mirror of
https://github.com/rust-lang/rust-clippy
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786f874c34
changelog: none Sorry, this is a big one. A lot of interrelated changes and I wanted to put the new utils to use to make sure they are somewhat battle-tested. We may want to divide some of the lint-specific refactoring commits into batches for smaller reviewing tasks. I could also split into more PRs. Introduces a bunch of new utils at `clippy_utils::macros::...`. Please read through the docs and give any feedback! I'm happy to introduce `MacroCall` and various functions to retrieve an instance. It feels like the missing puzzle piece. I'm also introducing `ExpnId` from rustc as "useful for Clippy too". `@rust-lang/clippy` Fixes #7843 by not parsing every node of macro implementations, at least the major offenders. I probably want to get rid of `is_expn_of` at some point.
87 lines
3.1 KiB
Rust
87 lines
3.1 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_then;
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use clippy_utils::macros::root_macro_call_first_node;
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use clippy_utils::return_ty;
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use clippy_utils::ty::is_type_diagnostic_item;
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use clippy_utils::visitors::expr_visitor_no_bodies;
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use rustc_hir as hir;
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use rustc_hir::intravisit::{FnKind, Visitor};
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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
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/// 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?
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/// 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
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/// 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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/// ```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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#[clippy::version = "1.48.0"]
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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) && is_type_diagnostic_item(cx, return_ty(cx, hir_id), sym::Result) {
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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 mut panics = Vec::new();
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expr_visitor_no_bodies(|expr| {
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let Some(macro_call) = root_macro_call_first_node(cx, expr) else { return true };
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if matches!(
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&*cx.tcx.item_name(macro_call.def_id).as_str(),
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"unimplemented" | "unreachable" | "panic" | "todo" | "assert" | "assert_eq" | "assert_ne"
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) {
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panics.push(macro_call.span);
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return false;
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}
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true
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})
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.visit_expr(&body.value);
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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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