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Auto merge of #7806 - Serial-ATA:lint-match-case-mismatch, r=llogiq
Add match_str_case_mismatch lint changelog: Added a new lint [`match_str_case_mismatch`] Fixes #7440
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,171 @@ | ||
| use clippy_utils::diagnostics::span_lint_and_sugg; | ||
| use clippy_utils::ty::is_type_diagnostic_item; | ||
| use rustc_ast::ast::LitKind; | ||
| use rustc_errors::Applicability; | ||
| use rustc_hir::intravisit::{walk_expr, NestedVisitorMap, Visitor}; | ||
| use rustc_hir::{Arm, Expr, ExprKind, MatchSource, PatKind}; | ||
| use rustc_lint::{LateContext, LateLintPass}; | ||
| use rustc_middle::hir::map::Map; | ||
| use rustc_middle::lint::in_external_macro; | ||
| use rustc_middle::ty; | ||
| use rustc_session::{declare_lint_pass, declare_tool_lint}; | ||
| use rustc_span::symbol::SymbolStr; | ||
| use rustc_span::{sym, Span}; | ||
|
|
||
| declare_clippy_lint! { | ||
| /// ### What it does | ||
| /// Checks for `match` expressions modifying the case of a string with non-compliant arms | ||
| /// | ||
| /// ### Why is this bad? | ||
| /// The arm is unreachable, which is likely a mistake | ||
| /// | ||
| /// ### Example | ||
| /// ```rust | ||
| /// # let text = "Foo"; | ||
| /// | ||
| /// match &*text.to_ascii_lowercase() { | ||
| /// "foo" => {}, | ||
| /// "Bar" => {}, | ||
| /// _ => {}, | ||
| /// } | ||
| /// ``` | ||
| /// Use instead: | ||
| /// ```rust | ||
| /// # let text = "Foo"; | ||
| /// | ||
| /// match &*text.to_ascii_lowercase() { | ||
| /// "foo" => {}, | ||
| /// "bar" => {}, | ||
| /// _ => {}, | ||
| /// } | ||
| /// ``` | ||
| pub MATCH_STR_CASE_MISMATCH, | ||
| correctness, | ||
| "creation of a case altering match expression with non-compliant arms" | ||
| } | ||
|
|
||
| declare_lint_pass!(MatchStrCaseMismatch => [MATCH_STR_CASE_MISMATCH]); | ||
|
|
||
| #[derive(Debug)] | ||
| enum CaseMethod { | ||
| LowerCase, | ||
| AsciiLowerCase, | ||
| UpperCase, | ||
| AsciiUppercase, | ||
| } | ||
|
|
||
| impl LateLintPass<'_> for MatchStrCaseMismatch { | ||
| fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { | ||
| if_chain! { | ||
| if !in_external_macro(cx.tcx.sess, expr.span); | ||
| if let ExprKind::Match(match_expr, arms, MatchSource::Normal) = expr.kind; | ||
| if let ty::Ref(_, ty, _) = cx.typeck_results().expr_ty(match_expr).kind(); | ||
| if let ty::Str = ty.kind(); | ||
| then { | ||
| let mut visitor = MatchExprVisitor { | ||
| cx, | ||
| case_method: None, | ||
| }; | ||
|
|
||
| visitor.visit_expr(match_expr); | ||
|
|
||
| if let Some(case_method) = visitor.case_method { | ||
| if let Some((bad_case_span, bad_case_str)) = verify_case(&case_method, arms) { | ||
| lint(cx, &case_method, bad_case_span, &bad_case_str); | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| struct MatchExprVisitor<'a, 'tcx> { | ||
| cx: &'a LateContext<'tcx>, | ||
| case_method: Option<CaseMethod>, | ||
| } | ||
|
|
||
| impl<'a, 'tcx> Visitor<'tcx> for MatchExprVisitor<'a, 'tcx> { | ||
| type Map = Map<'tcx>; | ||
|
|
||
| fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> { | ||
| NestedVisitorMap::None | ||
