and check for Result

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J-ZhengLi 2022-04-16 17:40:28 +08:00 committed by Philipp Krones
parent 5d403c0b85
commit ffe7125163
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GPG Key ID: 1CA0DF2AF59D68A5
3 changed files with 39 additions and 29 deletions

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@ -1,19 +1,17 @@
use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::diagnostics::span_lint_and_sugg;
use clippy_utils::sugg::Sugg; use clippy_utils::sugg::Sugg;
use clippy_utils::ty::is_type_diagnostic_item;
use clippy_utils::{ use clippy_utils::{
can_move_expr_to_closure, eager_or_lazy, higher, in_constant, is_else_clause, is_lang_ctor, peel_blocks, can_move_expr_to_closure, eager_or_lazy, higher, in_constant, is_else_clause, is_lang_ctor, peel_blocks,
peel_hir_expr_while, CaptureKind, peel_hir_expr_while, CaptureKind,
}; };
use if_chain::if_chain; use if_chain::if_chain;
use rustc_errors::Applicability; use rustc_errors::Applicability;
use rustc_hir::LangItem::{OptionNone, OptionSome}; use rustc_hir::LangItem::{OptionNone, OptionSome, ResultErr, ResultOk};
use rustc_hir::{ use rustc_hir::{
def::Res, Arm, BindingAnnotation, Expr, ExprKind, MatchSource, Mutability, Pat, PatKind, Path, QPath, UnOp, def::Res, Arm, BindingAnnotation, Expr, ExprKind, MatchSource, Mutability, Pat, PatKind, Path, QPath, UnOp,
}; };
use rustc_lint::{LateContext, LateLintPass}; use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint}; use rustc_session::{declare_lint_pass, declare_tool_lint};
use rustc_span::sym;
declare_clippy_lint! { declare_clippy_lint! {
/// ### What it does /// ### What it does
@ -74,16 +72,6 @@ declare_clippy_lint! {
declare_lint_pass!(OptionIfLetElse => [OPTION_IF_LET_ELSE]); declare_lint_pass!(OptionIfLetElse => [OPTION_IF_LET_ELSE]);
/// Returns true iff the given expression is the result of calling `Result::ok`
fn is_result_ok(cx: &LateContext<'_>, expr: &'_ Expr<'_>) -> bool {
if let ExprKind::MethodCall(path, &[ref receiver], _) = &expr.kind {
path.ident.name.as_str() == "ok"
&& is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(receiver), sym::Result)
} else {
false
}
}
/// A struct containing information about occurrences of construct that this lint detects /// A struct containing information about occurrences of construct that this lint detects
/// ///
/// Such as: /// Such as:
@ -130,9 +118,8 @@ fn try_get_option_occurence<'tcx>(
ExprKind::Unary(UnOp::Deref, inner_expr) | ExprKind::AddrOf(_, _, inner_expr) => inner_expr, ExprKind::Unary(UnOp::Deref, inner_expr) | ExprKind::AddrOf(_, _, inner_expr) => inner_expr,
_ => expr, _ => expr,
}; };
let inner_pat = try_get_inner_pat(cx, pat)?;
if_chain! { if_chain! {
if !is_result_ok(cx, cond_expr); // Don't lint on Result::ok because a different lint does it already
let inner_pat = try_get_inner_pat(cx, pat)?;
if let PatKind::Binding(bind_annotation, _, id, None) = inner_pat.kind; if let PatKind::Binding(bind_annotation, _, id, None) = inner_pat.kind;
if let Some(some_captures) = can_move_expr_to_closure(cx, if_then); if let Some(some_captures) = can_move_expr_to_closure(cx, if_then);
if let Some(none_captures) = can_move_expr_to_closure(cx, if_else); if let Some(none_captures) = can_move_expr_to_closure(cx, if_else);
@ -185,7 +172,7 @@ fn try_get_option_occurence<'tcx>(
fn try_get_inner_pat<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'tcx>) -> Option<&'tcx Pat<'tcx>> { fn try_get_inner_pat<'tcx>(cx: &LateContext<'tcx>, pat: &Pat<'tcx>) -> Option<&'tcx Pat<'tcx>> {
if let PatKind::TupleStruct(ref qpath, [inner_pat], ..) = pat.kind { if let PatKind::TupleStruct(ref qpath, [inner_pat], ..) = pat.kind {
if is_lang_ctor(cx, qpath, OptionSome) { if is_lang_ctor(cx, qpath, OptionSome) || is_lang_ctor(cx, qpath, ResultOk) {
return Some(inner_pat); return Some(inner_pat);
} }
} }
@ -224,9 +211,9 @@ fn try_convert_match<'tcx>(
arms: &[Arm<'tcx>], arms: &[Arm<'tcx>],
) -> Option<(&'tcx Pat<'tcx>, &'tcx Expr<'tcx>, &'tcx Expr<'tcx>)> { ) -> Option<(&'tcx Pat<'tcx>, &'tcx Expr<'tcx>, &'tcx Expr<'tcx>)> {
if arms.len() == 2 { if arms.len() == 2 {
return if is_none_arm(cx, &arms[1]) { return if is_none_or_err_arm(cx, &arms[1]) {
Some((arms[0].pat, arms[0].body, arms[1].body)) Some((arms[0].pat, arms[0].body, arms[1].body))
} else if is_none_arm(cx, &arms[0]) { } else if is_none_or_err_arm(cx, &arms[0]) {
Some((arms[1].pat, arms[1].body, arms[0].body)) Some((arms[1].pat, arms[1].body, arms[0].body))
} else { } else {
None None
@ -235,9 +222,12 @@ fn try_convert_match<'tcx>(
None None
} }
fn is_none_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool { fn is_none_or_err_arm(cx: &LateContext<'_>, arm: &Arm<'_>) -> bool {
match arm.pat.kind { match arm.pat.kind {
PatKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone), PatKind::Path(ref qpath) => is_lang_ctor(cx, qpath, OptionNone),
PatKind::TupleStruct(ref qpath, [first_pat], _) => {
is_lang_ctor(cx, qpath, ResultErr) && matches!(first_pat.kind, PatKind::Wild)
},
PatKind::Wild => true, PatKind::Wild => true,
_ => false, _ => false,
} }

