From 9ff7c911008fc74c8d6c76afe12d7e30e67f8d25 Mon Sep 17 00:00:00 2001 From: Ariel Uy Date: Sun, 10 Jul 2022 14:37:38 -0700 Subject: [PATCH] Add new lint `obfuscated_if_else` New lint suggests using `if .. else ..` instead of `.then_some(..).unwrap_or(..)`. --- CHANGELOG.md | 1 + clippy_lints/src/lib.register_all.rs | 1 + clippy_lints/src/lib.register_lints.rs | 1 + clippy_lints/src/lib.register_style.rs | 1 + clippy_lints/src/methods/mod.rs | 34 +++++++++++++++ .../src/methods/obfuscated_if_else.rs | 42 +++++++++++++++++++ tests/ui/obfuscated_if_else.fixed | 7 ++++ tests/ui/obfuscated_if_else.rs | 7 ++++ tests/ui/obfuscated_if_else.stderr | 10 +++++ 9 files changed, 104 insertions(+) create mode 100644 clippy_lints/src/methods/obfuscated_if_else.rs create mode 100644 tests/ui/obfuscated_if_else.fixed create mode 100644 tests/ui/obfuscated_if_else.rs create mode 100644 tests/ui/obfuscated_if_else.stderr diff --git a/CHANGELOG.md b/CHANGELOG.md index 1b792736a6ae..00fce79ec063 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -3792,6 +3792,7 @@ Released 2018-09-13 [`nonsensical_open_options`]: https://rust-lang.github.io/rust-clippy/master/index.html#nonsensical_open_options [`nonstandard_macro_braces`]: https://rust-lang.github.io/rust-clippy/master/index.html#nonstandard_macro_braces [`not_unsafe_ptr_arg_deref`]: https://rust-lang.github.io/rust-clippy/master/index.html#not_unsafe_ptr_arg_deref +[`obfuscated_if_else`]: https://rust-lang.github.io/rust-clippy/master/index.html#obfuscated_if_else [`octal_escapes`]: https://rust-lang.github.io/rust-clippy/master/index.html#octal_escapes [`ok_expect`]: https://rust-lang.github.io/rust-clippy/master/index.html#ok_expect [`only_used_in_recursion`]: https://rust-lang.github.io/rust-clippy/master/index.html#only_used_in_recursion diff --git a/clippy_lints/src/lib.register_all.rs b/clippy_lints/src/lib.register_all.rs index da26a3f01301..69387d560c91 100644 --- a/clippy_lints/src/lib.register_all.rs +++ b/clippy_lints/src/lib.register_all.rs @@ -188,6 +188,7 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![ LintId::of(methods::NEEDLESS_SPLITN), LintId::of(methods::NEW_RET_NO_SELF), LintId::of(methods::NO_EFFECT_REPLACE), + LintId::of(methods::OBFUSCATED_IF_ELSE), LintId::of(methods::OK_EXPECT), LintId::of(methods::OPTION_AS_REF_DEREF), LintId::of(methods::OPTION_FILTER_MAP), diff --git a/clippy_lints/src/lib.register_lints.rs b/clippy_lints/src/lib.register_lints.rs index ceb8470657f7..24b921faf033 100644 --- a/clippy_lints/src/lib.register_lints.rs +++ b/clippy_lints/src/lib.register_lints.rs @@ -330,6 +330,7 @@ store.register_lints(&[ methods::NEEDLESS_SPLITN, methods::NEW_RET_NO_SELF, methods::NO_EFFECT_REPLACE, + methods::OBFUSCATED_IF_ELSE, methods::OK_EXPECT, methods::OPTION_AS_REF_DEREF, methods::OPTION_FILTER_MAP, diff --git a/clippy_lints/src/lib.register_style.rs b/clippy_lints/src/lib.register_style.rs index 15a1bc569af2..e95bab1d0454 100644 --- a/clippy_lints/src/lib.register_style.rs +++ b/clippy_lints/src/lib.register_style.rs @@ -70,6 +70,7 @@ store.register_group(true, "clippy::style", Some("clippy_style"), vec![ LintId::of(methods::MANUAL_SATURATING_ARITHMETIC), LintId::of(methods::MAP_COLLECT_RESULT_UNIT), LintId::of(methods::NEW_RET_NO_SELF), + LintId::of(methods::OBFUSCATED_IF_ELSE), LintId::of(methods::OK_EXPECT), LintId::of(methods::OPTION_MAP_OR_NONE), LintId::of(methods::RESULT_MAP_OR_INTO_OPTION), diff --git a/clippy_lints/src/methods/mod.rs b/clippy_lints/src/methods/mod.rs index 29ec6e042863..c252272e2540 100644 --- a/clippy_lints/src/methods/mod.rs +++ b/clippy_lints/src/methods/mod.rs @@ -46,6 +46,7 @@ mod map_unwrap_or; mod needless_option_as_deref; mod needless_option_take; mod no_effect_replace; +mod obfuscated_if_else; mod ok_expect; mod option_as_ref_deref; mod option_map_or_none; @@ -2259,6 +2260,35 @@ declare_clippy_lint! { "replace with no effect" } +declare_clippy_lint! { + /// ### What it does + /// Checks for usages of `.then_some(..).unwrap_or(..)