rust-clippy/clippy_lints/src/utils/internal_lints.rs

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use crate::utils::{
match_def_path, match_type, paths, span_help_and_lint, span_lint, span_lint_and_sugg, walk_ptrs_ty,
};
use if_chain::if_chain;
use rustc::hir;
use rustc::hir::def::Def;
use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
use rustc::hir::*;
use rustc::lint::{EarlyContext, EarlyLintPass, LateContext, LateLintPass, LintArray, LintPass};
use rustc::{declare_tool_lint, lint_array};
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_errors::Applicability;
use syntax::ast::{Crate as AstCrate, Ident, ItemKind, Name};
use syntax::source_map::Span;
use syntax::symbol::LocalInternedString;
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declare_clippy_lint! {
/// **What it does:** Checks for various things we like to keep tidy in clippy.
///
/// **Why is this bad?** We like to pretend we're an example of tidy code.
///
/// **Known problems:** None.
///
/// **Example:** Wrong ordering of the util::paths constants.
pub CLIPPY_LINTS_INTERNAL,
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internal,
"various things that will negatively affect your clippy experience"
}
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declare_clippy_lint! {
/// **What it does:** Ensures every lint is associated to a `LintPass`.
///
/// **Why is this bad?** The compiler only knows lints via a `LintPass`. Without
/// putting a lint to a `LintPass::get_lints()`'s return, the compiler will not
/// know the name of the lint.
///
/// **Known problems:** Only checks for lints associated using the `lint_array!`
/// macro.
///
/// **Example:**
/// ```rust
/// declare_lint! { pub LINT_1, ... }
/// declare_lint! { pub LINT_2, ... }
/// declare_lint! { pub FORGOTTEN_LINT, ... }
/// // ...
/// pub struct Pass;
/// impl LintPass for Pass {
/// fn get_lints(&self) -> LintArray {
/// lint_array![LINT_1, LINT_2]
/// // missing FORGOTTEN_LINT
/// }
/// }
/// ```
pub LINT_WITHOUT_LINT_PASS,
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internal,
"declaring a lint without associating it in a LintPass"
}
declare_clippy_lint! {
/// **What it does:** Checks for the presence of the default hash types "HashMap" or "HashSet"
/// and recommends the FxHash* variants.
///
/// **Why is this bad?** The FxHash variants have better performance
/// and we don't need any collision prevention in clippy.
pub DEFAULT_HASH_TYPES,
internal,
"forbid HashMap and HashSet and suggest the FxHash* variants"
}
declare_clippy_lint! {
/// **What it does:** Checks for calls to `cx.span_lint*` and suggests to use the `utils::*`
/// variant of the function.
///
/// **Why is this bad?** The `utils::*` variants also add a link to the Clippy documentation to the
/// warning/error messages.
///
/// **Known problems:** None.
///
/// **Example:**
/// Bad:
/// ```rust
/// cx.span_lint(LINT_NAME, "message");
/// ```
///
/// Good:
/// ```rust
/// utils::span_lint(cx, LINT_NAME, "message");
/// ```
pub COMPILER_LINT_FUNCTIONS,
internal,
"usage of the lint functions of the compiler instead of the utils::* variant"
}
#[derive(Copy, Clone)]
pub struct Clippy;
impl LintPass for Clippy {
fn get_lints(&self) -> LintArray {
lint_array!(CLIPPY_LINTS_INTERNAL)
}
fn name(&self) -> &'static str {
"ClippyLintsInternal"
}
}
impl EarlyLintPass for Clippy {
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fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &AstCrate) {
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if let Some(utils) = krate.module.items.iter().find(|item| item.ident.name == "utils") {
if let ItemKind::Mod(ref utils_mod) = utils.node {
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if let Some(paths) = utils_mod.items.iter().find(|item| item.ident.name == "paths") {
if let ItemKind::Mod(ref paths_mod) = paths.node {
let mut last_name: Option<LocalInternedString> = None;
for item in &paths_mod.items {
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let name = item.ident.as_str();
if let Some(ref last_name) = last_name {
if **last_name > *name {
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span_lint(
cx,
CLIPPY_LINTS_INTERNAL,
item.span,
"this constant should be before the previous constant due to lexical \
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ordering",
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);
}
}
last_name = Some(name);
}
}
}
}
}
}
}
#[derive(Clone, Debug, Default)]
pub struct LintWithoutLintPass {
declared_lints: FxHashMap<Name, Span>,
registered_lints: FxHashSet<Name>,
}
impl LintPass for LintWithoutLintPass {
fn get_lints(&self) -> LintArray {
lint_array!(LINT_WITHOUT_LINT_PASS)
}
fn name(&self) -> &'static str {
"LintWithoutLintPass"
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LintWithoutLintPass {
fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
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if let hir::ItemKind::Static(ref ty, MutImmutable, _) = item.node {
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if is_lint_ref_type(cx, ty) {
self.declared_lints.insert(item.ident.name, item.span);
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}
} else if let hir::ItemKind::Impl(.., Some(ref trait_ref), _, ref impl_item_refs) = item.node {
if_chain! {
if let hir::TraitRef{path, ..} = trait_ref;
if let Def::Trait(def_id) = path.def;
if match_def_path(cx.tcx, def_id, &paths::LINT_PASS);
then {
let mut collector = LintCollector {
output: &mut self.registered_lints,
cx,
};
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let body_id = cx.tcx.hir().body_owned_by(impl_item_refs[0].id.hir_id);
collector.visit_expr(&cx.tcx.hir().body(body_id).value);
}
}
}
}
fn check_crate_post(&mut self, cx: &LateContext<'a, 'tcx>, _: &'tcx Crate) {
for (lint_name, &lint_span) in &self.declared_lints {
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// When using the `declare_tool_lint!` macro, the original `lint_span`'s
// file points to "<rustc macros>".
