diff options
| -rw-r--r-- | CHANGELOG.md | 1 | ||||
| -rw-r--r-- | clippy_lints/src/declared_lints.rs | 1 | ||||
| -rw-r--r-- | clippy_lints/src/loops/mod.rs | 36 | ||||
| -rw-r--r-- | clippy_lints/src/loops/while_float.rs | 20 | ||||
| -rw-r--r-- | tests/ui/while_float.rs | 14 | ||||
| -rw-r--r-- | tests/ui/while_float.stderr | 20 |
6 files changed, 92 insertions, 0 deletions
diff --git a/CHANGELOG.md b/CHANGELOG.md index e17d6b3cf27..d5115f70f66 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -5911,6 +5911,7 @@ Released 2018-09-13 [`verbose_file_reads`]: https://rust-lang.github.io/rust-clippy/master/index.html#verbose_file_reads [`vtable_address_comparisons`]: https://rust-lang.github.io/rust-clippy/master/index.html#vtable_address_comparisons [`waker_clone_wake`]: https://rust-lang.github.io/rust-clippy/master/index.html#waker_clone_wake +[`while_float`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_float [`while_immutable_condition`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_immutable_condition [`while_let_loop`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_let_loop [`while_let_on_iterator`]: https://rust-lang.github.io/rust-clippy/master/index.html#while_let_on_iterator diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs index 6850ec821e8..df2ef465700 100644 --- a/clippy_lints/src/declared_lints.rs +++ b/clippy_lints/src/declared_lints.rs @@ -293,6 +293,7 @@ pub(crate) static LINTS: &[&crate::LintInfo] = &[ crate::loops::SAME_ITEM_PUSH_INFO, crate::loops::SINGLE_ELEMENT_LOOP_INFO, crate::loops::UNUSED_ENUMERATE_INDEX_INFO, + crate::loops::WHILE_FLOAT_INFO, crate::loops::WHILE_IMMUTABLE_CONDITION_INFO, crate::loops::WHILE_LET_LOOP_INFO, crate::loops::WHILE_LET_ON_ITERATOR_INFO, diff --git a/clippy_lints/src/loops/mod.rs b/clippy_lints/src/loops/mod.rs index b5e39b33c6a..3dcb050d77e 100644 --- a/clippy_lints/src/loops/mod.rs +++ b/clippy_lints/src/loops/mod.rs @@ -17,6 +17,7 @@ mod same_item_push; mod single_element_loop; mod unused_enumerate_index; mod utils; +mod while_float; mod while_immutable_condition; mod while_let_loop; mod while_let_on_iterator; @@ -418,6 +419,39 @@ declare_clippy_lint! { declare_clippy_lint! { /// ### What it does + /// Checks for while loops comparing floating point values. + /// + /// ### Why is this bad? + /// If you increment floating point values, errors can compound, + /// so, use integers instead if possible. + /// + /// ### Known problems + /// The lint will catch all while loops comparing floating point + /// values without regarding the increment. + /// + /// ### Example + /// ```no_run + /// let mut x = 0.0; + /// while x < 42.0 { + /// x += 1.0; + /// } + /// ``` + /// + /// Use instead: + /// ```no_run + /// let mut x = 0; + /// while x < 42 { + /// x += 1; + /// } + /// ``` + #[clippy::version = "1.80.0"] + pub WHILE_FLOAT, + nursery, + "while loops comaparing floating point values" +} + +declare_clippy_lint! { + /// ### What it does /// Checks whether a for loop is being used to push a constant /// value into a Vec. /// @@ -706,6 +740,7 @@ impl_lint_pass!(Loops => [ NEVER_LOOP, MUT_RANGE_BOUND, WHILE_IMMUTABLE_CONDITION, + WHILE_FLOAT, SAME_ITEM_PUSH, SINGLE_ELEMENT_LOOP, MISSING_SPIN_LOOP, @@ -762,6 +797,7 @@ impl<'tcx> LateLintPass<'tcx> for Loops { if let Some(higher::While { condition, body, span }) = higher::While::hir(expr) { while_immutable_condition::check(cx, condition, body); + while_float::check(cx, condition); missing_spin_loop::check(cx, condition, body); manual_while_let_some::check(cx, condition, body, span); } diff --git a/clippy_lints/src/loops/while_float.rs b/clippy_lints/src/loops/while_float.rs new file mode 100644 index 00000000000..cf62ce29f0c --- /dev/null +++ b/clippy_lints/src/loops/while_float.rs @@ -0,0 +1,20 @@ +use clippy_utils::diagnostics::span_lint; +use rustc_hir::ExprKind; + +pub(super) fn check(cx: &rustc_lint::LateContext<'_>, condition: &rustc_hir::Expr<'_>) { + if let ExprKind::Binary(_op, left, right) = condition.kind + && is_float_type(cx, left) + && is_float_type(cx, right) + { + span_lint( + cx, + super::WHILE_FLOAT, + condition.span, + "while condition comparing floats", + ); + } +} + +fn is_float_type(cx: &rustc_lint::LateContext<'_>, expr: &rustc_hir::Expr<'_>) -> bool { + cx.typeck_results().expr_ty(expr).is_floating_point() +} diff --git a/tests/ui/while_float.rs b/tests/ui/while_float.rs new file mode 100644 index 00000000000..a3b0618948e --- /dev/null +++ b/tests/ui/while_float.rs @@ -0,0 +1,14 @@ +#[deny(clippy::while_float)] +fn main() { + let mut x = 0.0_f32; + while x < 42.0_f32 { + x += 0.5; + } + while x < 42.0 { + x += 1.0; + } + let mut x = 0; + while x < 42 { + x += 1; + } +} diff --git a/tests/ui/while_float.stderr b/tests/ui/while_float.stderr new file mode 100644 index 00000000000..b8e934b97c6 --- /dev/null +++ b/tests/ui/while_float.stderr @@ -0,0 +1,20 @@ +error: while condition comparing floats + --> tests/ui/while_float.rs:4:11 + | +LL | while x < 42.0_f32 { + | ^^^^^^^^^^^^ + | +note: the lint level is defined here + --> tests/ui/while_float.rs:1:8 + | +LL | #[deny(clippy::while_float)] + | ^^^^^^^^^^^^^^^^^^^ + +error: while condition comparing floats + --> tests/ui/while_float.rs:7:11 + | +LL | while x < 42.0 { + | ^^^^^^^^ + +error: aborting due to 2 previous errors + |