` + /// + /// ### Why is this bad? + /// This can be written more clearly with `if .. else ..` + /// + /// ### Limitations + /// This lint currently only looks for usages of + /// `.then_some(..).unwrap_or(..)`, but will be expanded + /// to account for similar patterns. + /// + /// ### Example + /// ```rust + /// let x = true; + /// x.then_some("a").unwrap_or("b"); + /// ``` + /// Use instead: + /// ```rust + /// let x = true; + /// if x { "a" } else { "b" }; + /// ``` + #[clippy::version = "1.64.0"] + pub OBFUSCATED_IF_ELSE, + style, + "use of `.then_some(..).unwrap_or(..)` can be written \ + more clearly with `if .. else ..`" +} + pub struct Methods { avoid_breaking_exported_api: bool, msrv: Option, @@ -2360,6 +2390,7 @@ impl_lint_pass!(Methods => [ IS_DIGIT_ASCII_RADIX, NEEDLESS_OPTION_TAKE, NO_EFFECT_REPLACE, + OBFUSCATED_IF_ELSE, ]); /// Extracts a method call name, args, and `Span` of the method name. @@ -2768,6 +2799,9 @@ impl Methods { Some(("map", [m_recv, m_arg], span)) => { option_map_unwrap_or::check(cx, expr, m_recv, m_arg, recv, u_arg, span); }, + Some(("then_some", [t_recv, t_arg], _)) => { + obfuscated_if_else::check(cx, expr, t_recv, t_arg, u_arg); + }, _ => {}, }, ("unwrap_or_else", [u_arg]) => match method_call(recv) { diff --git a/clippy_lints/src/methods/obfuscated_if_else.rs b/clippy_lints/src/methods/obfuscated_if_else.rs new file mode 100644 index 000000000000..4d7427b26621 --- /dev/null +++ b/clippy_lints/src/methods/obfuscated_if_else.rs @@ -0,0 +1,42 @@ +// run-rustfix + +use super::OBFUSCATED_IF_ELSE; +use clippy_utils::{diagnostics::span_lint_and_sugg, source::snippet_with_applicability}; +use rustc_errors::Applicability; +use rustc_hir as hir; +use rustc_lint::LateContext; + +pub(super) fn check<'tcx>( + cx: &LateContext<'tcx>, + expr: &'tcx hir::Expr<'_>, + then_recv: &'tcx hir::Expr<'_>, + then_arg: &'tcx hir::Expr<'_>, + unwrap_arg: &'tcx hir::Expr<'_>, +) { + // something.then_some(blah).unwrap_or(blah) + // ^^^^^^^^^-then_recv ^^^^-then_arg ^^^^- unwrap_arg + // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^- expr + + let recv_ty = cx.typeck_results().expr_ty(then_recv); + + if recv_ty.is_bool() { + let mut applicability = Applicability::MachineApplicable; + let sugg = format!( + "if {} {{ {} }} else {{ {} }}", + snippet_with_applicability(cx, then_recv.span, "..", &mut applicability), + snippet_with_applicability(cx, then_arg.span, "..", &mut applicability), + snippet_with_applicability(cx, unwrap_arg.span, "..", &mut applicability) + ); + + span_lint_and_sugg( + cx, + OBFUSCATED_IF_ELSE, + expr.span, + "use of `.then_some(..).unwrap_or(..)` can be written \ + more clearly with `if .. else ..`", + "try", + sugg, + applicability, + ); + } +} diff --git a/tests/ui/obfuscated_if_else.fixed b/tests/ui/obfuscated_if_else.fixed new file mode 100644 index 000000000000..62d932c2c6b7 --- /dev/null +++ b/tests/ui/obfuscated_if_else.fixed @@ -0,0 +1,7 @@ +// run-rustfix + +#![warn(clippy::obfuscated_if_else)] + +fn main() { + if true { "a" } else { "b" }; +} diff --git a/tests/ui/obfuscated_if_else.rs b/tests/ui/obfuscated_if_else.rs new file mode 100644 index 000000000000..273be9092a74 --- /dev/null +++ b/tests/ui/obfuscated_if_else.rs @@ -0,0 +1,7 @@ +// run-rustfix + +#![warn(clippy::obfuscated_if_else)] + +fn main() { + true.then_some("a").unwrap_or("b"); +} diff --git a/tests/ui/obfuscated_if_else.stderr b/tests/ui/obfuscated_if_else.stderr new file mode 100644 index 000000000000..e4180c288693 --- /dev/null +++ b/tests/ui/obfuscated_if_else.stderr @@ -0,0 +1,10 @@ +error: use of `.then_some(..).unwrap_or(..)` can be written more clearly with `if .. else ..` + --> $DIR/obfuscated_if_else.rs:6:5 + | +LL | true.then_some("a").unwrap_or("b"); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `if true { "a" } else { "b" }` + | + = note: `-D clippy::obfuscated-if-else` implied by `-D warnings` + +error: aborting due to previous error +