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@ -185,13 +185,7 @@ fn main() {
let _ = Some(10).map_or(5, |a| a + 1); let _ = Some(10).map_or(5, |a| a + 1);
let res: Result<i32, i32> = Ok(5); let res: Result<i32, i32> = Ok(5);
let _ = match res { let _ = res.map_or(1, |a| a + 1);
Ok(a) => a + 1, let _ = res.map_or(1, |a| a + 1);
_ => 1, let _ = res.map_or(5, |a| a + 1);
};
let _ = match res {
Err(_) => 1,
Ok(a) => a + 1,
};
let _ = if let Ok(a) = res { a + 1 } else { 5 };
} }

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@ -226,5 +226,31 @@ LL | | None => 5,
LL | | }; LL | | };
| |_____^ help: try: `Some(10).map_or(5, |a| a + 1)` | |_____^ help: try: `Some(10).map_or(5, |a| a + 1)`
error: aborting due to 17 previous errors error: use Option::map_or instead of an if let/else
--> $DIR/option_if_let_else.rs:222:13
|
LL | let _ = match res {
| _____________^
LL | | Ok(a) => a + 1,
LL | | _ => 1,
LL | | };
| |_____^ help: try: `res.map_or(1, |a| a + 1)`
error: use Option::map_or instead of an if let/else
--> $DIR/option_if_let_else.rs:226:13
|
LL | let _ = match res {
| _____________^
LL | | Err(_) => 1,
LL | | Ok(a) => a + 1,
LL | | };
| |_____^ help: try: `res.map_or(1, |a| a + 1)`
error: use Option::map_or instead of an if let/else
--> $DIR/option_if_let_else.rs:230:13
|
LL | let _ = if let Ok(a) = res { a + 1 } else { 5 };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `res.map_or(5, |a| a + 1)`
error: aborting due to 20 previous errors