diff options
| -rw-r--r-- | clippy_lints/src/question_mark.rs | 74 | ||||
| -rw-r--r-- | tests/ui/question_mark.fixed | 17 | ||||
| -rw-r--r-- | tests/ui/question_mark.rs | 19 | ||||
| -rw-r--r-- | tests/ui/question_mark.stderr | 16 |
4 files changed, 104 insertions, 22 deletions
diff --git a/clippy_lints/src/question_mark.rs b/clippy_lints/src/question_mark.rs index aa6d254e7a5..4d616e26bfc 100644 --- a/clippy_lints/src/question_mark.rs +++ b/clippy_lints/src/question_mark.rs @@ -4,10 +4,10 @@ use clippy_utils::is_lang_ctor; use clippy_utils::source::snippet_with_applicability; use clippy_utils::sugg::Sugg; use clippy_utils::ty::is_type_diagnostic_item; -use clippy_utils::{eq_expr_value, path_to_local_id}; +use clippy_utils::{eq_expr_value, path_to_local, path_to_local_id}; use if_chain::if_chain; use rustc_errors::Applicability; -use rustc_hir::LangItem::{OptionNone, OptionSome}; +use rustc_hir::LangItem::{OptionNone, OptionSome, ResultOk}; use rustc_hir::{BindingAnnotation, Block, Expr, ExprKind, PatKind, StmtKind}; use rustc_lint::{LateContext, LateLintPass}; use rustc_session::{declare_lint_pass, declare_tool_lint}; @@ -48,16 +48,20 @@ impl QuestionMark { /// } /// ``` /// + /// ```ignore + /// if result.is_err() { + /// return result; + /// } + /// ``` + /// /// If it matches, it will suggest to use the question mark operator instead - fn check_is_none_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) { + fn check_is_none_or_err_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>) { if_chain! { if let Some(higher::If { cond, then, r#else }) = higher::If::hir(expr); if let ExprKind::MethodCall(segment, _, args, _) = &cond.kind; - if segment.ident.name == sym!(is_none); - if Self::expression_returns_none(cx, then); if let Some(subject) = args.get(0); - if Self::is_option(cx, subject); - + if (Self::option_check_and_early_return(cx, subject, then) && segment.ident.name == sym!(is_none)) || + (Self::result_check_and_early_return(cx, subject, then) && segment.ident.name == sym!(is_err)); then { let mut applicability = Applicability::MachineApplicable; let receiver_str = &Sugg::hir_with_applicability(cx, subject, "..", &mut applicability); @@ -95,31 +99,24 @@ impl QuestionMark { } } - fn check_if_let_some_and_early_return_none(cx: &LateContext<'_>, expr: &Expr<'_>) { + fn check_if_let_some_or_err_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>) { if_chain! { if let Some(higher::IfLet { let_pat, let_expr, if_then, if_else: Some(if_else) }) = higher::IfLet::hir(cx, expr); - if Self::is_option(cx, let_expr); - if let PatKind::TupleStruct(ref path1, fields, None) = let_pat.kind; - if is_lang_ctor(cx, path1, OptionSome); + if (Self::option_check_and_early_return(cx, let_expr, if_else) && is_lang_ctor(cx, path1, OptionSome)) || + (Self::result_check_and_early_return(cx, let_expr, if_else) && is_lang_ctor(cx, path1, ResultOk)); + if let PatKind::Binding(annot, bind_id, _, _) = fields[0].kind; let by_ref = matches!(annot, BindingAnnotation::Ref | BindingAnnotation::RefMut); - if let ExprKind::Block(block, None) = if_then.kind; if block.stmts.is_empty(); if let Some(trailing_expr) = &block.expr; if path_to_local_id(trailing_expr, bind_id); - - if Self::expression_returns_none(cx, if_else); then { let mut applicability = Applicability::MachineApplicable; let receiver_str = snippet_with_applicability(cx, let_expr.span, "..", &mut applicability); - let replacement = format!( - "{}{}?", - receiver_str, - if by_ref { ".as_ref()" } else { "" }, - ); + let replacement = format!