src/tools/clippy/clippy_lints/src/utils/internal_lints.rs

   1 use rustc::lint::*;
   2 use rustc::hir::*;
   3 use rustc::hir::intravisit::{walk_expr, NestedVisitorMap, Visitor};
   4 use utils::{match_qpath, paths, span_lint};
   5 use syntax::symbol::InternedString;
   6 use syntax::ast::{Crate as AstCrate, ItemKind, Name, NodeId};
   7 use syntax::codemap::Span;
   8 use std::collections::{HashMap, HashSet};
   9
  10
  11 /// **What it does:** Checks for various things we like to keep tidy in clippy.
  12 ///
  13 /// **Why is this bad?** We like to pretend we're an example of tidy code.
  14 ///
  15 /// **Known problems:** None.
  16 ///
  17 /// **Example:** Wrong ordering of the util::paths constants.
  18 declare_lint! {
  19     pub CLIPPY_LINTS_INTERNAL,
  20     Allow,
  21     "various things that will negatively affect your clippy experience"
  22 }
  23
  24
  25 /// **What it does:** Ensures every lint is associated to a `LintPass`.
  26 ///
  27 /// **Why is this bad?** The compiler only knows lints via a `LintPass`. Without
  28 /// putting a lint to a `LintPass::get_lints()`'s return, the compiler will not
  29 /// know the name of the lint.
  30 ///
  31 /// **Known problems:** Only checks for lints associated using the `lint_array!`
  32 /// macro.
  33 ///
  34 /// **Example:**
  35 /// ```rust
  36 /// declare_lint! { pub LINT_1, ... }
  37 /// declare_lint! { pub LINT_2, ... }
  38 /// declare_lint! { pub FORGOTTEN_LINT, ... }
  39 /// // ...
  40 /// pub struct Pass;
  41 /// impl LintPass for Pass {
  42 ///     fn get_lints(&self) -> LintArray {
  43 ///         lint_array![LINT_1, LINT_2]
  44 ///         // missing FORGOTTEN_LINT
  45 ///     }
  46 /// }
  47 /// ```
  48 declare_lint! {
  49     pub LINT_WITHOUT_LINT_PASS,
  50     Warn,
  51     "declaring a lint without associating it in a LintPass"
  52 }
  53
  54
  55 #[derive(Copy, Clone)]
  56 pub struct Clippy;
  57
  58 impl LintPass for Clippy {
  59     fn get_lints(&self) -> LintArray {
  60         lint_array!(CLIPPY_LINTS_INTERNAL)
  61     }
  62 }
  63
  64 impl EarlyLintPass for Clippy {
  65     fn check_crate(&mut self, cx: &EarlyContext, krate: &AstCrate) {
  66         if let Some(utils) = krate
  67             .module
  68             .items
  69             .iter()
  70             .find(|item| item.ident.name == "utils")
  71         {
  72             if let ItemKind::Mod(ref utils_mod) = utils.node {
  73                 if let Some(paths) = utils_mod
  74                     .items
  75                     .iter()
  76                     .find(|item| item.ident.name == "paths")
  77                 {
  78                     if let ItemKind::Mod(ref paths_mod) = paths.node {
  79                         let mut last_name: Option<InternedString> = None;
  80                         for item in &paths_mod.items {
  81                             let name = item.ident.name.as_str();
  82                             if let Some(ref last_name) = last_name {
  83                                 if **last_name > *name {
  84                                     span_lint(
  85                                         cx,
  86                                         CLIPPY_LINTS_INTERNAL,
  87                                         item.span,
  88                                         "this constant should be before the previous constant due to lexical \
  89                                          ordering",
  90                                     );
  91                                 }
  92                             }
  93                             last_name = Some(name);
  94                         }
  95                     }
  96                 }
  97             }
  98         }
  99     }
 100 }
 101
 102
 103
 104 #[derive(Clone, Debug, Default)]
 105 pub struct LintWithoutLintPass {
 106     declared_lints: HashMap<Name, Span>,
 107     registered_lints: HashSet<Name>,
 108 }
 109
 110
 111 impl LintPass for LintWithoutLintPass {
 112     fn get_lints(&self) -> LintArray {
 113         lint_array!(LINT_WITHOUT_LINT_PASS)
 114     }
 115 }
 116
 117
 118 impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LintWithoutLintPass {
 119     fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
 120         if let ItemStatic(ref ty, MutImmutable, body_id) = item.node {
 121             if is_lint_ref_type(ty) {
 122                 self.declared_lints.insert(item.name, item.span);
 123             } else if is_lint_array_type(ty) && item.vis == Visibility::Inherited && item.name == "ARRAY" {
 124                 let mut collector = LintCollector {
 125                     output: &mut self.registered_lints,
 126                     cx: cx,
 127                 };
 128                 collector.visit_expr(&cx.tcx.hir.body(body_id).value);
 129             }
 130         }
 131     }
 132
 133     fn check_crate_post(&mut self, cx: &LateContext<'a, 'tcx>, _: &'tcx Crate) {
 134         for (lint_name, &lint_span) in &self.declared_lints {
 135             // When using the `declare_lint!` macro, the original `lint_span`'s
 136             // file points to "<rustc macros>".
 137             // `compiletest-rs` thinks that's an error in a different file and
 138             // just ignores it. This causes the test in compile-fail/lint_pass
 139             // not able to capture the error.
 140             // Therefore, we need to climb the macro expansion tree and find the
 141             // actual span that invoked `declare_lint!`:
 142             let lint_span = lint_span
 143                 .ctxt()
 144                 .outer()
 145                 .expn_info()
 146                 .map(|ei| ei.call_site)
 147                 .expect("unable to get call_site");
 148
 149             if !self.registered_lints.contains(lint_name) {
 150                 span_lint(
 151                     cx,
 152                     LINT_WITHOUT_LINT_PASS,
 153                     lint_span,
 154                     &format!("the lint `{}` is not added to any `LintPass`", lint_name),
 155                 );
 156             }
 157         }
 158     }
 159 }
 160
 161
 162 fn is_lint_ref_type(ty: &Ty) -> bool {
 163     if let TyRptr(
 164         _,
 165         MutTy {
 166             ty: ref inner,
 167             mutbl: MutImmutable,
 168         },
 169     ) = ty.node
 170     {
 171         if let TyPath(ref path) = inner.node {
 172             return match_qpath(path, &paths::LINT);
 173         }
 174     }
 175     false
 176 }
 177
 178
 179 fn is_lint_array_type(ty: &Ty) -> bool {
 180     if let TyPath(ref path) = ty.node {
 181         match_qpath(path, &paths::LINT_ARRAY)
 182     } else {
 183         false
 184     }
 185 }
 186
 187 struct LintCollector<'a, 'tcx: 'a> {
 188     output: &'a mut HashSet<Name>,
 189     cx: &'a LateContext<'a, 'tcx>,
 190 }
 191
 192 impl<'a, 'tcx: 'a> Visitor<'tcx> for LintCollector<'a, 'tcx> {
 193     fn visit_expr(&mut self, expr: &'tcx Expr) {
 194         walk_expr(self, expr);
 195     }
 196
 197     fn visit_path(&mut self, path: &'tcx Path, _: NodeId) {
 198         if path.segments.len() == 1 {
 199             self.output.insert(path.segments[0].name);
 200         }
 201     }
 202     fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
 203         NestedVisitorMap::All(&self.cx.tcx.hir)
 204     }
 205 }