diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_lints.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.register_restriction.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/lib.rs | 2 | ||||
| -rw-r--r-- | clippy_lints/src/single_char_lifetime_names.rs | 63 | ||||
| -rw-r--r-- | tests/ui/single_char_lifetime_names.rs | 43 | ||||
| -rw-r--r-- | tests/ui/single_char_lifetime_names.stderr | 43 |
7 files changed, 154 insertions, 0 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index 27bac4718b6..83fd8396bc7 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3253,6 +3253,7 @@ Released 2018-09-13 [`should_implement_trait`]: https://rust-lang.github.io/rust-clippy/master/index.html#should_implement_trait [`similar_names`]: https://rust-lang.github.io/rust-clippy/master/index.html#similar_names [`single_char_add_str`]: https://rust-lang.github.io/rust-clippy/master/index.html#single_char_add_str +[`single_char_lifetime_names`]: https://rust-lang.github.io/rust-clippy/master/index.html#single_char_lifetime_names [`single_char_pattern`]: https://rust-lang.github.io/rust-clippy/master/index.html#single_char_pattern [`single_component_path_imports`]: https://rust-lang.github.io/rust-clippy/master/index.html#single_component_path_imports [`single_element_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#single_element_loop diff --git a/clippy_lints/src/lib.register_lints.rs b/clippy_lints/src/lib.register_lints.rs index 002122793f3..f9241d943b2 100644 --- a/clippy_lints/src/lib.register_lints.rs +++ b/clippy_lints/src/lib.register_lints.rs @@ -435,6 +435,7 @@ store.register_lints(&[ shadow::SHADOW_REUSE, shadow::SHADOW_SAME, shadow::SHADOW_UNRELATED, + single_char_lifetime_names::SINGLE_CHAR_LIFETIME_NAMES, single_component_path_imports::SINGLE_COMPONENT_PATH_IMPORTS, size_of_in_element_count::SIZE_OF_IN_ELEMENT_COUNT, slow_vector_initialization::SLOW_VECTOR_INITIALIZATION, diff --git a/clippy_lints/src/lib.register_restriction.rs b/clippy_lints/src/lib.register_restriction.rs index eab389a9bd8..e7e2798da7d 100644 --- a/clippy_lints/src/lib.register_restriction.rs +++ b/clippy_lints/src/lib.register_restriction.rs @@ -54,6 +54,7 @@ store.register_group(true, "clippy::restriction", Some("clippy_restriction"), ve LintId::of(shadow::SHADOW_REUSE), LintId::of(shadow::SHADOW_SAME), LintId::of(shadow::SHADOW_UNRELATED), + LintId::of(single_char_lifetime_names::SINGLE_CHAR_LIFETIME_NAMES), LintId::of(strings::STRING_ADD), LintId::of(strings::STRING_SLICE), LintId::of(strings::STRING_TO_STRING), diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs index d4687a1e287..c31acb5f4ef 100644 --- a/clippy_lints/src/lib.rs +++ b/clippy_lints/src/lib.rs @@ -351,6 +351,7 @@ mod self_named_constructors; mod semicolon_if_nothing_returned; mod serde_api; mod shadow; +mod single_char_lifetime_names; mod single_component_path_imports; mod size_of_in_element_count; mod slow_vector_initialization; @@ -858,6 +859,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf: store.register_late_pass(|| Box::new(needless_late_init::NeedlessLateInit)); store.register_late_pass(|| Box::new(return_self_not_must_use::ReturnSelfNotMustUse)); store.register_late_pass(|| Box::new(init_numbered_fields::NumberedFields)); + store.register_early_pass(|| Box::new(single_char_lifetime_names::SingleCharLifetimeNames)); // add lints here, do not remove this comment, it's used in `new_lint` } diff --git a/clippy_lints/src/single_char_lifetime_names.rs b/clippy_lints/src/single_char_lifetime_names.rs new file mode 100644 index 00000000000..ee82666b5af --- /dev/null +++ b/clippy_lints/src/single_char_lifetime_names.rs @@ -0,0 +1,63 @@ +use clippy_utils::diagnostics::span_lint_and_help; +use rustc_ast::ast::{GenericParam, GenericParamKind}; +use rustc_lint::{EarlyContext, EarlyLintPass}; +use rustc_middle::lint::in_external_macro; +use rustc_session::{declare_lint_pass, declare_tool_lint}; + +declare_clippy_lint! { + /// ### What it does + /// Checks for lifetimes with names which are one character + /// long. + /// + /// ### Why