70 lines
2.5 KiB
Rust
70 lines
2.5 KiB
Rust
use rustc::hir::{Expr, ExprKind};
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use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
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use rustc::{declare_lint_pass, declare_tool_lint};
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use crate::consts::{constant, Constant};
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use crate::utils::{in_macro_or_desugar, is_direct_expn_of, is_expn_of, span_help_and_lint};
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declare_clippy_lint! {
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/// **What it does:** Checks for `assert!(true)` and `assert!(false)` calls.
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///
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/// **Why is this bad?** 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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/// **Known problems:** None
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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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/// // or
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/// assert!(true)
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/// // or
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/// const B: bool = false;
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/// assert!(B)
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/// ```
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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<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
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fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, e: &'tcx Expr) {
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let lint_assert_cb = |is_debug_assert: bool| {
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if let ExprKind::Unary(_, ref lit) = e.node {
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if let Some((Constant::Bool(is_true), _)) = constant(cx, cx.tables, lit) {
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if is_true {
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span_help_and_lint(
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cx,
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ASSERTIONS_ON_CONSTANTS,
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e.span,
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"`assert!(true)` will be optimized out by the compiler",
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"remove it",
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);
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} else if !is_debug_assert {
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span_help_and_lint(
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cx,
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ASSERTIONS_ON_CONSTANTS,
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e.span,
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"`assert!(false)` should probably be replaced",
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"use `panic!()` or `unreachable!()`",
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);
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}
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}
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}
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};
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if let Some(debug_assert_span) = is_expn_of(e.span, "debug_assert") {
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if in_macro_or_desugar(debug_assert_span) {
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return;
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}
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lint_assert_cb(true);
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} else if let Some(assert_span) = is_direct_expn_of(e.span, "assert") {
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if in_macro_or_desugar(assert_span) {
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return;
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}
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lint_assert_cb(false);
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}
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}
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}
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