diff --git a/clippy_lints/src/redundant_pattern_matching.rs b/clippy_lints/src/redundant_pattern_matching.rs index 7ee298e9833..b95b12c4eb5 100644 --- a/clippy_lints/src/redundant_pattern_matching.rs +++ b/clippy_lints/src/redundant_pattern_matching.rs @@ -1,10 +1,13 @@ -use crate::utils::{match_qpath, match_trait_method, paths, snippet, span_lint_and_then}; +use crate::utils::{in_constant, match_qpath, match_trait_method, paths, snippet, span_lint_and_then}; use if_chain::if_chain; use rustc_ast::ast::LitKind; use rustc_errors::Applicability; -use rustc_hir::{Arm, Expr, ExprKind, MatchSource, PatKind, QPath}; +use rustc_hir::{Arm, Expr, ExprKind, HirId, MatchSource, PatKind, QPath}; use rustc_lint::{LateContext, LateLintPass}; +use rustc_middle::ty; +use rustc_mir::const_eval::is_const_fn; use rustc_session::{declare_lint_pass, declare_tool_lint}; +use rustc_span::source_map::Symbol; declare_clippy_lint! { /// **What it does:** Lint for redundant pattern matching over `Result` or @@ -64,26 +67,37 @@ fn find_sugg_for_if_let<'a, 'tcx>( arms: &[Arm<'_>], keyword: &'static str, ) { + fn find_suggestion(cx: &LateContext<'_, '_>, hir_id: HirId, path: &QPath<'_>) -> Option<&'static str> { + if match_qpath(path, &paths::RESULT_OK) && can_suggest(cx, hir_id, sym!(result_type), "is_ok") { + return Some("is_ok()"); + } + if match_qpath(path, &paths::RESULT_ERR) && can_suggest(cx, hir_id, sym!(result_type), "is_err") { + return Some("is_err()"); + } + if match_qpath(path, &paths::OPTION_SOME) && can_suggest(cx, hir_id, sym!(option_type), "is_some") { + return Some("is_some()"); + } + if match_qpath(path, &paths::OPTION_NONE) && can_suggest(cx, hir_id, sym!(option_type), "is_none") { + return Some("is_none()"); + } + None + } + + let hir_id = expr.hir_id; let good_method = match arms[0].pat.kind { PatKind::TupleStruct(ref path, ref patterns, _) if patterns.len() == 1 => { if let PatKind::Wild = patterns[0].kind { - if match_qpath(path, &paths::RESULT_OK) { - "is_ok()" - } else if match_qpath(path, &paths::RESULT_ERR) { - "is_err()" - } else if match_qpath(path, &paths::OPTION_SOME) { - "is_some()" - } else { - return; - } + find_suggestion(cx, hir_id, path) } else { - return; + None } }, - - PatKind::Path(ref path) if match_qpath(path, &paths::OPTION_NONE) => "is_none()", - - _ => return, + PatKind::Path(ref path) => find_suggestion(cx, hir_id, path), + _ => None, + }; + let good_method = match good_method { + Some(method) => method, + None => return, }; // check that `while_let_on_iterator` lint does not trigger @@ -128,6 +142,7 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_ if arms.len() == 2 { let node_pair = (&arms[0].pat.kind, &arms[1].pat.kind); + let hir_id = expr.hir_id; let found_good_method = match node_pair { ( PatKind::TupleStruct(ref path_left, ref patterns_left, _), @@ -142,6 +157,8 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_ &paths::RESULT_ERR, "is_ok()", "is_err()", + || can_suggest(cx, hir_id, sym!(result_type), "is_ok"), + || can_suggest(cx, hir_id, sym!(result_type), "is_err"), ) } else { None @@ -160,6 +177,8 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_ &paths::OPTION_NONE, "is_some()", "is_none()", + || can_suggest(cx, hir_id, sym!(option_type), "is_some"), + || can_suggest(cx, hir_id, sym!(option_type), "is_none"), ) } else { None @@ -188,6 +207,7 @@ fn find_sugg_for_match<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr<'_ } } +#[allow(clippy::too_many_arguments)] fn find_good_method_for_match<'a>( arms: &[Arm<'_>], path_left: &QPath<'_>, @@ -196,6 +216,8 @@ fn find_good_method_for_match<'a>( expected_right: &[&str], should_be_left: &'a str, should_be_right: &'a str, + can_suggest_left: impl Fn() -> bool, + can_suggest_right: impl Fn() -> bool, ) -> Option<&'a str> { let body_node_pair = if match_qpath(path_left, expected_left) && match_qpath(path_right, expected_right) { (&(*arms[0].body).kind, &(*arms[1].body).kind) @@ -207,10 +229,32 @@ fn find_good_method_for_match<'a>( match body_node_pair { (ExprKind::Lit(ref lit_left), ExprKind::Lit(ref lit_right)) => match (&lit_left.node, &lit_right.node) { - (LitKind::Bool(true), LitKind::Bool(false)) => Some(should_be_left), - (LitKind::Bool(false), LitKind::Bool(true)) => Some(should_be_right), + (LitKind::Bool(true), LitKind::Bool(false)) if can_suggest_left() => Some(should_be_left), + (LitKind::Bool(false), LitKind::Bool(true)) if can_suggest_right() => Some(should_be_right), _ => None, }, _ => None, } } + +fn can_suggest(cx: &LateContext<'_, '_>, hir_id: HirId, diag_item: Symbol, name: &str) -> bool { + if !in_constant(cx, hir_id) { + return true; + } + + // Avoid suggesting calls to non-`const fn`s in const contexts, see #5697. + cx.tcx + .get_diagnostic_item(diag_item) + .and_then(|def_id| { + cx.tcx.inherent_impls(def_id).iter().find_map(|imp| { + cx.tcx + .associated_items(*imp) + .in_definition_order() + .find_map(|item| match item.kind { + ty::AssocKind::Fn if item.ident.name.as_str() == name => Some(item.def_id), + _ => None, + }) + }) + }) + .map_or(false, |def_id| is_const_fn(cx.tcx, def_id)) +} diff --git a/tests/ui/redundant_pattern_matching.fixed b/tests/ui/redundant_pattern_matching.fixed index fc8cb0e747c..6ba5cfb1d71 100644 --- a/tests/ui/redundant_pattern_matching.fixed +++ b/tests/ui/redundant_pattern_matching.fixed @@ -1,5 +1,7 @@ // run-rustfix +#![feature(const_if_match)] +#![feature(const_loop)] #![warn(clippy::all)] #![warn(clippy::redundant_pattern_matching)] #![allow(clippy::unit_arg, unused_must_use, clippy::needless_bool, deprecated)] @@ -67,6 +69,7 @@ fn main() { takes_bool(x); issue5504(); + issue5697(); let _ = if gen_opt().is_some() { 1 @@ -117,3 +120,42 @@ fn issue5504() { if m!().is_some() {} while m!().is_some() {} } + +// None of these should be linted because none of the suggested methods +// are `const fn` without toggling a feature. +const fn issue5697() { + if let Ok(_) = Ok::(42) {} + + if let Err(_) = Err::(42) {} + + if let Some(_) = Some(42) {} + + if let None = None::<()> {} + + while let Ok(_) = Ok::(10) {} + + while let Err(_) = Ok::(10) {} + + while let Some(_) = Some(42) {} + + while let None = None::<()> {} + + match Ok::(42) { + Ok(_) => true, + Err(_) => false, + }; + + match Err::(42) { + Ok(_) => false, + Err(_) => true, + }; + match Some(42) { + Some(_) => true, + None => false, + }; + + match None::<()> { + Some(_) => false, + None => true, + }; +} diff --git a/tests/ui/redundant_pattern_matching.rs b/tests/ui/redundant_pattern_matching.rs index 51912dade03..17de66f9ad0 100644 --- a/tests/ui/redundant_pattern_matching.rs +++ b/tests/ui/redundant_pattern_matching.rs @@ -1,5 +1,7 @@ // run-rustfix +#![feature(const_if_match)] +#![feature(const_loop)] #![warn(clippy::all)] #![warn(clippy::redundant_pattern_matching)] #![allow(clippy::unit_arg, unused_must_use, clippy::needless_bool, deprecated)] @@ -88,6 +90,7 @@ fn main() { takes_bool(x); issue5504(); + issue5697(); let _ = if let Some(_) = gen_opt() { 1 @@ -138,3 +141,42 @@ fn issue5504() { if let Some(_) = m!() {} while let Some(_) = m!() {} } + +// None of these should be linted because none of the suggested methods +// are `const fn` without toggling a feature. +const fn issue5697() { + if let Ok(_) = Ok::(42) {} + + if let Err(_) = Err::(42) {} + + if let Some(_) = Some(42) {} + + if let None = None::<()> {} + + while let Ok(_) = Ok::(10) {} + + while let Err(_) = Ok::(10) {} + + while let Some(_) = Some(42) {} + + while let None = None::<()> {} + + match Ok::(42) { + Ok(_) => true, + Err(_) => false, + }; + + match Err::(42) { + Ok(_) => false, + Err(_) => true, + }; + match Some(42) { + Some(_) => true, + None => false, + }; + + match None::<()> { + Some(_) => false, + None => true, + }; +} diff --git