84 lines
2.8 KiB
Rust
84 lines
2.8 KiB
Rust
use clippy_utils::consts::{constant, Constant};
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use clippy_utils::diagnostics::span_lint_and_help;
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use clippy_utils::is_inside_always_const_context;
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use clippy_utils::macros::{find_assert_args, root_macro_call_first_node, PanicExpn};
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use rustc_hir::{Expr, ExprKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_session::declare_lint_pass;
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use rustc_span::sym;
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declare_clippy_lint! {
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/// ### What it does
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/// Checks for `assert!(true)` and `assert!(false)` calls.
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///
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/// ### Why is this bad?
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/// Will be optimized out by the compiler or should probably be replaced by a
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/// `panic!()` or `unreachable!()`
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///
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/// ### Example
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/// ```rust,ignore
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/// assert!(false)
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/// assert!(true)
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/// const B: bool = false;
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/// assert!(B)
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/// ```
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#[clippy::version = "1.34.0"]
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pub ASSERTIONS_ON_CONSTANTS,
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style,
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"`assert!(true)` / `assert!(false)` will be optimized out by the compiler, and should probably be replaced by a `panic!()` or `unreachable!()`"
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}
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declare_lint_pass!(AssertionsOnConstants => [ASSERTIONS_ON_CONSTANTS]);
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impl<'tcx> LateLintPass<'tcx> for AssertionsOnConstants {
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fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
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let Some(macro_call) = root_macro_call_first_node(cx, e) else {
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return;
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};
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let is_debug = match cx.tcx.get_diagnostic_name(macro_call.def_id) {
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Some(sym::debug_assert_macro) => true,
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Some(sym::assert_macro) => false,
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_ => return,
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};
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let Some((condition, panic_expn)) = find_assert_args(cx, e, macro_call.expn) else {
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return;
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};
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let Some(Constant::Bool(val)) = constant(cx, cx.typeck_results(), condition) else {
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return;
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};
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match condition.kind {
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ExprKind::Path(..) | ExprKind::Lit(_) => {},
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_ if is_inside_always_const_context(cx.tcx, e.hir_id) => return,
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_ => {},
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}
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if val {
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span_lint_and_help(
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cx,
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ASSERTIONS_ON_CONSTANTS,
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macro_call.span,
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format!(
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"`{}!(true)` will be optimized out by the compiler",
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cx.tcx.item_name(macro_call.def_id)
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),
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None,
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"remove it",
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);
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} else if !is_debug {
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let (assert_arg, panic_arg) = match panic_expn {
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PanicExpn::Empty => ("", ""),
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_ => (", ..", ".."),
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};
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span_lint_and_help(
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cx,
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ASSERTIONS_ON_CONSTANTS,
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macro_call.span,
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format!("`assert!(false{assert_arg})` should probably be replaced"),
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None,
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format!("use `panic!({panic_arg})` or `unreachable!({panic_arg})`"),
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);
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}
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}
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}
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