// `compiletest-rs` thinks that's an error in a different file and
// just ignores it. This causes the test in compile-fail/lint_pass
// not able to capture the error.
// Therefore, we need to climb the macro expansion tree and find the
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// actual span that invoked `declare_tool_lint!`:
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let lint_span = lint_span
.ctxt()
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.outer()
.expn_info()
.map(|ei| ei.call_site)
.expect("unable to get call_site");
if !self.registered_lints.contains(lint_name) {
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span_lint(
cx,
LINT_WITHOUT_LINT_PASS,
lint_span,
&format!("the lint `{}` is not added to any `LintPass`", lint_name),
);
}
}
}
}
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fn is_lint_ref_type<'tcx>(cx: &LateContext<'_, 'tcx>, ty: &Ty) -> bool {
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if let TyKind::Rptr(
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_,
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MutTy {
ty: ref inner,
mutbl: MutImmutable,
},
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) = ty.node
{
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if let TyKind::Path(ref path) = inner.node {
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if let Def::Struct(def_id) = cx.tables.qpath_def(path, inner.hir_id) {
return match_def_path(cx.tcx, def_id, &paths::LINT);
}
}
}
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false
}
struct LintCollector<'a, 'tcx: 'a> {
output: &'a mut FxHashSet<Name>,
cx: &'a LateContext<'a, 'tcx>,
}
impl<'a, 'tcx: 'a> Visitor<'tcx> for LintCollector<'a, 'tcx> {
fn visit_expr(&mut self, expr: &'tcx Expr) {
walk_expr(self, expr);
}
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fn visit_path(&mut self, path: &'tcx Path, _: HirId) {
if path.segments.len() == 1 {
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self.output.insert(path.segments[0].ident.name);
}
}
fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
NestedVisitorMap::All(&self.cx.tcx.hir())
}
}
pub struct DefaultHashTypes {
map: FxHashMap<String, String>,
}
impl DefaultHashTypes {
pub fn default() -> Self {
let mut map = FxHashMap::default();
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map.insert("HashMap".to_string(), "FxHashMap".to_string());
map.insert("HashSet".to_string(), "FxHashSet".to_string());
Self { map }
}
}
impl LintPass for DefaultHashTypes {
fn get_lints(&self) -> LintArray {
lint_array!(DEFAULT_HASH_TYPES)
}
fn name(&self) -> &'static str {
"DefaultHashType"
}
}
impl EarlyLintPass for DefaultHashTypes {
fn check_ident(&mut self, cx: &EarlyContext<'_>, ident: Ident) {
let ident_string = ident.to_string();
if let Some(replace) = self.map.get(&ident_string) {
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let msg = format!(
"Prefer {} over {}, it has better performance \
and we don't need any collision prevention in clippy",
replace, ident_string
);
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span_lint_and_sugg(
cx,
DEFAULT_HASH_TYPES,
ident.span,
&msg,
"use",
replace.to_string(),
Applicability::MaybeIncorrect, // FxHashMap, ... needs another import
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);
}
}
}
#[derive(Clone, Default)]
pub struct CompilerLintFunctions {
map: FxHashMap<String, String>,
}
impl CompilerLintFunctions {
pub fn new() -> Self {
let mut map = FxHashMap::default();
map.insert("span_lint".to_string(), "utils::span_lint".to_string());
map.insert("struct_span_lint".to_string(), "utils::span_lint".to_string());
map.insert("lint".to_string(), "utils::span_lint".to_string());
map.insert("span_lint_note".to_string(), "utils::span_note_and_lint".to_string());
map.insert("span_lint_help".to_string(), "utils::span_help_and_lint".to_string());
Self { map }
}
}
impl LintPass for CompilerLintFunctions {
fn get_lints(&self) -> LintArray {
lint_array!(COMPILER_LINT_FUNCTIONS)
}
fn name(&self) -> &'static str {
"CompileLintFunctions"
}
}
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CompilerLintFunctions {
fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
if_chain! {
if let ExprKind::MethodCall(ref path, _, ref args) = expr.node;
let fn_name = path.ident.as_str().to_string();
if let Some(sugg) = self.map.get(&fn_name);
let ty = walk_ptrs_ty(cx.tables.expr_ty(&args[0]));
if match_type(cx, ty, &paths::EARLY_CONTEXT)
|| match_type(cx, ty, &paths::LATE_CONTEXT);
then {
span_help_and_lint(
cx,
COMPILER_LINT_FUNCTIONS,
path.ident.span,
"usage of a compiler lint function",
&format!("Please use the Clippy variant of this function: `{}`", sugg),
);
}
}
}
}