is this bad? + /// A single character is likely not enough to express the + /// purpose of a lifetime. Using a longer name can make code + /// easier to understand, especially for those who are new to + /// Rust. + /// + /// ### Known problems + /// Rust programmers and learning resources tend to use single + /// character lifetimes, so this lint is at odds with the + /// ecosystem at large. In addition, the lifetime's purpose may + /// be obvious or, rarely, expressible in one character. + /// + /// ### Example + /// ```rust + /// struct DiagnosticCtx<'a> { + /// source: &'a str, + /// } + /// ``` + /// Use instead: + /// ```rust + /// struct DiagnosticCtx<'src> { + /// source: &'src str, + /// } + /// ``` + #[clippy::version = "1.59.0"] + pub SINGLE_CHAR_LIFETIME_NAMES, + restriction, + "warns against single-character lifetime names" +} + +declare_lint_pass!(SingleCharLifetimeNames => [SINGLE_CHAR_LIFETIME_NAMES]); + +impl EarlyLintPass for SingleCharLifetimeNames { + fn check_generic_param(&mut self, ctx: &EarlyContext<'_>, param: &GenericParam) { + if in_external_macro(ctx.sess, param.ident.span) { + return; + } + + if let GenericParamKind::Lifetime = param.kind { + if !param.is_placeholder && param.ident.as_str().len() <= 2 { + span_lint_and_help( + ctx, + SINGLE_CHAR_LIFETIME_NAMES, + param.ident.span, + "single-character lifetime names are likely uninformative", + None, + "use a more informative name", + ); + } + } + } +} diff --git a/tests/ui/single_char_lifetime_names.rs b/tests/ui/single_char_lifetime_names.rs new file mode 100644 index 00000000000..261d8bc7260 --- /dev/null +++ b/tests/ui/single_char_lifetime_names.rs @@ -0,0 +1,43 @@ +#![warn(clippy::single_char_lifetime_names)] + +// Lifetimes should only be linted when they're introduced +struct DiagnosticCtx<'a, 'b> +where + 'a: 'b, +{ + _source: &'a str, + _unit: &'b (), +} + +// Only the lifetimes on the `impl`'s generics should be linted +impl<'a, 'b> DiagnosticCtx<'a, 'b> { + fn new(source: &'a str, unit: &'b ()) -> DiagnosticCtx<'a, 'b> { + Self { + _source: source, + _unit: unit, + } + } +} + +// No lifetimes should be linted here +impl<'src, 'unit> DiagnosticCtx<'src, 'unit> { + fn new_pass(source: &'src str, unit: &'unit ()) -> DiagnosticCtx<'src, 'unit> { + Self { + _source: source, + _unit: unit, + } + } +} + +// Only 'a should be linted here +fn split_once<'a>(base: &'a str, other: &'_ str) -> (&'a str, Option<&'a str>) { + base.split_once(other) + .map(|(left, right)| (left, Some(right))) + .unwrap_or((base, None)) +} + +fn main() { + let src = "loop {}"; + let unit = (); + DiagnosticCtx::new(src, &unit); +} diff --git a/tests/ui/single_char_lifetime_names.stderr b/tests/ui/single_char_lifetime_names.stderr new file mode 100644 index 00000000000..013b64f46a8 --- /dev/null +++ b/tests/ui/single_char_lifetime_names.stderr @@ -0,0 +1,43 @@ +error: single-character lifetime names are likely uninformative + --> $DIR/single_char_lifetime_names.rs:4:22 + | +LL | struct DiagnosticCtx<'a, 'b> + | ^^ + | + = note: `-D clippy::single-char-lifetime-names` implied by `-D warnings` + = help: use a more informative name + +error: single-character lifetime names are likely uninformative + --> $DIR/single_char_lifetime_names.rs:4:26 + | +LL | struct DiagnosticCtx<'a, 'b> + | ^^ + | + = help: use a more informative name + +error: single-character lifetime names are likely uninformative + --> $DIR/single_char_lifetime_names.rs:13:6 + | +LL | impl<'a, 'b> DiagnosticCtx<'a, 'b> { + | ^^ + | + = help: use a more informative name + +error: single-character lifetime names are likely uninformative + --> $DIR/single_char_lifetime_names.rs:13:10 + | +LL | impl<'a, 'b> DiagnosticCtx<'a, 'b> { + | ^^ + | + = help: use a more informative name + +error: single-character lifetime names are likely uninformative + --> $DIR/single_char_lifetime_names.rs:33:15 + | +LL | fn split_once<'a>(base: &'a str, other: &'_ str) -> (&'a str, Option<&'a str>) { + | ^^ + | + = help: use a more informative name + +error: aborting due to 5 previous errors + |