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https://github.com/rust-lang/rust-clippy
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Implementation of the const_static_lifetime
lint.
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commit
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4 changed files with 120 additions and 2 deletions
82
clippy_lints/src/const_static_lifetime.rs
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82
clippy_lints/src/const_static_lifetime.rs
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@ -0,0 +1,82 @@
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use syntax::ast::{Item, ItemKind, TyKind, Ty};
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use rustc::lint::{LintPass, EarlyLintPass, LintArray, EarlyContext};
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use utils::{span_help_and_lint, in_macro};
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/// **What it does:** Checks for constants with an explicit `'static` lifetime.
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///
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/// **Why is this bad?** Adding `'static` to every reference can create very complicated types.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// const FOO: &'static [(&'static str, &'static str, fn(&Bar) -> bool)] = &[..]
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/// ```
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/// This code can be rewritten as
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/// ```rust
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/// const FOO: &[(&str, &str, fn(&Bar) -> bool)] = &[...]
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/// ```
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declare_lint! {
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pub CONST_STATIC_LIFETIME,
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Warn,
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"Using explicit `'static` lifetime for constants when elision rules would allow omitting them."
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}
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pub struct StaticConst;
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impl LintPass for StaticConst {
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fn get_lints(&self) -> LintArray {
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lint_array!(CONST_STATIC_LIFETIME)
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}
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}
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impl StaticConst {
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// Recursively visit types
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fn visit_type(&mut self, ty: &Ty, cx: &EarlyContext) {
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match ty.node {
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// Be carefull of nested structures (arrays and tuples)
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TyKind::Array(ref ty, _) => {
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println!("array");
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self.visit_type(&*ty, cx);
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},
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TyKind::Tup(ref tup) => {
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for tup_ty in tup {
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self.visit_type(&*tup_ty, cx);
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}
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},
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// This is what we are looking for !
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TyKind::Rptr(ref optional_lifetime, ref borrow_type) => {
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// Match the 'static lifetime
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if let Some(lifetime) = *optional_lifetime {
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if let TyKind::Path(_, _) = borrow_type.ty.node {
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// Verify that the path is a str
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if lifetime.ident.name == "'static" {
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span_help_and_lint(cx,
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CONST_STATIC_LIFETIME,
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lifetime.span,
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"Constants have by default a `'static` lifetime",
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"consider removing `'static`");
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}
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}
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}
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self.visit_type(&*borrow_type.ty, cx);
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},
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TyKind::Slice(ref ty) => {
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self.visit_type(&ty, cx);
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},
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_ => {},
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}
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}
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}
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impl EarlyLintPass for StaticConst {
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fn check_item(&mut self, cx: &EarlyContext, item: &Item) {
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if !in_macro(item.span) {
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// Match only constants...
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if let ItemKind::Const(ref var_type, _) = item.node {
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self.visit_type(var_type, cx);
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}
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}
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}
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}
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@ -76,6 +76,7 @@ pub mod block_in_if_condition;
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pub mod booleans;
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pub mod bytecount;
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pub mod collapsible_if;
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pub mod const_static_lifetime;
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pub mod copies;
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pub mod cyclomatic_complexity;
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pub mod derive;
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@ -339,6 +340,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
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reg.register_late_lint_pass(box invalid_ref::InvalidRef);
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reg.register_late_lint_pass(box identity_conversion::IdentityConversion::default());
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reg.register_late_lint_pass(box types::ImplicitHasher);
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reg.register_early_lint_pass(box const_static_lifetime::StaticConst);
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reg.register_lint_group("clippy_restrictions", vec![
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arithmetic::FLOAT_ARITHMETIC,
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@ -349,6 +351,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
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reg.register_lint_group("clippy_pedantic", vec![
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booleans::NONMINIMAL_BOOL,
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const_static_lifetime::CONST_STATIC_LIFETIME,
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empty_enum::EMPTY_ENUM,
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enum_glob_use::ENUM_GLOB_USE,
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enum_variants::PUB_ENUM_VARIANT_NAMES,
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33
tests/ui/const_static_lifetime.rs
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33
tests/ui/const_static_lifetime.rs
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#![feature(plugin)]
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#[derive(Debug)]
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struct Foo {}
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const VAR_ONE: &'static str = "Test constant #1"; // ERROR Consider removing 'static.
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const VAR_TWO: &str = "Test constant #2"; // This line should not raise a warning.
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const VAR_THREE: &[&'static str] = &["one", "two"]; // ERROR Consider removing 'static
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const VAR_FOUR: (&str, (&str, &'static str), &'static str) = ("on", ("th", "th"), "on"); // ERROR Consider removing 'static
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const VAR_FIVE: &'static [&[&'static str]] = &[&["test"], &["other one"]]; // ERROR Consider removing 'static
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const VAR_SIX: &'static u8 = &5;
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const VAR_SEVEN: &[&(&str, &'static [&'static str])] = &[&("one", &["other one"])];
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const VAR_HEIGHT: &'static Foo = &Foo {};
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fn main() {
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let false_positive: &'static str = "test";
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println!("{}", VAR_ONE);
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println!("{}", VAR_TWO);
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println!("{:?}", VAR_THREE);
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println!("{:?}", VAR_FOUR);
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println!("{:?}", VAR_FIVE);
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println!("{:?}", VAR_SIX);
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println!("{:?}", VAR_SEVEN);
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println!("{:?}", VAR_HEIGHT);
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println!("{}", false_positive);
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}
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@ -9,8 +9,8 @@ extern crate regex;
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use regex::{Regex, RegexSet, RegexBuilder};
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use regex::bytes::{Regex as BRegex, RegexSet as BRegexSet, RegexBuilder as BRegexBuilder};
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const OPENING_PAREN : &'static str = "(";
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const NOT_A_REAL_REGEX : &'static str = "foobar";
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const OPENING_PAREN: &str = "(";
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const NOT_A_REAL_REGEX: &str = "foobar";
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fn syntax_error() {
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let pipe_in_wrong_position = Regex::new("|");
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