a/tests/ui/redundant_pattern_matching.stderr b/tests/ui/redundant_pattern_matching.stderr index b58deb7954e..1b9a4b40a2f 100644 --- a/tests/ui/redundant_pattern_matching.stderr +++ b/tests/ui/redundant_pattern_matching.stderr @@ -1,5 +1,5 @@ error: redundant pattern matching, consider using `is_ok()` - --> $DIR/redundant_pattern_matching.rs:8:12 + --> $DIR/redundant_pattern_matching.rs:10:12 | LL | if let Ok(_) = Ok::(42) {} | -------^^^^^--------------------- help: try this: `if Ok::(42).is_ok()` @@ -7,67 +7,67 @@ LL | if let Ok(_) = Ok::(42) {} = note: `-D clippy::redundant-pattern-matching` implied by `-D warnings` error: redundant pattern matching, consider using `is_err()` - --> $DIR/redundant_pattern_matching.rs:10:12 + --> $DIR/redundant_pattern_matching.rs:12:12 | LL | if let Err(_) = Err::(42) {} | -------^^^^^^---------------------- help: try this: `if Err::(42).is_err()` error: redundant pattern matching, consider using `is_none()` - --> $DIR/redundant_pattern_matching.rs:12:12 + --> $DIR/redundant_pattern_matching.rs:14:12 | LL | if let None = None::<()> {} | -------^^^^------------- help: try this: `if None::<()>.is_none()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:14:12 + --> $DIR/redundant_pattern_matching.rs:16:12 | LL | if let Some(_) = Some(42) {} | -------^^^^^^^----------- help: try this: `if Some(42).is_some()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:16:12 + --> $DIR/redundant_pattern_matching.rs:18:12 | LL | if let Some(_) = Some(42) { | -------^^^^^^^----------- help: try this: `if Some(42).is_some()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:22:15 + --> $DIR/redundant_pattern_matching.rs:24:15 | LL | while let Some(_) = Some(42) {} | ----------^^^^^^^----------- help: try this: `while Some(42).is_some()` error: redundant pattern matching, consider using `is_none()` - --> $DIR/redundant_pattern_matching.rs:24:15 + --> $DIR/redundant_pattern_matching.rs:26:15 | LL | while let None = Some(42) {} | ----------^^^^----------- help: try this: `while Some(42).is_none()` error: redundant pattern matching, consider using `is_none()` - --> $DIR/redundant_pattern_matching.rs:26:15 + --> $DIR/redundant_pattern_matching.rs:28:15 | LL | while let None = None::<()> {} | ----------^^^^------------- help: try this: `while None::<()>.is_none()` error: redundant pattern matching, consider using `is_ok()` - --> $DIR/redundant_pattern_matching.rs:28:15 + --> $DIR/redundant_pattern_matching.rs:30:15 | LL | while let Ok(_) = Ok::(10) {} | ----------^^^^^--------------------- help: try this: `while Ok::(10).is_ok()` error: redundant pattern matching, consider using `is_err()` - --> $DIR/redundant_pattern_matching.rs:30:15 + --> $DIR/redundant_pattern_matching.rs:32:15 | LL | while let Err(_) = Ok::(10) {} | ----------^^^^^^--------------------- help: try this: `while Ok::(10).is_err()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:33:15 + --> $DIR/redundant_pattern_matching.rs:35:15 | LL | while let Some(_) = v.pop() { | ----------^^^^^^^---------- help: try this: `while v.pop().is_some()` error: redundant pattern matching, consider using `is_ok()` - --> $DIR/redundant_pattern_matching.rs:49:5 + --> $DIR/redundant_pattern_matching.rs:51:5 | LL | / match Ok::(42) { LL | | Ok(_) => true, @@ -76,7 +76,7 @@ LL | | }; | |_____^ help: try this: `Ok::(42).is_ok()` error: redundant pattern matching, consider using `is_err()` - --> $DIR/redundant_pattern_matching.rs:54:5 + --> $DIR/redundant_pattern_matching.rs:56:5 | LL | / match Ok::(42) { LL | | Ok(_) => false, @@ -85,7 +85,7 @@ LL | | }; | |_____^ help: try this: `Ok::(42).is_err()` error: redundant pattern matching, consider using `is_err()` - --> $DIR/redundant_pattern_matching.rs:59:5 + --> $DIR/redundant_pattern_matching.rs:61:5 | LL | / match Err::(42) { LL | | Ok(_) => false, @@ -94,7 +94,7 @@ LL | | }; | |_____^ help: try this: `Err::(42).is_err()` error: redundant pattern matching, consider using `is_ok()` - --> $DIR/redundant_pattern_matching.rs:64:5 + --> $DIR/redundant_pattern_matching.rs:66:5 | LL | / match Err::(42) { LL | | Ok(_) => true, @@ -103,7 +103,7 @@ LL | | }; | |_____^ help: try this: `Err::(42).is_ok()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:69:5 + --> $DIR/redundant_pattern_matching.rs:71:5 | LL | / match Some(42) { LL | | Some(_) => true, @@ -112,7 +112,7 @@ LL | | }; | |_____^ help: try this: `Some(42).is_some()` error: redundant pattern matching, consider using `is_none()` - --> $DIR/redundant_pattern_matching.rs:74:5 + --> $DIR/redundant_pattern_matching.rs:76:5 | LL | / match None::<()> { LL | | Some(_) => false, @@ -121,7 +121,7 @@ LL | | }; | |_____^ help: try this: `None::<()>.is_none()` error: redundant pattern matching, consider using `is_none()` - --> $DIR/redundant_pattern_matching.rs:79:13 + --> $DIR/redundant_pattern_matching.rs:81:13 | LL | let _ = match None::<()> { | _____________^ @@ -131,61 +131,61 @@ LL | | }; | |_____^ help: try this: `None::<()>.is_none()` error: redundant pattern matching, consider using `is_ok()` - --> $DIR/redundant_pattern_matching.rs:84:20 + --> $DIR/redundant_pattern_matching.rs:86:20 | LL | let _ = if let Ok(_) = Ok::(4) { true } else { false }; | -------^^^^^--------------------- help: try this: `if Ok::(4).is_ok()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:87:20 + --> $DIR/redundant_pattern_matching.rs:89:20 | LL | let x = if let Some(_) = opt { true } else { false }; | -------^^^^^^^------ help: try this: `if opt.is_some()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:92:20 + --> $DIR/redundant_pattern_matching.rs:95:20 | LL | let _ = if let Some(_) = gen_opt() { | -------^^^^^^^------------ help: try this: `if gen_opt().is_some()` error: redundant pattern matching, consider using `is_none()` - --> $DIR/redundant_pattern_matching.rs:94:19 + --> $DIR/redundant_pattern_matching.rs:97:19 | LL | } else if let None = gen_opt() { | -------^^^^------------ help: try this: `if gen_opt().is_none()` error: redundant pattern matching, consider using `is_ok()` - --> $DIR/redundant_pattern_matching.rs:96:19 + --> $DIR/redundant_pattern_matching.rs:99:19 | LL | } else if let Ok(_) = gen_res() { | -------^^^^^------------ help: try this: `if gen_res().is_ok()` error: redundant pattern matching, consider using `is_err()` - --> $DIR/redundant_pattern_matching.rs:98:19 + --> $DIR/redundant_pattern_matching.rs:101:19 | LL | } else if let Err(_) = gen_res() { | -------^^^^^^------------ help: try this: `if gen_res().is_err()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:131:19 + --> $DIR/redundant_pattern_matching.rs:134:19 | LL | while let Some(_) = r#try!(result_opt()) {} | ----------^^^^^^^----------------------- help: try this: `while r#try!(result_opt()).is_some()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:132:16 + --> $DIR/redundant_pattern_matching.rs:135:16 | LL | if let Some(_) = r#try!(result_opt()) {} | -------^^^^^^^----------------------- help: try this: `if r#try!(result_opt()).is_some()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:138:12 + --> $DIR/redundant_pattern_matching.rs:141:12 | LL | if let Some(_) = m!() {} | -------^^^^^^^------- help: try this: `if m!().is_some()` error: redundant pattern matching, consider using `is_some()` - --> $DIR/redundant_pattern_matching.rs:139:15 + --> $DIR/redundant_pattern_matching.rs:142:15 | LL | while let Some(_) = m!() {} | ----------^^^^^^^------- help: try this: `while m!