diff options
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/question_mark_used.rs')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/question_mark_used.rs | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/question_mark_used.rs b/src/tools/clippy/clippy_lints/src/question_mark_used.rs new file mode 100644 index 000000000..9b678e8d7 --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/question_mark_used.rs @@ -0,0 +1,52 @@ +use clippy_utils::diagnostics::span_lint_and_help; + +use clippy_utils::macros::span_is_local; +use rustc_hir::{Expr, ExprKind, MatchSource}; +use rustc_lint::{LateContext, LateLintPass}; +use rustc_session::{declare_lint_pass, declare_tool_lint}; + +declare_clippy_lint! { + /// ### What it does + /// Checks for expressions that use the question mark operator and rejects them. + /// + /// ### Why is this bad? + /// Sometimes code wants to avoid the question mark operator because for instance a local + /// block requires a macro to re-throw errors to attach additional information to the + /// error. + /// + /// ### Example + /// ```ignore + /// let result = expr?; + /// ``` + /// + /// Could be written: + /// + /// ```ignore + /// utility_macro!(expr); + /// ``` + #[clippy::version = "pre 1.29.0"] + pub QUESTION_MARK_USED, + restriction, + "complains if the question mark operator is used" +} + +declare_lint_pass!(QuestionMarkUsed => [QUESTION_MARK_USED]); + +impl<'tcx> LateLintPass<'tcx> for QuestionMarkUsed { + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + if let ExprKind::Match(_, _, MatchSource::TryDesugar) = expr.kind { + if !span_is_local(expr.span) { + return; + } + + span_lint_and_help( + cx, + QUESTION_MARK_USED, + expr.span, + "question mark operator was used", + None, + "consider using a custom macro or match expression", + ); + } + } +} |