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Rollup merge of #123344 - pietroalbini:pa-unused-imports, r=Nilstrieb
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Remove braces when fixing a nested use tree into a single item

[Back in 2019](rust-lang/rust#56645) I added rustfix support for the `unused_imports` lint, to automatically remove them when running `cargo fix`. For the most part this worked great, but when removing all but one childs of a nested use tree it turned `use foo::{Unused, Used}` into `use foo::{Used}`. This is slightly annoying, because it then requires you to run `rustfmt` to get `use foo::Used`.

This PR automatically removes braces and the surrouding whitespace when all but one child of a nested use tree are unused. To get it done I had to add the span of the nested use tree to the AST, and refactor a bit the code I wrote back then.

A thing I noticed is, there doesn't seem to be any `//@ run-rustfix` test for fixing the `unused_imports` lint. I created a test in `tests/suggestions` (is that the right directory?) that for now tests just what I added in the PR. I can followup in a separate PR to add more tests for fixing `unused_lints`.

This PR is best reviewed commit-by-commit.
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matthiaskrgr authored May 8, 2024
2 parents 10913d2 + f0f3927 commit eef0828
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Showing 4 changed files with 9 additions and 9 deletions.
8 changes: 4 additions & 4 deletions clippy_lints/src/single_component_path_imports.rs
Original file line number Diff line number Diff line change
Expand Up @@ -201,8 +201,8 @@ impl SingleComponentPathImports {

if segments.is_empty() {
// keep track of `use {some_module, some_other_module};` usages
if let UseTreeKind::Nested(trees) = &use_tree.kind {
for tree in trees {
if let UseTreeKind::Nested { items, .. } = &use_tree.kind {
for tree in items {
let segments = &tree.0.prefix.segments;
if segments.len() == 1 {
if let UseTreeKind::Simple(None) = tree.0.kind {
Expand All @@ -229,8 +229,8 @@ impl SingleComponentPathImports {
}

// nested case such as `use self::{module1::Struct1, module2::Struct2}`
if let UseTreeKind::Nested(trees) = &use_tree.kind {
for tree in trees {
if let UseTreeKind::Nested { items, .. } = &use_tree.kind {
for tree in items {
let segments = &tree.0.prefix.segments;
if !segments.is_empty() {
imports_reused_with_self.push(segments[0].ident.name);
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4 changes: 2 additions & 2 deletions clippy_lints/src/unnecessary_self_imports.rs
Original file line number Diff line number Diff line change
Expand Up @@ -36,8 +36,8 @@ declare_lint_pass!(UnnecessarySelfImports => [UNNECESSARY_SELF_IMPORTS]);
impl EarlyLintPass for UnnecessarySelfImports {
fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
if let ItemKind::Use(use_tree) = &item.kind
&& let UseTreeKind::Nested(nodes) = &use_tree.kind
&& let [(self_tree, _)] = &**nodes
&& let UseTreeKind::Nested { items, .. } = &use_tree.kind
&& let [(self_tree, _)] = &**items
&& let [self_seg] = &*self_tree.prefix.segments
&& self_seg.ident.name == kw::SelfLower
&& let Some(last_segment) = use_tree.prefix.segments.last()
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4 changes: 2 additions & 2 deletions clippy_lints/src/unsafe_removed_from_name.rs
Original file line number Diff line number Diff line change
Expand Up @@ -49,8 +49,8 @@ fn check_use_tree(use_tree: &UseTree, cx: &EarlyContext<'_>, span: Span) {
unsafe_to_safe_check(old_name, new_name, cx, span);
},
UseTreeKind::Simple(None) | UseTreeKind::Glob => {},
UseTreeKind::Nested(ref nested_use_tree) => {
for (use_tree, _) in nested_use_tree {
UseTreeKind::Nested { ref items, .. } => {
for (use_tree, _) in items {
check_use_tree(use_tree, cx, span);
}
},
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2 changes: 1 addition & 1 deletion clippy_utils/src/ast_utils.rs
Original file line number Diff line number Diff line change
Expand Up @@ -648,7 +648,7 @@ pub fn eq_use_tree_kind(l: &UseTreeKind, r: &UseTreeKind) -> bool {
match (l, r) {
(Glob, Glob) => true,
(Simple(l), Simple(r)) => both(l, r, |l, r| eq_id(*l, *r)),
(Nested(l), Nested(r)) => over(l, r, |(l, _), (r, _)| eq_use_tree(l, r)),
(Nested { items: l, .. }, Nested { items: r, .. }) => over(l, r, |(l, _), (r, _)| eq_use_tree(l, r)),
_ => false,
}
}
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