().is_some()` diff --git a/tests/ui/redundant_pattern_matching_const_result.fixed b/tests/ui/redundant_pattern_matching_const_result.fixed new file mode 100644 index 00000000000..c8bc5458067 --- /dev/null +++ b/tests/ui/redundant_pattern_matching_const_result.fixed @@ -0,0 +1,46 @@ +// run-rustfix + +#![feature(const_if_match)] +#![feature(const_loop)] +#![feature(const_result)] +#![warn(clippy::redundant_pattern_matching)] +#![allow(unused)] + +// Test that results are linted with the feature enabled. + +const fn issue_5697() { + if Ok::(42).is_ok() {} + + if Err::(42).is_err() {} + + while Ok::(10).is_ok() {} + + while Ok::(10).is_err() {} + + Ok::(42).is_ok(); + + Err::(42).is_err(); + + // These should not be linted until `const_option` is implemented. + // See https://github.com/rust-lang/rust/issues/67441 + + if let Some(_) = Some(42) {} + + if let None = None::<()> {} + + while let Some(_) = Some(42) {} + + while let None = None::<()> {} + + match Some(42) { + Some(_) => true, + None => false, + }; + + match None::<()> { + Some(_) => false, + None => true, + }; +} + +fn main() {} diff --git a/tests/ui/redundant_pattern_matching_const_result.rs b/tests/ui/redundant_pattern_matching_const_result.rs new file mode 100644 index 00000000000..75f37ec15c6 --- /dev/null +++ b/tests/ui/redundant_pattern_matching_const_result.rs @@ -0,0 +1,52 @@ +// run-rustfix + +#![feature(const_if_match)] +#![feature(const_loop)] +#![feature(const_result)] +#![warn(clippy::redundant_pattern_matching)] +#![allow(unused)] + +// Test that results are linted with the feature enabled. + +const fn issue_5697() { + if let Ok(_) = Ok::(42) {} + + if let Err(_) = Err::(42) {} + + while let Ok(_) = Ok::(10) {} + + while let Err(_) = Ok::(10) {} + + match Ok::(42) { + Ok(_) => true, + Err(_) => false, + }; + + match Err::(42) { + Ok(_) => false, + Err(_) => true, + }; + + // These should not be linted until `const_option` is implemented. + // See https://github.com/rust-lang/rust/issues/67441 + + if let Some(_) = Some(42) {} + + if let None = None::<()> {} + + while let Some(_) = Some(42) {} + + while let None = None::<()> {} + + match Some(42) { + Some(_) => true, + None => false, + }; + + match None::<()> { + Some(_) => false, + None => true, + }; +} + +fn main() {} diff --git a/tests/ui/redundant_pattern_matching_const_result.stderr b/tests/ui/redundant_pattern_matching_const_result.stderr new file mode 100644 index 00000000000..c32292f0eee --- /dev/null +++ b/tests/ui/redundant_pattern_matching_const_result.stderr @@ -0,0 +1,46 @@ +error: redundant pattern matching, consider using `is_ok()` + --> $DIR/redundant_pattern_matching_const_result.rs:12:12 + | +LL | if let Ok(_) = Ok::(42) {} + | -------^^^^^--------------------- help: try this: `if Ok::(42).is_ok()` + | + = note: `-D clippy::redundant-pattern-matching` implied by `-D warnings` + +error: redundant pattern matching, consider using `is_err()` + --> $DIR/redundant_pattern_matching_const_result.rs:14:12 + | +LL | if let Err(_) = Err::(42) {} + | -------^^^^^^---------------------- help: try this: `if Err::(42).is_err()` + +error: redundant pattern matching, consider using `is_ok()` + --> $DIR/redundant_pattern_matching_const_result.rs:16:15 + | +LL | while let Ok(_) = Ok::(10) {} + | ----------^^^^^--------------------- help: try this: `while Ok::(10).is_ok()` + +error: redundant pattern matching, consider using `is_err()` + --> $DIR/redundant_pattern_matching_const_result.rs:18:15 + | +LL | while let Err(_) = Ok::(10) {} + | ----------^^^^^^--------------------- help: try this: `while Ok::(10).is_err()` + +error: redundant pattern matching, consider using `is_ok()` + --> $DIR/redundant_pattern_matching_const_result.rs:20:5 + | +LL | / match Ok::(42) { +LL | | Ok(_) => true, +LL | | Err(_) => false, +LL | | }; + | |_____^ help: try this: `Ok::(42).is_ok()` + +error: redundant pattern matching, consider using `is_err()` + --> $DIR/redundant_pattern_matching_const_result.rs:25:5 + | +LL | / match Err::(42) { +LL | | Ok(_) => false, +LL | | Err(_) => true, +LL | | }; + | |_____^ help: try this: `Err::(42).is_err()` + +error: aborting due to 6 previous errors +