| } | ||
|
|
||
| fn visit_expr(&mut self, ex: &'tcx Expr<'_>) { | ||
| match ex.kind { | ||
| ExprKind::MethodCall(segment, _, [receiver], _) | ||
| if self.case_altered(&*segment.ident.as_str(), receiver) => {}, | ||
| _ => walk_expr(self, ex), | ||
| } | ||
| } | ||
| } | ||
|
|
||
| impl<'a, 'tcx> MatchExprVisitor<'a, 'tcx> { | ||
| fn case_altered(&mut self, segment_ident: &str, receiver: &Expr<'_>) -> bool { | ||
| if let Some(case_method) = get_case_method(segment_ident) { | ||
| let ty = self.cx.typeck_results().expr_ty(receiver).peel_refs(); | ||
|
|
||
| if is_type_diagnostic_item(self.cx, ty, sym::String) || ty.kind() == &ty::Str { | ||
| self.case_method = Some(case_method); | ||
| return true; | ||
| } | ||
| } | ||
|
|
||
| false | ||
| } | ||
| } | ||
|
|
||
| fn get_case_method(segment_ident_str: &str) -> Option<CaseMethod> { | ||
| match segment_ident_str { | ||
| "to_lowercase" => Some(CaseMethod::LowerCase), | ||
| "to_ascii_lowercase" => Some(CaseMethod::AsciiLowerCase), | ||
| "to_uppercase" => Some(CaseMethod::UpperCase), | ||
| "to_ascii_uppercase" => Some(CaseMethod::AsciiUppercase), | ||
| _ => None, | ||
| } | ||
| } | ||
|
|
||
| fn verify_case<'a>(case_method: &'a CaseMethod, arms: &'a [Arm<'_>]) -> Option<(Span, SymbolStr)> { | ||
| let case_check = match case_method { | ||
| CaseMethod::LowerCase => |input: &str| -> bool { input.chars().all(char::is_lowercase) }, | ||
| CaseMethod::AsciiLowerCase => |input: &str| -> bool { input.chars().all(|c| matches!(c, 'a'..='z')) }, | ||
| CaseMethod::UpperCase => |input: &str| -> bool { input.chars().all(char::is_uppercase) }, | ||
| CaseMethod::AsciiUppercase => |input: &str| -> bool { input.chars().all(|c| matches!(c, 'A'..='Z')) }, | ||
| }; | ||
|
|
||
| for arm in arms { | ||
| if_chain! { | ||
| if let PatKind::Lit(Expr { | ||
| kind: ExprKind::Lit(lit), | ||
| .. | ||
| }) = arm.pat.kind; | ||
| if let LitKind::Str(symbol, _) = lit.node; | ||
| let input = symbol.as_str(); | ||
| if !case_check(&input); | ||
| then { | ||
| return Some((lit.span, input)); | ||
| } | ||
| } | ||
| } | ||
|
|
||
| None | ||
| } | ||
|
|
||
| fn lint(cx: &LateContext<'_>, case_method: &CaseMethod, bad_case_span: Span, bad_case_str: &str) { | ||
| let (method_str, suggestion) = match case_method { | ||
| CaseMethod::LowerCase => ("to_lower_case", bad_case_str.to_lowercase()), | ||
| CaseMethod::AsciiLowerCase => ("to_ascii_lowercase", bad_case_str.to_ascii_lowercase()), | ||
| CaseMethod::UpperCase => ("to_uppercase", bad_case_str.to_uppercase()), | ||
| CaseMethod::AsciiUppercase => ("to_ascii_uppercase", bad_case_str.to_ascii_uppercase()), | ||
| }; | ||
|
|
||
| span_lint_and_sugg( | ||
| cx, | ||
| MATCH_STR_CASE_MISMATCH, | ||
| bad_case_span, | ||
| "this `match` arm has a differing case than its expression", | ||
| &*format!("consider changing the case of this arm to respect `{}`", method_str), | ||
| format!("\"{}\"", suggestion), | ||
| Applicability::MachineApplicable, | ||
| ); | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,98 @@ | ||
| #![warn(clippy::match_str_case_mismatch)] | ||
|
|
||
| // Valid | ||
|
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||
