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

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use crate::utils::{
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is_expn_of, match_def_path, match_type, method_calls, paths, span_help_and_lint, span_lint, span_lint_and_sugg,
walk_ptrs_ty,
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};
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use if_chain::if_chain;
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use rustc::hir::map::Map;
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use rustc::lint::{EarlyContext, EarlyLintPass, LateContext, LateLintPass};
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
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use rustc_errors::Applicability;
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use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
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use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
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use rustc_hir::*;
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use rustc_session::declare_tool_lint;
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use rustc_session::{declare_lint_pass, impl_lint_pass};
use rustc_span::source_map::Span;
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use rustc_span::symbol::SymbolStr;
use syntax::ast;
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use syntax::ast::{Crate as AstCrate, ItemKind, Name};
use syntax::visit::FnKind;
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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.
///
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/// **Known problems:** Only checks for lints associated using the
/// `declare_lint_pass!`, `impl_lint_pass!`, and `lint_array!` macros.
///
/// **Example:**
/// ```rust,ignore
/// declare_lint! { pub LINT_1, ... }
/// declare_lint! { pub LINT_2, ... }
/// declare_lint! { pub FORGOTTEN_LINT, ... }
/// // ...
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/// declare_lint_pass!(Pass => [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 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,ignore
/// cx.span_lint(LINT_NAME, "message");
/// ```
///
/// Good:
/// ```rust,ignore
/// 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"
}
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declare_clippy_lint! {
/// **What it does:** Checks for calls to `cx.outer().expn_data()` and suggests to use
/// the `cx.outer_expn_data()`
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///
/// **Why is this bad?** `cx.outer_expn_data()` is faster and more concise.
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///
/// **Known problems:** None.
///
/// **Example:**
/// Bad:
/// ```rust,ignore
/// expr.span.ctxt().outer().expn_data()
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/// ```
///
/// Good:
/// ```rust,ignore
/// expr.span.ctxt().outer_expn_data()
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/// ```
pub OUTER_EXPN_EXPN_DATA,
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internal,
"using `cx.outer_expn().expn_data()` instead of `cx.outer_expn_data()`"
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}
declare_clippy_lint! {
/// **What it does:** Not an actual lint. This lint is only meant for testing our customized internal compiler
/// error message by calling `panic`.
///
/// **Why is this bad?** ICE in large quantities can damage your teeth
///
/// **Known problems:** None
///
/// **Example:**
/// Bad:
/// ```rust,ignore
/// 🍦🍦🍦🍦🍦
/// ```
pub PRODUCE_ICE,
internal,
"this message should not appear anywhere as we ICE before and don't emit the lint"
}
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declare_lint_pass!(ClippyLintsInternal => [CLIPPY_LINTS_INTERNAL]);
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impl EarlyLintPass for ClippyLintsInternal {
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fn check_crate(&mut self, cx: &EarlyContext<'_>, krate: &AstCrate) {
if let Some(utils) = krate
.module
.items
.iter()
.find(|item| item.ident.name.as_str() == "utils")
{
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if let ItemKind::Mod(ref utils_mod) = utils.kind {
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if let Some(paths) = utils_mod.items.iter().find(|item| item.ident.name.as_str() == "paths") {
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if let ItemKind::Mod(ref paths_mod) = paths.kind {
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let mut last_name: Option<SymbolStr> = None;
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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>,
}
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impl_lint_pass!(LintWithoutLintPass => [LINT_WITHOUT_LINT_PASS]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LintWithoutLintPass {
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fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item<'_>) {
