diff --git a/clippy_lints/src/single_component_path_imports.rs b/clippy_lints/src/single_component_path_imports.rs index c9d72aabb6a3c..6104103580e98 100644 --- a/clippy_lints/src/single_component_path_imports.rs +++ b/clippy_lints/src/single_component_path_imports.rs @@ -1,11 +1,10 @@ -use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::diagnostics::{span_lint_and_help, span_lint_and_sugg}; use clippy_utils::in_macro; -use if_chain::if_chain; -use rustc_ast::{Item, ItemKind, UseTreeKind}; +use rustc_ast::{ptr::P, Crate, Item, ItemKind, ModKind, UseTreeKind}; use rustc_errors::Applicability; use rustc_lint::{EarlyContext, EarlyLintPass}; use rustc_session::{declare_lint_pass, declare_tool_lint}; -use rustc_span::edition::Edition; +use rustc_span::{edition::Edition, symbol::kw, Span, Symbol}; declare_clippy_lint! { /// **What it does:** Checking for imports with single component use path. @@ -38,26 +37,120 @@ declare_clippy_lint! { declare_lint_pass!(SingleComponentPathImports => [SINGLE_COMPONENT_PATH_IMPORTS]); impl EarlyLintPass for SingleComponentPathImports { - fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) { - if_chain! { - if !in_macro(item.span); - if cx.sess.opts.edition >= Edition::Edition2018; - if !item.vis.kind.is_pub(); - if let ItemKind::Use(use_tree) = &item.kind; - if let segments = &use_tree.prefix.segments; - if segments.len() == 1; - if let UseTreeKind::Simple(None, _, _) = use_tree.kind; - then { + fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &Crate) { + if cx.sess.opts.edition < Edition::Edition2018 { + return; + } + check_mod(cx, &krate.items); + } +} + +fn check_mod(cx: &EarlyContext<'_>, items: &[P]) { + // keep track of imports reused with `self` keyword, + // such as `self::crypto_hash` in the example below + // ```rust,ignore + // use self::crypto_hash::{Algorithm, Hasher}; + // ``` + let mut imports_reused_with_self = Vec::new(); + + // keep track of single use statements + // such as `crypto_hash` in the example below + // ```rust,ignore + // use crypto_hash; + // ``` + let mut single_use_usages = Vec::new(); + + for item in items { + track_uses(cx, &item, &mut imports_reused_with_self, &mut single_use_usages); + } + + for single_use in &single_use_usages { + if !imports_reused_with_self.contains(&single_use.0) { + let can_suggest = single_use.2; + if can_suggest { span_lint_and_sugg( cx, SINGLE_COMPONENT_PATH_IMPORTS, - item.span, + single_use.1, "this import is redundant", "remove it entirely", String::new(), - Applicability::MachineApplicable + Applicability::MachineApplicable, + ); + } else { + span_lint_and_help( + cx, + SINGLE_COMPONENT_PATH_IMPORTS, + single_use.1, + "this import is redundant", + None, + "remove this import", ); } } } } + +fn track_uses( + cx: &EarlyContext<'_>, + item: &Item, + imports_reused_with_self: &mut Vec, + single_use_usages: &mut Vec<(Symbol, Span, bool)>, +) { + if in_macro(item.span) || item.vis.kind.is_pub() { + return; + } + + match &item.kind { + ItemKind::Mod(_, ModKind::Loaded(ref items, ..)) => { + check_mod(cx, &items); + }, + ItemKind::Use(use_tree) => { + let segments = &use_tree.prefix.segments; + + // keep track of `use some_module;` usages + if segments.len() == 1 { + if let UseTreeKind::Simple(None, _, _) = use_tree.kind { + let ident = &segments[0].ident; + single_use_usages.push((ident.name, item.span, true)); + } + return; + } + + 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 { + let segments = &tree.0.prefix.segments; + if segments.len() == 1 { + if let UseTreeKind::Simple(None, _, _) = tree.0.kind { + let ident = &segments[0].ident; + single_use_usages.push((ident.name, tree.0.span, false)); + } + } + } + } + } else { + // keep track of `use self::some_module` usages + if segments[0].ident.name == kw::SelfLower { + // simple case such as `use self::module::SomeStruct` + if segments.len() > 1 { + imports_reused_with_self.push(segments[1].ident.name); + return; + } + + // nested case such as `use self::{module1::Struct1, module2::Struct2}` + if let UseTreeKind::Nested(trees) = &use_tree.kind { + for tree in trees { + let segments = &tree.0.prefix.segments; + if !segments.is_empty() { + imports_reused_with_self.push(segments[0].ident.name); + } + } + } + } + } + }, + _ => {}, + } +} diff --git a/tests/ui/single_component_path_imports.fixed b/tests/ui/single_component_path_imports.fixed index a7a8499b58f00..f66b445b7b6a3 100644 --- a/tests/ui/single_component_path_imports.fixed +++ b/tests/ui/single_component_path_imports.fixed @@ -19,3 +19,16 @@ fn main() { // False positive #5154, shouldn't trigger lint. m!