| fn as_str_match() { | ||
| let var = "BAR"; | ||
|
|
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| match var.to_ascii_lowercase().as_str() { | ||
| "foo" => {}, | ||
| "bar" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| fn addrof_unary_match() { | ||
| let var = "BAR"; | ||
|
|
||
| match &*var.to_ascii_lowercase() { | ||
| "foo" => {}, | ||
| "bar" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| fn alternating_chain() { | ||
| let var = "BAR"; | ||
|
|
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| match &*var | ||
| .to_ascii_lowercase() | ||
| .to_uppercase() | ||
| .to_lowercase() | ||
| .to_ascii_uppercase() | ||
| { | ||
| "FOO" => {}, | ||
| "BAR" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| fn unrelated_method() { | ||
| struct Item { | ||
| a: String, | ||
| } | ||
|
|
||
| impl Item { | ||
| #[allow(clippy::wrong_self_convention)] | ||
| fn to_lowercase(self) -> String { | ||
| self.a | ||
| } | ||
| } | ||
|
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| let item = Item { a: String::from("BAR") }; | ||
|
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| match &*item.to_lowercase() { | ||
| "FOO" => {}, | ||
| "BAR" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| // Invalid | ||
|
|
||
| fn as_str_match_mismatch() { | ||
| let var = "BAR"; | ||
|
|
||
| match var.to_ascii_lowercase().as_str() { | ||
| "foo" => {}, | ||
| "Bar" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| fn addrof_unary_match_mismatch() { | ||
| let var = "BAR"; | ||
|
|
||
| match &*var.to_ascii_lowercase() { | ||
| "foo" => {}, | ||
| "Bar" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| fn alternating_chain_mismatch() { | ||
| let var = "BAR"; | ||
|
|
||
| match &*var | ||
| .to_ascii_lowercase() | ||
| .to_uppercase() | ||
| .to_lowercase() | ||
| .to_ascii_uppercase() | ||
| { | ||
| "FOO" => {}, | ||
| "bAR" => {}, | ||
| _ => {}, | ||
| } | ||
| } | ||
|
|
||
| fn main() {} |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,36 @@ | ||
| error: this `match` arm has a differing case than its expression | ||
| --> $DIR/match_str_case_mismatch.rs:68:9 | ||
| | | ||
| LL | "Bar" => {}, | ||
| | ^^^^^ | ||
| | | ||
| = note: `-D clippy::match-str-case-mismatch` implied by `-D warnings` | ||
| help: consider changing the case of this arm to respect `to_ascii_lowercase` | ||
| | | ||
| LL | "bar" => {}, | ||
| | ~~~~~ | ||
|
|
||
| error: this `match` arm has a differing case than its expression | ||
| --> $DIR/match_str_case_mismatch.rs:78:9 | ||
| | | ||
| LL | "Bar" => {}, | ||
| | ^^^^^ | ||
| | | ||
| help: consider changing the case of this arm to respect `to_ascii_lowercase` | ||
| | | ||
| LL | "bar" => {}, | ||
| | ~~~~~ | ||
|
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||
| error: this `match` arm has a differing case than its expression | ||
| --> $DIR/match_str_case_mismatch.rs:93:9 | ||
| | | ||
| LL | "bAR" => {}, | ||
| | ^^^^^ | ||
| | | ||
| help: consider changing the case of this arm to respect `to_ascii_uppercase` | ||
| | | ||
| LL | "BAR" => {}, | ||
| | ~~~~~ | ||
|
|
||
| error: aborting due to 3 previous errors | ||
|
|