91 lines
3.0 KiB
Rust
91 lines
3.0 KiB
Rust
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use crate::utils::{is_expn_of, is_type_diagnostic_item, return_ty, span_lint_and_then};
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use rustc_hir as hir;
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use rustc_hir::intravisit::{self, FnKind, NestedVisitorMap, Visitor};
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use rustc_hir::Expr;
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::hir::map::Map;
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::Span;
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `panic!`, `unimplemented!`, `todo!` or `unreachable!` in a function of type result.
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///
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/// **Why is this bad?** For some codebases, it is desirable for functions of type result to return an error instead of crashing. Hence unimplemented, panic and unreachable should be avoided.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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///
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/// ```rust
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/// fn result_with_panic() -> Result<bool, String>
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/// {
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/// panic!("error");
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/// }
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/// ```
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pub PANIC_IN_RESULT_FN,
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restriction,
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"functions of type `Result<..>` that contain `panic!()`, `todo!()` or `unreachable()` or `unimplemented()` "
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}
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declare_lint_pass!(PanicInResultFn => [PANIC_IN_RESULT_FN]);
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impl<'tcx> LateLintPass<'tcx> for PanicInResultFn {
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fn check_fn(
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&mut self,
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cx: &LateContext<'tcx>,
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fn_kind: FnKind<'tcx>,
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_: &'tcx hir::FnDecl<'tcx>,
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body: &'tcx hir::Body<'tcx>,
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span: Span,
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hir_id: hir::HirId,
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) {
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if !matches!(fn_kind, FnKind::Closure(_))
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&& is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym!(result_type))
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{
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lint_impl_body(cx, span, body);
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}
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}
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}
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struct FindPanicUnimplementedUnreachable {
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result: Vec<Span>,
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}
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impl<'tcx> Visitor<'tcx> for FindPanicUnimplementedUnreachable {
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type Map = Map<'tcx>;
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fn visit_expr(&mut self, expr: &'tcx Expr<'_>) {
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if ["unimplemented", "unreachable", "panic", "todo"]
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.iter()
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.any(|fun| is_expn_of(expr.span, fun).is_some())
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{
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self.result.push(expr.span);
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}
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// and check sub-expressions
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intravisit::walk_expr(self, expr);
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}
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fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
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NestedVisitorMap::None
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}
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}
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fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir::Body<'tcx>) {
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let mut panics = FindPanicUnimplementedUnreachable { result: Vec::new() };
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panics.visit_expr(&body.value);
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if !panics.result.is_empty() {
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span_lint_and_then(
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cx,
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PANIC_IN_RESULT_FN,
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impl_span,
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"used `unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` in a function that returns `Result`",
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move |diag| {
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diag.help(
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"`unimplemented!()`, `unreachable!()`, `todo!()` or `panic!()` should not be used in a function that returns `Result` as `Result` is expected to return an error instead of crashing",
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);
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diag.span_note(panics.result, "return Err() instead of panicking");
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},
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);
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}
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}
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