(); } + +mod hello_mod { + + #[allow(dead_code)] + fn hello_mod() {} +} + +mod hi_mod { + use self::regex::{Regex, RegexSet}; + use regex; + #[allow(dead_code)] + fn hi_mod() {} +} diff --git a/tests/ui/single_component_path_imports.rs b/tests/ui/single_component_path_imports.rs index 9a427e90ad3df..09d4865859584 100644 --- a/tests/ui/single_component_path_imports.rs +++ b/tests/ui/single_component_path_imports.rs @@ -19,3 +19,16 @@ fn main() { // False positive #5154, shouldn't trigger lint. m!(); } + +mod hello_mod { + use regex; + #[allow(dead_code)] + fn hello_mod() {} +} + +mod hi_mod { + use self::regex::{Regex, RegexSet}; + use regex; + #[allow(dead_code)] + fn hi_mod() {} +} diff --git a/tests/ui/single_component_path_imports.stderr b/tests/ui/single_component_path_imports.stderr index 519ada0169a6d..7005fa8f125d3 100644 --- a/tests/ui/single_component_path_imports.stderr +++ b/tests/ui/single_component_path_imports.stderr @@ -1,10 +1,16 @@ +error: this import is redundant + --> $DIR/single_component_path_imports.rs:24:5 + | +LL | use regex; + | ^^^^^^^^^^ help: remove it entirely + | + = note: `-D clippy::single-component-path-imports` implied by `-D warnings` + error: this import is redundant --> $DIR/single_component_path_imports.rs:6:1 | LL | use regex; | ^^^^^^^^^^ help: remove it entirely - | - = note: `-D clippy::single-component-path-imports` implied by `-D warnings` -error: aborting due to previous error +error: aborting due to 2 previous errors diff --git a/tests/ui/single_component_path_imports_nested_first.rs b/tests/ui/single_component_path_imports_nested_first.rs new file mode 100644 index 0000000000000..94117061b270d --- /dev/null +++ b/tests/ui/single_component_path_imports_nested_first.rs @@ -0,0 +1,17 @@ +// edition:2018 +#![warn(clippy::single_component_path_imports)] +#![allow(unused_imports)] + +use regex; +use serde as edres; +pub use serde; + +fn main() { + regex::Regex::new(r"^\d{4}-\d{2}-\d{2}$").unwrap(); +} + +mod root_nested_use_mod { + use {regex, serde}; + #[allow(dead_code)] + fn root_nested_use_mod() {} +} diff --git a/tests/ui/single_component_path_imports_nested_first.stderr b/tests/ui/single_component_path_imports_nested_first.stderr new file mode 100644 index 0000000000000..0c3256c1ce43a --- /dev/null +++ b/tests/ui/single_component_path_imports_nested_first.stderr @@ -0,0 +1,25 @@ +error: this import is redundant + --> $DIR/single_component_path_imports_nested_first.rs:14:10 + | +LL | use {regex, serde}; + | ^^^^^ + | + = note: `-D clippy::single-component-path-imports` implied by `-D warnings` + = help: remove this import + +error: this import is redundant + --> $DIR/single_component_path_imports_nested_first.rs:14:17 + | +LL | use {regex, serde}; + | ^^^^^ + | + = help: remove this import + +error: this import is redundant + --> $DIR/single_component_path_imports_nested_first.rs:5:1 + | +LL | use regex; + | ^^^^^^^^^^ help: remove it entirely + +error: aborting due to 3 previous errors + diff --git a/tests/ui/single_component_path_imports_self_after.rs b/tests/ui/single_component_path_imports_self_after.rs new file mode 100644 index 0000000000000..94319ade0ac4b --- /dev/null +++ b/tests/ui/single_component_path_imports_self_after.rs @@ -0,0 +1,16 @@ +// edition:2018 +#![warn(clippy::single_component_path_imports)] +#![allow(unused_imports)] + +use self::regex::{Regex as xeger, RegexSet as tesxeger}; +pub use self::{ + regex::{Regex, RegexSet}, + some_mod::SomeType, +}; +use regex; + +mod some_mod { + pub struct SomeType; +} + +fn main() {} diff --git a/tests/ui/single_component_path_imports_self_before.rs b/tests/ui/single_component_path_imports_self_before.rs new file mode 100644 index 0000000000000..c7437b234566a --- /dev/null +++ b/tests/ui/single_component_path_imports_self_before.rs @@ -0,0 +1,17 @@ +// edition:2018 +#![warn(clippy::single_component_path_imports)] +#![allow(unused_imports)] + +use regex; + +use self::regex::{Regex as xeger, RegexSet as tesxeger}; +pub use self::{ + regex::{Regex, RegexSet}, + some_mod::SomeType, +}; + +mod some_mod { + pub struct SomeType; +} + +fn main() {}