter_for_each::convert_for_to_iter_for_each,
convert_integer_literal::convert_integer_literal,
early_return::convert_to_guarded_return,
expand_glob_import::expand_glob_import,
diff --git a/crates/ide_assists/src/tests/generated.rs b/crates/ide_assists/src/tests/generated.rs
index 0516deaff..100c3b7fe 100644
--- a/crates/ide_assists/src/tests/generated.rs
+++ b/crates/ide_assists/src/tests/generated.rs
@@ -192,6 +192,29 @@ pub(crate) fn frobnicate() {}
)
}
+#[test]
+fn doctest_convert_for_to_iter_for_each() {
+ check_doc_test(
+ "convert_for_to_iter_for_each",
+ r#####"
+fn main() {
+ let x = vec![1, 2, 3];
+ for $0v in x {
+ let y = v * 2;
+ }
+}
+"#####,
+ r#####"
+fn main() {
+ let x = vec![1, 2, 3];
+ x.into_iter().for_each(|v| {
+ let y = v * 2;
+ });
+}
+"#####,
+ )
+}
+
#[test]
fn doctest_convert_integer_literal() {
check_doc_test(
--
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