("{}{}?", receiver_str, if by_ref { ".as_ref()" } else { "" },); span_lint_and_sugg( cx, @@ -134,6 +131,14 @@ impl QuestionMark { } } + fn result_check_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>, nested_expr: &Expr<'_>) -> bool { + Self::is_result(cx, expr) && Self::expression_returns_unmodified_err(cx, nested_expr, expr) + } + + fn option_check_and_early_return(cx: &LateContext<'_>, expr: &Expr<'_>, nested_expr: &Expr<'_>) -> bool { + Self::is_option(cx, expr) && Self::expression_returns_none(cx, nested_expr) + } + fn moves_by_default(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool { let expr_ty = cx.typeck_results().expr_ty(expression); @@ -146,6 +151,12 @@ impl QuestionMark { is_type_diagnostic_item(cx, expr_ty, sym::Option) } + fn is_result(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool { + let expr_ty = cx.typeck_results().expr_ty(expression); + + is_type_diagnostic_item(cx, expr_ty, sym::Result) + } + fn expression_returns_none(cx: &LateContext<'_>, expression: &Expr<'_>) -> bool { match expression.kind { ExprKind::Block(block, _) => { @@ -161,6 +172,27 @@ impl QuestionMark { } } + fn expression_returns_unmodified_err( + cx: &LateContext<'_>, + expression: &Expr<'_>, + origin_hir_id: &Expr<'_>, + ) -> bool { + match expression.kind { + ExprKind::Block(block, _) => { + if let Some(return_expression) = Self::return_expression(block) { + return Self::expression_returns_unmodified_err(cx, return_expression, origin_hir_id); + } + + false + }, + ExprKind::Ret(Some(expr)) | ExprKind::Call(expr, _) => { + Self::expression_returns_unmodified_err(cx, expr, origin_hir_id) + }, + ExprKind::Path(_) => path_to_local(expression) == path_to_local(origin_hir_id), + _ => false, + } + } + fn return_expression<'tcx>(block: &Block<'tcx>) -> Option<&'tcx Expr<'tcx>> { // Check if last expression is a return statement. Then, return the expression if_chain! { @@ -189,7 +221,7 @@ impl QuestionMark { impl<'tcx> LateLintPass<'tcx> for QuestionMark { fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { - Self::check_is_none_and_early_return_none(cx, expr); - Self::check_if_let_some_and_early_return_none(cx, expr); + Self::check_is_none_or_err_and_early_return(cx, expr); + Self::check_if_let_some_or_err_and_early_return(cx, expr); } } diff --git a/tests/ui/question_mark.fixed b/tests/ui/question_mark.fixed index 0b5746cb522..ccb2e5a302e 100644 --- a/tests/ui/question_mark.fixed +++ b/tests/ui/question_mark.fixed @@ -104,6 +104,21 @@ fn func() -> Option<i32> { Some(0) } +fn result_func(x: Result<i32, &str>) -> Result<i32, &str> { + let _ = x?; + + x?; + + // No warning + let y = if let Ok(x) = x { + x + } else { + return Err("some error"); + }; + + Ok(y) +} + fn main() { some_func(Some(42)); some_func(None); @@ -123,4 +138,6 @@ fn main() { returns_something_similar_to_option(so); func(); + + let _ = result_func(Ok(42)); } diff --git a/tests/ui/question_mark.rs b/tests/ui/question_mark.rs index 0f0825c9334..ca3722371f5 100644 --- a/tests/ui/question_mark.rs +++ b/tests/ui/question_mark.rs @@ -134,6 +134,23 @@ fn func() -> Option<i32> { Some(0) } +fn result_func(x: Result<i32, &str>) -> Result<i32, &str> { + let _ = if let Ok(x) = x { x } else { return x }; + + if x.is_err() { + return x; + } + + // No warning + let y = if let Ok(x) = x { + x + } else { + return Err("some error"); + }; + + Ok(y) +} + fn main() { some_func(Some(42)); some_func(None); @@ -153,4 +170,6 @@ fn main() { returns_something_similar_to_option(so); func(); + + let _ = result_func(Ok(42)); } diff --git a/tests/ui/question_mark.stderr b/tests/ui/question_mark.stderr index 6f330cfa385..161588cb73c 100644 --- a/tests/ui/question_mark.stderr +++ b/tests/ui/question_mark.stderr @@ -100,5 +100,19 @@ LL | | return None; LL | | } | |_____^ help: replace it with: `f()?;` -error: aborting due to 11 previous errors +error: this if-let-else may be rewritten with the `?` operator + --> $DIR/question_mark.rs:138:13 + | +LL | let _ = if let Ok(x) = x { x } else { return x }; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: replace it with: `x?` + +error: this block may be rewritten with the `?` operator + --> $DIR/question_mark.rs:140:5 + | +LL | / if x.is_err() { +LL | | return x; +LL | | } + | |_____^ help: replace it with: `x?;` + +error: aborting due to 13 previous errors |