diff options
| -rw-r--r-- | clippy_lints/src/matches/redundant_guards.rs | 53 |
1 files changed, 40 insertions, 13 deletions
diff --git a/clippy_lints/src/matches/redundant_guards.rs b/clippy_lints/src/matches/redundant_guards.rs index 4a44d596a46..9cc546de22e 100644 --- a/clippy_lints/src/matches/redundant_guards.rs +++ b/clippy_lints/src/matches/redundant_guards.rs @@ -1,6 +1,6 @@ use clippy_utils::diagnostics::span_lint_and_then; use clippy_utils::path_to_local; -use clippy_utils::source::snippet_with_applicability; +use clippy_utils::source::snippet; use clippy_utils::visitors::{for_each_expr, is_local_used}; use rustc_ast::{BorrowKind, LitKind}; use rustc_errors::Applicability; @@ -9,6 +9,7 @@ use rustc_hir::{Arm, BinOpKind, Expr, ExprKind, Guard, MatchSource, Node, Pat, P use rustc_lint::LateContext; use rustc_span::symbol::Ident; use rustc_span::Span; +use std::borrow::Cow; use std::ops::ControlFlow; use super::REDUNDANT_GUARDS; @@ -41,7 +42,14 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'tcx>]) { (PatKind::Ref(..), None) | (_, Some(_)) => continue, _ => arm.pat.span, }; - emit_redundant_guards(cx, outer_arm, if_expr.span, pat_span, &binding, arm.guard); + emit_redundant_guards( + cx, + outer_arm, + if_expr.span, + snippet(cx, pat_span, "<binding>"), + &binding, + arm.guard, + ); } // `Some(x) if let Some(2) = x` else if let Guard::IfLet(let_expr) = guard @@ -52,7 +60,14 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'tcx>]) { (PatKind::Ref(..), None) | (_, Some(_)) => continue, _ => let_expr.pat.span, }; - emit_redundant_guards(cx, outer_arm, let_expr.span, pat_span, &binding, None); + emit_redundant_guards( + cx, + outer_arm, + let_expr.span, + snippet(cx, pat_span, "<binding>"), + &binding, + None, + ); } // `Some(x) if x == Some(2)` // `Some(x) if Some(2) == x` @@ -78,7 +93,25 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, arms: &'tcx [Arm<'tcx>]) { (ExprKind::AddrOf(..), None) | (_, Some(_)) => continue, _ => pat.span, }; - emit_redundant_guards(cx, outer_arm, if_expr.span, pat_span, &binding, None); + emit_redundant_guards( + cx, + outer_arm, + if_expr.span, + snippet(cx, pat_span, "<binding>"), + &binding, + None, + ); + } else if let Guard::If(if_expr) = guard + && let ExprKind::MethodCall(path, recv, ..) = if_expr.kind + && let Some(binding) = get_pat_binding(cx, recv, outer_arm) + { + let ty = cx.typeck_results().expr_ty(recv).peel_refs(); + + if path.ident.name == sym!(is_empty) && ty.is_str() { + // `s if s.is_empty()` becomes "" + + emit_redundant_guards(cx, outer_arm, if_expr.span, r#""""#.into(), &binding, None) + } } } } @@ -134,19 +167,16 @@ fn emit_redundant_guards<'tcx>( cx: &LateContext<'tcx>, outer_arm: &Arm<'tcx>, guard_span: Span, - pat_span: Span, + binding_replacement: Cow<'static, str>, pat_binding: &PatBindingInfo, inner_guard: Option<Guard<'_>>, ) { - let mut app = Applicability::MaybeIncorrect; - span_lint_and_then( cx, REDUNDANT_GUARDS, guard_span.source_callsite(), "redundant guard", |diag| { - let binding_replacement = snippet_with_applicability(cx, pat_span, "<binding_repl>", &mut app); let suggestion_span = match *pat_binding { PatBindingInfo { span, @@ -170,14 +200,11 @@ fn emit_redundant_guards<'tcx>( Guard::IfLet(l) => ("if let", l.span), }; - format!( - " {prefix} {}", - snippet_with_applicability(cx, span, "<guard>", &mut app), - ) + format!(" {prefix} {}", snippet(cx, span, "<guard>")) }), ), ], - app, + Applicability::MaybeIncorrect, ); }, ); |