85 lines
2.8 KiB
Rust
85 lines
2.8 KiB
Rust
use crate::utils::{find_macro_calls, 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::FnKind;
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::{declare_lint_pass, declare_tool_lint};
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use rustc_span::{sym, Span};
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declare_clippy_lint! {
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/// **What it does:** Checks for usage of `panic!`, `unimplemented!`, `todo!`, `unreachable!` or assertions 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 panicking macros should be avoided.
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///
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/// **Known problems:** Functions called from a function returning a `Result` may invoke a panicking macro. This is not checked.
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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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/// Use instead:
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/// ```rust
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/// fn result_without_panic() -> Result<bool, String> {
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/// Err(String::from("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!()`, `unreachable()`, `unimplemented()` or assertion"
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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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fn lint_impl_body<'tcx>(cx: &LateContext<'tcx>, impl_span: Span, body: &'tcx hir::Body<'tcx>) {
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let panics = find_macro_calls(
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&[
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"unimplemented",
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"unreachable",
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"panic",
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"todo",
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"assert",
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"assert_eq",
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"assert_ne",
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"debug_assert",
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"debug_assert_eq",
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"debug_assert_ne",
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],
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body,
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);
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if !panics.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!()`, `panic!()` or assertion 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!()`, `panic!()` or assertions 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, "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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