if let hir::ItemKind::Static(ref ty, Mutability::Not, _) = item.kind {
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if is_lint_ref_type(cx, ty) {
self.declared_lints.insert(item.ident.name, item.span);
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}
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} else if is_expn_of(item.span, "impl_lint_pass").is_some()
|| is_expn_of(item.span, "declare_lint_pass").is_some()
{
if let hir::ItemKind::Impl(.., None, _, ref impl_item_refs) = item.kind {
let mut collector = LintCollector {
output: &mut self.registered_lints,
cx,
};
let body_id = cx.tcx.hir().body_owned_by(
impl_item_refs
.iter()
.find(|iiref| iiref.ident.as_str() == "get_lints")
.expect("LintPass needs to implement get_lints")
.id
.hir_id,
);
collector.visit_expr(&cx.tcx.hir().body(body_id).value);
}
}
}
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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().outer_expn_data().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: Mutability::Not,
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},
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) = ty.kind
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{
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if let TyKind::Path(ref path) = inner.kind {
if let Res::Def(DefKind::Struct, def_id) = cx.tables.qpath_res(path, inner.hir_id) {
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return match_def_path(cx, def_id, &paths::LINT);
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}
}
}
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false
}
struct LintCollector<'a, 'tcx> {
output: &'a mut FxHashSet<Name>,
cx: &'a LateContext<'a, 'tcx>,
}
impl<'a, 'tcx> Visitor<'tcx> for LintCollector<'a, 'tcx> {
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type Map = Map<'tcx>;
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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);
}
}
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fn nested_visit_map(&mut self) -> NestedVisitorMap<'_, Self::Map> {
NestedVisitorMap::All(&self.cx.tcx.hir())
}
}
#[derive(Clone, Default)]
pub struct CompilerLintFunctions {
map: FxHashMap<&'static str, &'static str>,
}
impl CompilerLintFunctions {
#[must_use]
pub fn new() -> Self {
let mut map = FxHashMap::default();
map.insert("span_lint", "utils::span_lint");
map.insert("struct_span_lint", "utils::span_lint");
map.insert("lint", "utils::span_lint");
map.insert("span_lint_note", "utils::span_note_and_lint");
map.insert("span_lint_help", "utils::span_help_and_lint");
Self { map }
}
}
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impl_lint_pass!(CompilerLintFunctions => [COMPILER_LINT_FUNCTIONS]);
impl<'a, 'tcx> LateLintPass<'a, 'tcx> for CompilerLintFunctions {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_>) {
if_chain! {
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if let ExprKind::MethodCall(ref path, _, ref args) = expr.kind;
let fn_name = path.ident;
if let Some(sugg) = self.map.get(&*fn_name.as_str());
let ty = walk_ptrs_ty(cx.tables.expr_ty(&args[0]));
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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),
);
}
}
}
}
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declare_lint_pass!(OuterExpnDataPass => [OUTER_EXPN_EXPN_DATA]);
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for OuterExpnDataPass {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx hir::Expr<'_>) {
let (method_names, arg_lists, spans) = method_calls(expr, 2);
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let method_names: Vec<SymbolStr> = method_names.iter().map(|s| s.as_str()).collect();
let method_names: Vec<&str> = method_names.iter().map(|s| &**s).collect();
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if_chain! {
if let ["expn_data", "outer_expn"] = method_names.as_slice();
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let args = arg_lists[1];
if args.len() == 1;
let self_arg = &args[0];
let self_ty = walk_ptrs_ty(cx.tables.expr_ty(self_arg));
if match_type(cx, self_ty, &paths::SYNTAX_CONTEXT);
then {
span_lint_and_sugg(
cx,
OUTER_EXPN_EXPN_DATA,
spans[1].with_hi(expr.span.hi()),
"usage of `outer_expn().expn_data()`",
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"try",
"outer_expn_data()".to_string(),
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Applicability::MachineApplicable,
);
}
}
}
}
declare_lint_pass!(ProduceIce => [PRODUCE_ICE]);
impl EarlyLintPass for ProduceIce {
fn check_fn(&mut self, _: &EarlyContext<'_>, fn_kind: FnKind<'_>, _: &ast::FnDecl, _: Span, _: ast::NodeId) {
if is_trigger_fn(fn_kind) {
panic!("Testing the ICE message");
}
}
}
fn is_trigger_fn(fn_kind: FnKind<'_>) -> bool {
match fn_kind {
FnKind::ItemFn(ident, ..) | FnKind::Method(ident, ..) => {
ident.name.as_str() == "it_looks_like_you_are_trying_to_kill_clippy"
},
FnKind::Closure(..) => false,
}
}