src/tools/clippy/clippy_lints/src/dbg_macro.rs

   1 use crate::utils::{snippet_opt, span_lint_and_help, span_lint_and_sugg};
   2 use rustc_ast::ast;
   3 use rustc_ast::tokenstream::TokenStream;
   4 use rustc_errors::Applicability;
   5 use rustc_lint::{EarlyContext, EarlyLintPass};
   6 use rustc_session::{declare_lint_pass, declare_tool_lint};
   7 use rustc_span::source_map::Span;
   8
   9 declare_clippy_lint! {
  10     /// **What it does:** Checks for usage of dbg!() macro.
  11     ///
  12     /// **Why is this bad?** `dbg!` macro is intended as a debugging tool. It
  13     /// should not be in version control.
  14     ///
  15     /// **Known problems:** None.
  16     ///
  17     /// **Example:**
  18     /// ```rust,ignore
  19     /// // Bad
  20     /// dbg!(true)
  21     ///
  22     /// // Good
  23     /// true
  24     /// ```
  25     pub DBG_MACRO,
  26     restriction,
  27     "`dbg!` macro is intended as a debugging tool"
  28 }
  29
  30 declare_lint_pass!(DbgMacro => [DBG_MACRO]);
  31
  32 impl EarlyLintPass for DbgMacro {
  33     fn check_mac(&mut self, cx: &EarlyContext<'_>, mac: &ast::MacCall) {
  34         if mac.path == sym!(dbg) {
  35             if let Some(sugg) = tts_span(mac.args.inner_tokens()).and_then(|span| snippet_opt(cx, span)) {
  36                 span_lint_and_sugg(
  37                     cx,
  38                     DBG_MACRO,
  39                     mac.span(),
  40                     "`dbg!` macro is intended as a debugging tool",
  41                     "ensure to avoid having uses of it in version control",
  42                     sugg,
  43                     Applicability::MaybeIncorrect,
  44                 );
  45             } else {
  46                 span_lint_and_help(
  47                     cx,
  48                     DBG_MACRO,
  49                     mac.span(),
  50                     "`dbg!` macro is intended as a debugging tool",
  51                     None,
  52                     "ensure to avoid having uses of it in version control",
  53                 );
  54             }
  55         }
  56     }
  57 }
  58
  59 // Get span enclosing entire the token stream.
  60 fn tts_span(tts: TokenStream) -> Option<Span> {
  61     let mut cursor = tts.into_trees();
  62     let first = cursor.next()?.span();
  63     let span = cursor.last().map_or(first, |tree| first.to(tree.span()));
  64     Some(span)
  65 }